diff --git a/build.gradle.kts b/build.gradle.kts
index fb67a8f..ed34796 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -51,12 +51,6 @@ subprojects {
         testAnnotationProcessor("org.projectlombok:lombok:$lombokVersion")
     }
 
-    repositories {
-        mavenLocal()
-        maven(url = "https://maven.proxy.ustclug.org/maven2/")
-        mavenCentral()
-    }
-
     tasks.withType<JavaCompile> {
         options.encoding = "UTF-8"
     }
diff --git a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/AesUtil.java b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/AesUtil.java
index bc9ec22..14baad1 100644
--- a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/AesUtil.java
+++ b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/AesUtil.java
@@ -34,8 +34,7 @@
 import java.util.UUID;
 
 /**
- * {@link AesUtil} can help you encrypt and decrypt data with specified secret
- * by AES algorithm.
+ * {@link AesUtil} can help you encrypt and decrypt data with specified secret by AES algorithm.
  *
  * @author hubin@baomidou
  * @version 1.1.0
@@ -81,8 +80,9 @@ public static byte[] decrypt(byte[] data, byte[] secret) {
             var cipher = Cipher.getInstance(AES_CBC_CIPHER);
             cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, new IvParameterSpec(secret));
             return cipher.doFinal(data);
-        } catch (NoSuchAlgorithmException | NoSuchPaddingException | UnsupportedOperationException |
-                 InvalidKeyException | InvalidAlgorithmParameterException | IllegalBlockSizeException |
+        } catch (NoSuchAlgorithmException | NoSuchPaddingException |
+                 UnsupportedOperationException | InvalidKeyException |
+                 InvalidAlgorithmParameterException | IllegalBlockSizeException |
                  BadPaddingException exception) {
             log.error(exception.getMessage());
             for (var stackTraceElement : exception.getStackTrace()) {
@@ -100,7 +100,8 @@ public static byte[] decrypt(byte[] data, byte[] secret) {
      * @return the encryption result or {@code null} if encryption failed
      */
     public static String encrypt(String data, String secret) {
-        return Base64.getEncoder().encodeToString(encrypt(data.getBytes(StandardCharsets.UTF_8), secret.getBytes(StandardCharsets.UTF_8)));
+        return Base64.getEncoder().encodeToString(encrypt(data.getBytes(StandardCharsets.UTF_8),
+                secret.getBytes(StandardCharsets.UTF_8)));
     }
 
     /**
diff --git a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/Base64Util.java b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/Base64Util.java
index 41a0cc3..18802bf 100644
--- a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/Base64Util.java
+++ b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/Base64Util.java
@@ -49,7 +49,7 @@
  * provided. It is recommended to specify the charset explicitly to ensure consistent
  * encoding and decoding.
  *
- * @author Zihlu Wang
+ * @author zihluwang
  * @version 1.1.0
  * @since 1.0.0
  */
diff --git a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/ChainedCalcUtil.java b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/ChainedCalcUtil.java
index a8f395e..2ee3092 100644
--- a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/ChainedCalcUtil.java
+++ b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/ChainedCalcUtil.java
@@ -293,7 +293,9 @@ private ChainedCalcUtil operator(BiFunction<BigDecimal, BigDecimal, BigDecimal>
      *                           or null if not applicable
      * @return a ChainedCalcUtil instance with the updated value
      */
-    private ChainedCalcUtil operator(BiFunction<BigDecimal, BigDecimal, BigDecimal> operator, Object other, Integer beforeOperateScale) {
+    private ChainedCalcUtil operator(BiFunction<BigDecimal, BigDecimal, BigDecimal> operator,
+                                     Object other,
+                                     Integer beforeOperateScale) {
         return baseOperator((otherValue) ->
                 operator.apply(this.value, otherValue),
                 other,
@@ -311,7 +313,8 @@ private ChainedCalcUtil operator(BiFunction<BigDecimal, BigDecimal, BigDecimal>
      * @return a ChainedCalcUtil instance with the updated value
      */
     private synchronized ChainedCalcUtil baseOperator(Function<BigDecimal, BigDecimal> operatorFunction,
-                                                      Object anotherValue, Integer beforeOperateScale) {
+                                                      Object anotherValue,
+                                                      Integer beforeOperateScale) {
         if (Objects.isNull(anotherValue)) {
             return this;
         }
diff --git a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/HashUtil.java b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/HashUtil.java
index f0e4c59..2c24283 100644
--- a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/HashUtil.java
+++ b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/HashUtil.java
@@ -61,7 +61,7 @@
  * for data integrity checks and password storage, but they should not be used for
  * encryption purposes.
  *
- * @author Zihlu Wang
+ * @author zihluwang
  * @version 1.1.0
  * @see java.security.MessageDigest
  * @since 1.0.0
diff --git a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/MapUtil.java b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/MapUtil.java
index aa23699..195020c 100644
--- a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/MapUtil.java
+++ b/devkit-utils/src/main/java/com/onixbyte/devkit/utils/MapUtil.java
@@ -30,9 +30,8 @@
  * Note: Since version 1.4.2, this util class removed reflection API and transferred to a safer API.
  * Please see documentation for more information.
  *
- * @author Zihlu Wang
+ * @author zihluwang
  * @version 1.4.2
- * @see com.onixbyte.devkit.utils.unsafe.ReflectMapUtil
  * @since 1.0.0
  */
 @Slf4j
diff --git a/gradle.properties b/gradle.properties
index 7812492..c4abfd9 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -15,9 +15,9 @@
 # limitations under the License.
 #
 
-jacksonVersion=2.17.0
+jacksonVersion=2.17.2
 javaJwtVersion=4.4.0
-jjwtVersion=0.12.5
+jjwtVersion=0.12.6
 junitVersion=5.10.2
 logbackVersion=1.5.4
 lombokVersion=1.18.30
@@ -26,7 +26,7 @@ springVersion=6.1.3
 springBootVersion=3.2.3
 
 buildGroupId=com.onixbyte
-buildVersion=1.5.0
+buildVersion=1.6.0
 projectUrl=https://onixbyte.com/JDevKit
 projectGithubUrl=https://github.com/OnixByte/JDevKit
 licenseName=The Apache License, Version 2.0
diff --git a/simple-jwt-jjwt/build.gradle.kts b/key-pair-loader/build.gradle.kts
similarity index 76%
rename from simple-jwt-jjwt/build.gradle.kts
rename to key-pair-loader/build.gradle.kts
index 30d6484..17c4fd3 100644
--- a/simple-jwt-jjwt/build.gradle.kts
+++ b/key-pair-loader/build.gradle.kts
@@ -24,20 +24,11 @@ val projectGithubUrl: String by project
 val licenseName: String by project
 val licenseUrl: String by project
 
-val jacksonVersion: String by project
-val jjwtVersion: String by project
-
 group = buildGroupId
 version = buildVersion
 
 dependencies {
-    implementation(project(":devkit-utils"))
-    implementation(project(":guid"))
-    implementation("com.fasterxml.jackson.core:jackson-databind:$jacksonVersion")
-    implementation("io.jsonwebtoken:jjwt-api:$jjwtVersion")
-    implementation("io.jsonwebtoken:jjwt-impl:$jjwtVersion")
-    implementation("io.jsonwebtoken:jjwt-jackson:$jjwtVersion")
-    implementation(project(":simple-jwt-facade"))
+    implementation(project(":devkit-core"))
 }
 
 java {
@@ -53,14 +44,15 @@ tasks.test {
 
 publishing {
     publications {
-        create<MavenPublication>("simpleJwtJjwt") {
+        create<MavenPublication>("keyPairLoader") {
             groupId = buildGroupId
-            artifactId = "simple-jwt-jjwt"
+            artifactId = "key-pair-loader"
             version = buildVersion
 
             pom {
-                name = "Simple JWT :: JJWT"
-                description = "SSimple JWT implemented with io.jsonwebtoken:jjwt."
+                name = "Key Pair Loader"
+                description =
+                    "This module can easily load key pairs from a PEM content."
                 url = projectUrl
 
                 licenses {
@@ -89,7 +81,7 @@ publishing {
             from(components["java"])
 
             signing {
-                sign(publishing.publications["simpleJwtJjwt"])
+                sign(publishing.publications["keyPairLoader"])
             }
         }
 
diff --git a/key-pair-loader/src/main/java/com/onixbyte/security/KeyLoader.java b/key-pair-loader/src/main/java/com/onixbyte/security/KeyLoader.java
new file mode 100644
index 0000000..4a4b3e1
--- /dev/null
+++ b/key-pair-loader/src/main/java/com/onixbyte/security/KeyLoader.java
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.security;
+
+import com.onixbyte.security.exception.KeyLoadingException;
+import lombok.extern.slf4j.Slf4j;
+
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.interfaces.ECPrivateKey;
+import java.security.interfaces.ECPublicKey;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.PKCS8EncodedKeySpec;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.Base64;
+
+/**
+ * KeyLoader can load key pairs from PEM formated content.
+ *
+ * @author zihluwang
+ * @version 1.6.0
+ * @since 1.6.0
+ */
+@Slf4j
+public class KeyLoader {
+
+    /**
+     * Private constructor prevents from being initialised.
+     */
+    private KeyLoader() {
+    }
+
+    /**
+     * Load ECDSA private key from pem-formatted key text.
+     *
+     * @param pemKeyText pem-formatted key text
+     * @return loaded private key
+     * @throws KeyLoadingException if the generated key is not a {@link ECPrivateKey} instance,
+     *                             or EC Key Factory is not loaded, or key spec is invalid
+     */
+    public static ECPrivateKey loadEcdsaPrivateKey(String pemKeyText) {
+        try {
+            var decodedKeyString = Base64.getDecoder().decode(pemKeyText);
+            var keySpec = new PKCS8EncodedKeySpec(decodedKeyString);
+            var keyFactory = KeyFactory.getInstance("EC");
+            var _key = keyFactory.generatePrivate(keySpec);
+            if (_key instanceof ECPrivateKey privateKey) {
+                return privateKey;
+            } else {
+                throw new KeyLoadingException("Unable to load private key from pem-formatted key text.");
+            }
+        } catch (NoSuchAlgorithmException e) {
+            throw new KeyLoadingException("Cannot get EC Key Factory.", e);
+        } catch (InvalidKeySpecException e) {
+            throw new KeyLoadingException("Key spec is invalid.", e);
+        }
+    }
+
+    /**
+     * Load ECDSA public key from pem-formatted key text.
+     *
+     * @param pemKeyText pem-formatted key text
+     * @return loaded private key
+     * @throws KeyLoadingException if the generated key is not a {@link ECPrivateKey} instance,
+     *                             or EC Key Factory is not loaded, or key spec is invalid
+     */
+    public static ECPublicKey loadEcdsaPublicKey(String pemKeyText) {
+        try {
+            var keyBytes = Base64.getDecoder().decode(pemKeyText);
+            var spec = new X509EncodedKeySpec(keyBytes);
+            var keyFactory = KeyFactory.getInstance("EC");
+            var key = keyFactory.generatePublic(spec);
+            if (key instanceof ECPublicKey publicKey) {
+                return publicKey;
+            } else {
+                throw new KeyLoadingException("Unable to load private key from pem-formatted key text.");
+            }
+        } catch (NoSuchAlgorithmException e) {
+            throw new KeyLoadingException("Cannot get EC Key Factory.", e);
+        } catch (InvalidKeySpecException e) {
+            throw new KeyLoadingException("Key spec is invalid.", e);
+        }
+    }
+
+}
diff --git a/key-pair-loader/src/main/java/com/onixbyte/security/exception/KeyLoadingException.java b/key-pair-loader/src/main/java/com/onixbyte/security/exception/KeyLoadingException.java
new file mode 100644
index 0000000..2c36b10
--- /dev/null
+++ b/key-pair-loader/src/main/java/com/onixbyte/security/exception/KeyLoadingException.java
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.security.exception;
+
+/**
+ * {@code KeyLoadingException} is an exception indicating an error occurred while loading a key.
+ *
+ * @author zihluwang
+ * @version 1.6.0
+ * @since 1.6.0
+ */
+public class KeyLoadingException extends RuntimeException {
+
+    /**
+     * Creates a new instance of {@code KeyLoadingException} without a specific message or cause.
+     */
+    public KeyLoadingException() {
+    }
+
+    /**
+     * Creates a new instance of {@code KeyLoadingException} with the specified detail message.
+     *
+     * @param message the detail message
+     */
+    public KeyLoadingException(String message) {
+        super(message);
+    }
+
+    /**
+     * Creates a new instance of {@code KeyLoadingException} with the specified detail message
+     * and cause.
+     *
+     * @param message the detail message
+     * @param cause   the cause of this exception
+     */
+    public KeyLoadingException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    /**
+     * Creates a new instance of {@code KeyLoadingException} with the specified cause.
+     *
+     * @param cause the cause of this exception
+     */
+    public KeyLoadingException(Throwable cause) {
+        super(cause);
+    }
+
+    /**
+     * Constructs a new exception with the specified detail message, cause, suppression enabled
+     * or disabled, and writable stack trace enabled or disabled.
+     *
+     * @param message the detail message
+     * @param cause the cause of this exception
+     * @param enableSuppression whether suppression is enabled or disabled
+     * @param writableStackTrace whether the stack trace should be writable
+     */
+    public KeyLoadingException(String message,
+                               Throwable cause,
+                               boolean enableSuppression,
+                               boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}
diff --git a/simple-jwt-jjwt/src/main/resources/logback.xml b/key-pair-loader/src/main/resources/logback.xml
similarity index 97%
rename from simple-jwt-jjwt/src/main/resources/logback.xml
rename to key-pair-loader/src/main/resources/logback.xml
index f229a7e..1cf5a50 100644
--- a/simple-jwt-jjwt/src/main/resources/logback.xml
+++ b/key-pair-loader/src/main/resources/logback.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-  ~ Copyright (C) 2023 CodeCraftersCN.
+  ~ Copyright (C) 2024-2024 OnixByte.
   ~
   ~ Licensed under the Apache License, Version 2.0 (the "License");
   ~ you may not use this file except in compliance with the License.
diff --git a/key-pair-loader/src/test/java/com/onixbyte/security/KeyPairLoaderTest.java b/key-pair-loader/src/test/java/com/onixbyte/security/KeyPairLoaderTest.java
new file mode 100644
index 0000000..edfc670
--- /dev/null
+++ b/key-pair-loader/src/test/java/com/onixbyte/security/KeyPairLoaderTest.java
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.security;
+
+import org.junit.jupiter.api.Test;
+
+public class KeyPairLoaderTest {
+
+    @Test
+    public void test() {
+
+    }
+
+}
diff --git a/map-util-unsafe/build.gradle.kts b/map-util-unsafe/build.gradle.kts
new file mode 100644
index 0000000..3376b22
--- /dev/null
+++ b/map-util-unsafe/build.gradle.kts
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.net.URI
+
+val buildGroupId: String by project
+val buildVersion: String by project
+val projectUrl: String by project
+val projectGithubUrl: String by project
+val licenseName: String by project
+val licenseUrl: String by project
+
+group = buildGroupId
+version = buildVersion
+
+dependencies {
+    implementation(project(":devkit-core"))
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+    withSourcesJar()
+    withJavadocJar()
+}
+
+tasks.test {
+    useJUnitPlatform()
+}
+
+publishing {
+    publications {
+        create<MavenPublication>("mapUtilUnsafe") {
+            groupId = buildGroupId
+            artifactId = "map-util-unsafe"
+            version = buildVersion
+
+            pom {
+                name = "Unsafe Map Util"
+                description =
+                    "This module is a converter that can convert an object to a map with unsafe methods."
+                url = projectUrl
+
+                licenses {
+                    license {
+                        name = licenseName
+                        url = licenseUrl
+                    }
+                }
+
+                scm {
+                    connection = "scm:git:git://github.com:OnixByte/JDevKit.git"
+                    developerConnection = "scm:git:git://github.com:OnixByte/JDevKit.git"
+                    url = projectGithubUrl
+                }
+
+                developers {
+                    developer {
+                        id = "zihluwang"
+                        name = "Zihlu Wang"
+                        email = "really@zihlu.wang"
+                        timezone = "Asia/Hong_Kong"
+                    }
+                }
+            }
+
+            from(components["java"])
+
+            signing {
+                sign(publishing.publications["mapUtilUnsafe"])
+            }
+        }
+
+        repositories {
+            maven {
+                name = "sonatypeNexus"
+                url = URI(providers.gradleProperty("repo.maven-central.host").get())
+                credentials {
+                    username = providers.gradleProperty("repo.maven-central.username").get()
+                    password = providers.gradleProperty("repo.maven-central.password").get()
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/unsafe/ReflectMapUtil.java b/map-util-unsafe/src/main/java/com/onixbyte/devkit/utils/unsafe/ReflectMapUtil.java
similarity index 98%
rename from devkit-utils/src/main/java/com/onixbyte/devkit/utils/unsafe/ReflectMapUtil.java
rename to map-util-unsafe/src/main/java/com/onixbyte/devkit/utils/unsafe/ReflectMapUtil.java
index 11815ed..daa84c5 100644
--- a/devkit-utils/src/main/java/com/onixbyte/devkit/utils/unsafe/ReflectMapUtil.java
+++ b/map-util-unsafe/src/main/java/com/onixbyte/devkit/utils/unsafe/ReflectMapUtil.java
@@ -53,7 +53,7 @@ public static Map<String, Object> objectToMap(Object obj) throws IllegalAccessEx
         var declaredFields = obj.getClass().getDeclaredFields();
         for (var field : declaredFields) {
             field.setAccessible(true);
-            Object result = field.get(obj);
+            var result = field.get(obj);
             if (result != null) {
                 map.put(field.getName(), result);
             }
@@ -157,7 +157,8 @@ public static <T> T getFieldValue(Object obj, String fieldName, Class<T> fieldTy
      * @throws IllegalAccessException    if an error occurs while accessing the field
      * @throws NoSuchMethodException     if the specific setter is not present
      */
-    public static void setFieldValue(Object obj, String fieldName, Object fieldValue) throws InvocationTargetException, IllegalAccessException, NoSuchMethodException {
+    public static void setFieldValue(Object obj, String fieldName, Object fieldValue)
+            throws InvocationTargetException, IllegalAccessException, NoSuchMethodException {
         var objectClass = obj.getClass();
         var methodName = getMethodName("set", fieldName);
         var method = objectClass.getDeclaredMethod(methodName, fieldValue.getClass());
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 1e3dd3e..d39293c 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -20,12 +20,11 @@ rootProject.name = "JDevKit"
 include(
     "devkit-core",
     "devkit-utils",
+    "map-util-unsafe",
     "guid",
-    "webcal",
+    "key-pair-loader",
     "simple-jwt-facade",
     "simple-jwt-authzero",
-    "simple-jwt-jjwt",
     "simple-jwt-spring-boot-starter",
     "property-guard-spring-boot-starter"
 )
-include("map-util-unsafe")
diff --git a/simple-jwt-authzero/build.gradle.kts b/simple-jwt-authzero/build.gradle.kts
index b6f85b3..55a62ea 100644
--- a/simple-jwt-authzero/build.gradle.kts
+++ b/simple-jwt-authzero/build.gradle.kts
@@ -33,6 +33,7 @@ version = buildVersion
 dependencies {
     implementation(project(":devkit-utils"))
     implementation(project(":guid"))
+    implementation(project(":key-pair-loader"))
     implementation(project(":simple-jwt-facade"))
     implementation("com.fasterxml.jackson.core:jackson-databind:$jacksonVersion")
     implementation("com.auth0:java-jwt:$javaJwtVersion")
diff --git a/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/AuthzeroTokenResolver.java b/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/AuthzeroTokenResolver.java
index da627b5..8e6b308 100644
--- a/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/AuthzeroTokenResolver.java
+++ b/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/AuthzeroTokenResolver.java
@@ -19,12 +19,11 @@
 
 import com.onixbyte.devkit.utils.Base64Util;
 import com.onixbyte.guid.GuidCreator;
-import com.onixbyte.simplejwt.SecretCreator;
+import com.onixbyte.security.KeyLoader;
 import com.onixbyte.simplejwt.TokenPayload;
 import com.onixbyte.simplejwt.TokenResolver;
 import com.onixbyte.simplejwt.annotations.ExcludeFromPayload;
 import com.onixbyte.simplejwt.annotations.TokenEnum;
-import com.onixbyte.simplejwt.authzero.config.AuthzeroTokenResolverConfig;
 import com.onixbyte.simplejwt.constants.PredefinedKeys;
 import com.onixbyte.simplejwt.constants.TokenAlgorithm;
 import com.auth0.jwt.JWT;
@@ -36,24 +35,29 @@
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.onixbyte.simplejwt.exceptions.IllegalKeyPairException;
+import com.onixbyte.simplejwt.exceptions.IllegalSecretException;
+import com.onixbyte.simplejwt.exceptions.UnsupportedAlgorithmException;
 import lombok.extern.slf4j.Slf4j;
 
 import java.lang.reflect.InvocationTargetException;
+import java.security.interfaces.ECPrivateKey;
+import java.security.interfaces.ECPublicKey;
 import java.time.Duration;
 import java.time.LocalDateTime;
 import java.time.ZoneId;
 import java.util.*;
+import java.util.function.BiFunction;
+import java.util.function.Function;
 
 /**
- * The {@code AuthzeroTokenResolver} class is an implementation of the {@link
- * TokenResolver} interface. It uses the {@code
- * com.auth0:java-jwt} library to handle JSON Web Token (JWT) resolution. This
- * resolver provides functionality to create, extract, verify, and renew JWT
+ * The {@code AuthzeroTokenResolver} class is an implementation of the {@link TokenResolver}
+ * interface. It uses the {@code com.auth0:java-jwt} library to handle JSON Web Token (JWT)
+ * resolution. This resolver provides functionality to create, extract, verify, and renew JWT
  * tokens using various algorithms and custom payload data.
  * <p>
  * <b>Usage:</b>
- * To use the {@code AuthzeroTokenResolver}, first, create an instance of this
- * class:
+ * To use the {@code AuthzeroTokenResolver}, first, create an instance of this class:
  * <pre>{@code
  * TokenResolver<DecodedJWT> tokenResolver =
  *     new AuthzeroTokenResolver(TokenAlgorithm.HS256,
@@ -62,8 +66,7 @@
  *                               "Token Secret");
  * }</pre>
  * <p>
- * Then, you can utilize the various methods provided by this resolver to
- * handle JWT tokens:
+ * Then, you can utilize the various methods provided by this resolver to handle JWT tokens:
  * <pre>{@code
  * // Creating a new JWT token
  * String token =
@@ -82,10 +85,9 @@
  * }</pre>
  * <p>
  * <b>Note:</b>
- * It is essential to configure the appropriate algorithms, secret, and issuer
- * according to your specific use case when using this resolver.
- * Additionally, ensure that the {@code com.auth0:java-jwt} library is
- * correctly configured in your project's dependencies.
+ * It is essential to configure the appropriate algorithms, secret, and issuer according to your
+ * specific use case when using this resolver. Additionally, ensure that the
+ * {@code com.auth0:java-jwt} library is correctly configured in your project's dependencies.
  *
  * @author Zihlu Wang
  * @version 1.1.1
@@ -100,95 +102,160 @@
 public class AuthzeroTokenResolver implements TokenResolver<DecodedJWT> {
 
     /**
-     * Creates a new instance of {@code AuthzeroTokenResolver} with the
-     * provided configurations.
+     * Create a builder of {@link AuthzeroTokenResolver}.
      *
-     * @param jtiCreator   the {@link GuidCreator} used for generating unique
-     *                     identifiers for "jti" claim in JWT tokens
-     * @param algorithm    the algorithm used for signing and verifying JWT
-     *                     tokens
-     * @param issuer       the issuer claim value to be included in JWT tokens
-     * @param secret       the secret used for HMAC-based algorithms (HS256,
-     *                     HS384, HS512) for token signing and verification
-     * @param objectMapper JSON handler
+     * @return a builder instance
      */
-    public AuthzeroTokenResolver(GuidCreator<?> jtiCreator, TokenAlgorithm algorithm, String issuer, String secret, ObjectMapper objectMapper) {
-        if (secret == null || secret.isBlank()) {
-            throw new IllegalArgumentException("A secret is required to build a JSON Web Token.");
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    /**
+     * Builder for {@link AuthzeroTokenResolver}
+     */
+    public static class Builder {
+
+        /**
+         * GuidCreator used for generating unique identifiers for "jti" claim in JWT tokens.
+         */
+        private GuidCreator<?> jtiCreator;
+
+        /**
+         * The algorithm used for signing and verifying JWT tokens.
+         */
+        private Algorithm algorithm;
+
+        /**
+         * The issuer claim value to be included in JWT tokens.
+         */
+        private String issuer;
+
+        /**
+         * Jackson JSON handler.
+         */
+        private ObjectMapper objectMapper;
+
+        /**
+         * The secret to sign a JWT with HMAC based algorithm.
+         */
+        private String secret;
+
+        /**
+         * The private key to sign a JWT with ECDSA based algorithm.
+         */
+        private ECPrivateKey privateKey;
+
+        /**
+         * The public key to read a JWT with ECDSA based algorithm.
+         */
+        private ECPublicKey publicKey;
+
+        /**
+         * Private constructor prevents this class being initialised at somewhere it should not
+         * be initialised.
+         */
+        private Builder() {
         }
 
-        if (secret.length() < 32) {
-            log.warn("The provided secret which owns {} characters is too weak. Please consider replacing it with a stronger one.", secret.length());
+        /**
+         * Set the secret to sign a JWT.
+         *
+         * @param secret the secret
+         * @return the builder instance
+         */
+        public Builder secret(String secret) {
+            this.secret = secret;
+            return this;
         }
 
-        this.jtiCreator = jtiCreator;
-        this.algorithm = config
-                .getAlgorithm(algorithm)
-                .apply(secret);
-        this.issuer = issuer;
-        this.verifier = JWT.require(this.algorithm).build();
-        this.objectMapper = objectMapper;
-    }
+        /**
+         * Set the key pair to sign a JWT.
+         *
+         * @param publicKey  the pem formatted public key text
+         * @param privateKey the pem formatted private key text
+         * @return the builder instance
+         */
+        public Builder keyPair(String publicKey, String privateKey) {
+            this.publicKey = KeyLoader.loadEcdsaPublicKey(publicKey);
+            this.privateKey = KeyLoader.loadEcdsaPrivateKey(privateKey);
+            return this;
+        }
 
-    /**
-     * Creates a new instance of {@link AuthzeroTokenResolver} with the
-     * provided configurations and a simple UUID GuidCreator.
-     *
-     * @param algorithm    the algorithm used for signing and verifying JWT tokens
-     * @param issuer       the issuer claim value to be included in JWT tokens
-     * @param secret       the secret used for HMAC-based algorithms (HS256,
-     *                     HS384, HS512) for token signing and verification
-     * @param objectMapper Jackson Databind JSON Handler
-     */
-    public AuthzeroTokenResolver(TokenAlgorithm algorithm, String issuer, String secret, ObjectMapper objectMapper) {
-        this(UUID::randomUUID, algorithm, issuer, secret, objectMapper);
-    }
+        /**
+         * Set the algorithm to sign a JWT.
+         * <p>
+         * A secret required by HMAC-based algorithms, or key pair required by ECDSA-based
+         * algorithms need to be set before initialise an algorithm.
+         *
+         * @param algorithm an {@link TokenAlgorithm} value
+         * @return the builder instance
+         */
+        public Builder algorithm(TokenAlgorithm algorithm) {
+            // check the secret or key pair before algorithm initialised
+            if (HMAC_ALGORITHMS.containsKey(algorithm)) {
+                if (Objects.isNull(secret) || secret.isBlank()) {
+                    throw new IllegalSecretException("""
+                            Please specify a secret before define an algorithm.""");
+                }
+            } else if (ECDSA_ALGORITHMS.containsKey(algorithm)) {
+                if (Objects.isNull(publicKey) || Objects.isNull(privateKey)) {
+                    throw new IllegalKeyPairException("""
+                            Please specify a ECDSA key pair before define an algorithm.""");
+                }
+            }
 
-    /**
-     * Creates a new instance of {@link AuthzeroTokenResolver} with the
-     * provided configurations and a simple UUID GuidCreator.
-     *
-     * @param algorithm the algorithm used for signing and verifying JWT tokens
-     * @param issuer    the issuer claim value to be included in JWT tokens
-     * @param secret    the secret used for HMAC-based algorithms (HS256,
-     *                  HS384, HS512) for token signing and verification
-     */
-    public AuthzeroTokenResolver(TokenAlgorithm algorithm, String issuer, String secret) {
-        this(UUID::randomUUID, algorithm, issuer, secret, new ObjectMapper());
-    }
+            // initialise algorithm
+            this.algorithm = switch (algorithm) {
+                case HS256, HS384, HS512 -> HMAC_ALGORITHMS.get(algorithm).apply(secret);
+                case ES256, ES384, ES512 -> ECDSA_ALGORITHMS.get(algorithm)
+                        .apply(publicKey, privateKey);
+                default -> throw new UnsupportedAlgorithmException("""
+                        This algorithm is not supported yet.""");
+            };
+            return this;
+        }
 
-    /**
-     * Creates a new instance of {@link AuthzeroTokenResolver} with the
-     * provided configurations, HMAC256 algorithm and a simple
-     * UUID GuidCreator.
-     *
-     * @param issuer the issuer claim value to be included in JWT tokens
-     * @param secret the secret used for HMAC-based algorithms (HS256,
-     *               HS384, HS512) for token signing and verification
-     */
-    public AuthzeroTokenResolver(String issuer, String secret) {
-        this(UUID::randomUUID, TokenAlgorithm.HS256, issuer, secret, new ObjectMapper());
-    }
+        /**
+         * Set the object mapper.
+         *
+         * @param objectMapper an object mapper
+         * @return the builder instance
+         */
+        public Builder objectMapper(ObjectMapper objectMapper) {
+            this.objectMapper = objectMapper;
+            return this;
+        }
 
-    /**
-     * Creates a new instance of {@link AuthzeroTokenResolver} with the
-     * provided configurations, HMAC256 algorithm and a simple
-     * UUID GuidCreator.
-     *
-     * @param issuer the issuer claim value to be included in JWT tokens
-     */
-    public AuthzeroTokenResolver(String issuer) {
-        var secret = SecretCreator.createSecret(32, true, true, true);
+        /**
+         * Set the creator of JWT id.
+         *
+         * @param jtiCreator a creator to create JWT id
+         * @return the builder instance
+         */
+        public Builder jtiCreator(GuidCreator<?> jtiCreator) {
+            this.jtiCreator = jtiCreator;
+            return this;
+        }
 
-        this.jtiCreator = UUID::randomUUID;
-        this.algorithm = config
-                .getAlgorithm(TokenAlgorithm.HS256)
-                .apply(secret);
-        this.issuer = issuer;
-        this.verifier = JWT.require(this.algorithm).build();
-        this.objectMapper = new ObjectMapper();
+        /**
+         * Set the issuer of created JWT.
+         *
+         * @param issuer the person or organisation issued this JWT
+         * @return the builder instance
+         */
+        public Builder issuer(String issuer) {
+            this.issuer = issuer;
+            return this;
+        }
 
-        log.info("The secret has been set to {}.", secret);
+        /**
+         * Create an {@link AuthzeroTokenResolver} instance
+         *
+         * @return created instance
+         */
+        public AuthzeroTokenResolver build() {
+            return new AuthzeroTokenResolver(jtiCreator, algorithm, issuer, objectMapper);
+        }
     }
 
     /**
@@ -239,7 +306,7 @@ public String createToken(Duration expireAfter, String audience, String subject,
      */
     @Override
     public <T extends TokenPayload> String createToken(Duration expireAfter, String audience, String subject, T payload) {
-        final JWTCreator.Builder builder = JWT.create();
+        final var builder = JWT.create();
         buildBasicInfo(builder, expireAfter, subject, audience);
 
         var payloadClass = payload.getClass();
@@ -282,7 +349,7 @@ public <T extends TokenPayload> String createToken(Duration expireAfter, String
      */
     @Override
     public DecodedJWT resolve(String token) {
-        return verifier.verify(token);
+        return jwtVerifier.verify(token);
     }
 
     /**
@@ -438,15 +505,15 @@ private void buildBasicInfo(JWTCreator.Builder builder, Duration expireAfter, St
         // bind issuer (iss)
         builder.withIssuer(issuer);
         // bind issued at (iat)
-        builder.withIssuedAt(Date.from(now.atZone(ZoneId.systemDefault()).toInstant()));
+        builder.withIssuedAt(now.atZone(ZoneId.systemDefault()).toInstant());
         // bind not before (nbf)
-        builder.withNotBefore(Date.from(now.atZone(ZoneId.systemDefault()).toInstant()));
+        builder.withNotBefore(now.atZone(ZoneId.systemDefault()).toInstant());
         // bind audience (aud)
         builder.withAudience(audience);
         // bind subject (sub)
         builder.withSubject(subject);
         // bind expire at (exp)
-        builder.withExpiresAt(Date.from(now.plus(expireAfter).atZone(ZoneId.systemDefault()).toInstant()));
+        builder.withExpiresAt(now.plus(expireAfter).atZone(ZoneId.systemDefault()).toInstant());
         // bind JWT Id (jti)
         builder.withJWTId(jtiCreator.nextId().toString());
     }
@@ -522,14 +589,13 @@ private String buildToken(JWTCreator.Builder builder) {
     /**
      * Default type reference for Map.
      */
-    private static class MapTypeReference extends TypeReference<Map<String, Object>> {
+    public static class MapTypeReference extends TypeReference<Map<String, Object>> {
         MapTypeReference() {
         }
     }
 
     /**
-     * GuidCreator used for generating unique identifiers for "jti" claim in
-     * JWT tokens.
+     * GuidCreator used for generating unique identifiers for "jti" claim in JWT tokens.
      */
     private final GuidCreator<?> jtiCreator;
 
@@ -546,12 +612,45 @@ private static class MapTypeReference extends TypeReference<Map<String, Object>>
     /**
      * The JSON Web Token resolver.
      */
-    private final JWTVerifier verifier;
+    private final JWTVerifier jwtVerifier;
 
     /**
      * Jackson JSON handler.
      */
     private final ObjectMapper objectMapper;
 
-    private final AuthzeroTokenResolverConfig config = AuthzeroTokenResolverConfig.getInstance();
+    /**
+     * A map contains all HMAC-SHA based algorithms.
+     */
+    public static final Map<TokenAlgorithm, Function<String, Algorithm>> HMAC_ALGORITHMS = Map.of(
+            TokenAlgorithm.HS256, Algorithm::HMAC256,
+            TokenAlgorithm.HS384, Algorithm::HMAC384,
+            TokenAlgorithm.HS512, Algorithm::HMAC512
+    );
+
+    /**
+     * A map contains all ECDSA based algorithms.
+     */
+    public static final Map<TokenAlgorithm, BiFunction<ECPublicKey, ECPrivateKey, Algorithm>> ECDSA_ALGORITHMS = Map.of(
+            TokenAlgorithm.ES256, Algorithm::ECDSA256,
+            TokenAlgorithm.ES384, Algorithm::ECDSA384,
+            TokenAlgorithm.ES512, Algorithm::ECDSA512
+    );
+
+    /**
+     * Private constructor prevent this class being initialised mistakenly.
+     *
+     * @param jtiCreator   a creator that can create JWT id
+     * @param algorithm    an algorithm to sign this JWT
+     * @param issuer       the person or organisation who issued this JWT
+     * @param objectMapper a mapper for handling JSON serialisation and deserialization
+     */
+    private AuthzeroTokenResolver(GuidCreator<?> jtiCreator, Algorithm algorithm, String issuer, ObjectMapper objectMapper) {
+        this.jtiCreator = jtiCreator;
+        this.algorithm = algorithm;
+        this.issuer = issuer;
+        this.objectMapper = objectMapper;
+        this.jwtVerifier = JWT.require(algorithm).build();
+    }
+
 }
diff --git a/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/config/AuthzeroTokenResolverConfig.java b/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/config/AuthzeroTokenResolverConfig.java
deleted file mode 100644
index b153c23..0000000
--- a/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/config/AuthzeroTokenResolverConfig.java
+++ /dev/null
@@ -1,143 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.onixbyte.simplejwt.authzero.config;
-
-import com.onixbyte.simplejwt.TokenResolver;
-import com.onixbyte.simplejwt.authzero.AuthzeroTokenResolver;
-import com.onixbyte.simplejwt.config.TokenResolverConfig;
-import com.onixbyte.simplejwt.constants.TokenAlgorithm;
-import com.onixbyte.simplejwt.exceptions.UnsupportedAlgorithmException;
-import com.auth0.jwt.algorithms.Algorithm;
-
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.function.Function;
-
-/**
- * The {@code AuthzeroTokenResolverConfig} class provides the configuration for
- * the {@link AuthzeroTokenResolver}.
- * <p>
- * This configuration is used to establish the mapping between the standard
- * {@link TokenAlgorithm} defined in the
- * {@code cn.org.codecrafters:simple-jwt-facade} and the specific algorithms
- * used by the {@code com.auth0:java-jwt} library, which is the underlying
- * library used by {@link AuthzeroTokenResolver} to handle JSON Web Tokens
- * (JWTs).
- * <p>
- * <b>Algorithm Mapping:</b>
- * The {@code AuthzeroTokenResolverConfig} allows specifying the relationships
- * between the standard {@link TokenAlgorithm} instances supported by
- * {@link AuthzeroTokenResolver} and the corresponding algorithms used by the
- * {@code com.auth0:java-jwt} library. The mapping is achieved using a Map,
- * where the keys are the standard {@link TokenAlgorithm} instances, and the
- * values represent the algorithm functions used by {@code com.auth0:java-jwt}
- * library for each corresponding key.
- * <p>
- * <b>Note:</b>
- * The provided algorithm mapping should be consistent with the actual
- * algorithms supported and used by the {@code com.auth0:java-jwt} library. It
- * is crucial to ensure that the mapping is accurate to enable proper token
- * validation and processing within the {@link AuthzeroTokenResolver}.
- *
- * @author Zihlu Wang
- * @version 1.1.1
- * @since 1.0.0
- */
-public final class AuthzeroTokenResolverConfig implements TokenResolverConfig<Function<String, Algorithm>> {
-
-    /**
-     * Gets the instance of {@code AuthzeroTokenResolverConfig}.
-     * <p>
-     * This method returns the singleton instance of
-     * {@code AuthzeroTokenResolverConfig}. If the instance is not yet created,
-     * it will create a new instance and return it. Otherwise, it returns the
-     * existing instance.
-     *
-     * @return the instance of {@code AuthzeroTokenResolverConfig}
-     */
-    public static AuthzeroTokenResolverConfig getInstance() {
-        if (Objects.isNull(instance)) {
-            instance = new AuthzeroTokenResolverConfig();
-        }
-
-        return instance;
-    }
-
-    /**
-     * Gets the algorithm function corresponding to the specified
-     * {@link TokenAlgorithm}.
-     * <p>
-     * This method returns the algorithm function associated with the given
-     * {@link TokenAlgorithm}. The provided {@link TokenAlgorithm} represents
-     * the specific algorithm for which the corresponding algorithm function
-     * is required. The returned Algorithm Function represents the function
-     * implementation that can be used by the {@link TokenResolver} to handle
-     * the specific algorithm.
-     *
-     * @param algorithm the {@link TokenAlgorithm} for which the algorithm
-     *                  function isrequired
-     * @return the algorithm function associated with the given {@link
-     * TokenAlgorithm}
-     * @throws UnsupportedAlgorithmException if the given {@code algorithm} is
-     *                                       not supported by this
-     *                                       implementation
-     */
-    @Override
-    public Function<String, Algorithm> getAlgorithm(TokenAlgorithm algorithm) {
-        return Optional.of(SUPPORTED_ALGORITHMS).map((entry) -> entry.get(algorithm))
-                .orElseThrow(() -> new UnsupportedAlgorithmException("The specified algorithm is not supported yet."));
-    }
-
-    /**
-     * Constructs a new instance of {@code AuthzeroTokenResolverConfig}.
-     * <p>
-     * The constructor is set as private to enforce the singleton pattern for
-     * this configuration class. Instances of
-     * {@code AuthzeroTokenResolverConfig} should be obtained through the
-     * {@link #getInstance()} method.
-     */
-    private AuthzeroTokenResolverConfig() {
-    }
-
-    /**
-     * The singleton instance of {@code AuthzeroTokenResolverConfig}.
-     * <p>
-     * This instance is used to ensure that only one instance of
-     * {@code AuthzeroTokenResolverConfig} is created and shared throughout the
-     * application. The singleton pattern is implemented to provide centralised
-     * configuration and avoid redundant object creation.
-     */
-    private static AuthzeroTokenResolverConfig instance;
-
-    /**
-     * The supported algorithms and their corresponding algorithm functions.
-     * <p>
-     * This map stores the supported algorithms as keys and their corresponding
-     * algorithm functions as values. The algorithm functions represent the
-     * functions used by the {@code com.auth0:java-jwt} library to handle the
-     * specific algorithms. The mapping is used to provide proper algorithm
-     * resolution and processing within the {@link AuthzeroTokenResolver}.
-     */
-    private static final Map<TokenAlgorithm, Function<String, Algorithm>> SUPPORTED_ALGORITHMS = new HashMap<>() {{
-        put(TokenAlgorithm.HS256, Algorithm::HMAC256);
-        put(TokenAlgorithm.HS384, Algorithm::HMAC384);
-        put(TokenAlgorithm.HS512, Algorithm::HMAC512);
-    }};
-}
diff --git a/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/config/package-info.java b/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/config/package-info.java
deleted file mode 100644
index 1461f12..0000000
--- a/simple-jwt-authzero/src/main/java/com/onixbyte/simplejwt/authzero/config/package-info.java
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * The package {@code cn.org.codecrafters.simplejwt.authzero.config} contains
- * configuration classes related to the {@link
- * com.onixbyte.simplejwt.authzero.AuthzeroTokenResolver}
- * implementation.
- * <p>
- * The classes in this package provide configuration options and settings for
- * the {@link com.onixbyte.simplejwt.authzero.AuthzeroTokenResolver},
- * which is used for resolving JSON Web Tokens (JWT) using the Auth0 library.
- * <p>
- * The {@link
- * com.onixbyte.simplejwt.authzero.config.AuthzeroTokenResolverConfig}
- * class is a configuration class that defines the mapping between standard
- * {@link com.onixbyte.simplejwt.constants.TokenAlgorithm} and the
- * corresponding function implementation used by {@link
- * com.onixbyte.simplejwt.authzero.AuthzeroTokenResolver} for handling
- * JWT algorithms. It enables developers to specify and customize the
- * algorithm functions according to the chosen JWT algorithm and the library
- * being used.
- * <p>
- * The configuration options in this package help developers integrate and
- * configure the {@link
- * com.onixbyte.simplejwt.authzero.AuthzeroTokenResolver} seamlessly
- * into their Spring Boot applications. Developers can fine-tune the token
- * resolution process and customize algorithm handling to align with their
- * specific requirements and desired level of security.
- * <p>
- * It is recommended to explore the classes in this package to understand how
- * to configure and use the {@link
- * com.onixbyte.simplejwt.authzero.AuthzeroTokenResolver} effectively
- * in the Spring Boot environment to handle JWT authentication and
- * authorisation securely and efficiently.
- *
- * @since 1.0.0
- */
-
-package com.onixbyte.simplejwt.authzero.config;
\ No newline at end of file
diff --git a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/config/TokenResolverConfig.java b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/config/TokenResolverConfig.java
deleted file mode 100644
index 2252563..0000000
--- a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/config/TokenResolverConfig.java
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.onixbyte.simplejwt.config;
-
-import com.onixbyte.simplejwt.TokenResolver;
-import com.onixbyte.simplejwt.constants.TokenAlgorithm;
-
-/**
- * The {@code TokenResolverConfig} provides a mechanism to configure an
- * implementation of {@link TokenResolver} with algorithm functions.
- * <p>
- * This generic interface is used to define the configuration details for a
- * {@link TokenResolver} that utilizes algorithm functions. The interface
- * allows for specifying algorithm functions corresponding to different {@link
- * TokenAlgorithm} instances supported by the {@link TokenResolver}
- * implementation.
- *
- * @param <Algo> the type representing algorithm functions used by the
- *               {@link TokenResolver}
- * @author Zihlu Wang
- * @version 1.0.0
- * @since 1.0.0
- */
-public interface TokenResolverConfig<Algo> {
-
-    /**
-     * Gets the algorithm function corresponding to the specified {@link
-     * TokenAlgorithm}.
-     * <p>
-     * This method returns the algorithm function associated with the given
-     * {@link TokenAlgorithm}. The provided TokenAlgorithm represents the
-     * specific algorithm for which the corresponding algorithm function is
-     * required. The returned {@code Algo} represents the function
-     * implementation that can be used by the {@link TokenResolver} to handle
-     * the specific algorithm.
-     *
-     * @param algorithm the {@link TokenAlgorithm} for which the algorithm
-     *                  function is required
-     * @return the algorithm function associated with the given {@link
-     * TokenAlgorithm}
-     */
-    Algo getAlgorithm(TokenAlgorithm algorithm);
-
-}
diff --git a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/config/package-info.java b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/config/package-info.java
deleted file mode 100644
index 4ddf654..0000000
--- a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/config/package-info.java
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * The classes in this package provide configuration options and settings for
- * the {@code cn.org.codecrafters:simple-jwt-facade} library. They are used
- * to customize the behavior of the library and allow developers to fine-tune
- * various aspects of JWT generation and validation.
- * <p>
- * Other configuration classes may be added in the future to support additional
- * customisation options and features. Developers using the
- * {@code cn.org.codecrafters:simple-jwt-facade} library should be familiar
- * with the available configuration options to ensure proper integration and
- * usage of the library.
- *
- * @since 1.0.0
- */
-package com.onixbyte.simplejwt.config;
\ No newline at end of file
diff --git a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/constants/PredefinedKeys.java b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/constants/PredefinedKeys.java
index 0a9bdb5..c531d56 100644
--- a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/constants/PredefinedKeys.java
+++ b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/constants/PredefinedKeys.java
@@ -35,13 +35,14 @@
  *     <li>{@link #JWT_ID}: Represents the "jti" (JWT ID) claim.</li>
  * </ul>
  * <p>
- * The class also contains a list of all the standard claim constants, accessible via the {@link #KEYS} field. This
- * list can be useful for iterating through all the standard claims or checking for the presence of specific claims.
+ * The class also contains a list of all the standard claim constants, accessible via the {@link
+ * #KEYS} field. This list can be useful for iterating through all the standard claims or checking
+ * for the presence of specific claims.
  * <p>
- * Note: This class is final and cannot be instantiated. It only serves as a utility class to hold the standard JWT
- * claim constants.
+ * Note: This class is final and cannot be instantiated. It only serves as a utility class to hold
+ * the standard JWT claim constants.
  *
- * @author Zihlu Wang
+ * @author zihluwang
  * @version 1.1.0
  * @since 1.0.0
  */
@@ -85,7 +86,8 @@ public final class PredefinedKeys {
     /**
      * List containing all the standard JWT claim constants.
      */
-    public static final List<String> KEYS = List.of(ISSUER, SUBJECT, AUDIENCE, EXPIRATION_TIME, NOT_BEFORE, ISSUED_AT, JWT_ID);
+    public static final List<String> KEYS =
+            List.of(ISSUER, SUBJECT, AUDIENCE, EXPIRATION_TIME, NOT_BEFORE, ISSUED_AT, JWT_ID);
 
     /**
      * Private constructor will protect this class from being instantiated.
diff --git a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/constants/TokenAlgorithm.java b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/constants/TokenAlgorithm.java
index 10eec52..a0dc86b 100644
--- a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/constants/TokenAlgorithm.java
+++ b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/constants/TokenAlgorithm.java
@@ -19,6 +19,8 @@
 
 import lombok.Getter;
 
+import java.util.List;
+
 /**
  * The {@code TokenAlgorithm} enum class defines the algorithms that can be
  * used for signing and verifying JSON Web Tokens (JWT). JWT allows various
@@ -92,4 +94,18 @@ public enum TokenAlgorithm {
     ES512,
     ;
 
+    /**
+     * HMAC-based algorithms.
+     */
+    public static final List<TokenAlgorithm> HMAC_ALGORITHMS = List.of(
+            TokenAlgorithm.HS256, TokenAlgorithm.HS384, TokenAlgorithm.HS512
+    );
+
+    /**
+     * ECDSA-based algorithms.
+     */
+    public static final List<TokenAlgorithm> ECDSA_ALGORITHMS = List.of(
+            TokenAlgorithm.ES256, TokenAlgorithm.ES384, TokenAlgorithm.ES512
+    );
+
 }
diff --git a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/exceptions/IllegalKeyPairException.java b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/exceptions/IllegalKeyPairException.java
new file mode 100644
index 0000000..0b725dd
--- /dev/null
+++ b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/exceptions/IllegalKeyPairException.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.simplejwt.exceptions;
+
+/**
+ * {@link IllegalKeyPairException} indicates an exception that the key pair is invalid.
+ *
+ * @author zihluwang
+ * @version 1.6.0
+ */
+public class IllegalKeyPairException extends RuntimeException {
+
+    /**
+     * Create a default exception instance.
+     */
+    public IllegalKeyPairException() {
+    }
+
+    /**
+     * Create an exception instance with specific message.
+     *
+     * @param message the message of the exception
+     */
+    public IllegalKeyPairException(String message) {
+        super(message);
+    }
+
+    /**
+     * Create an exception instance with specific message and cause.
+     *
+     * @param message the message of the exception
+     * @param cause   the cause of the exception
+     */
+    public IllegalKeyPairException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+}
diff --git a/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/exceptions/IllegalSecretException.java b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/exceptions/IllegalSecretException.java
new file mode 100644
index 0000000..6722ebd
--- /dev/null
+++ b/simple-jwt-facade/src/main/java/com/onixbyte/simplejwt/exceptions/IllegalSecretException.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.simplejwt.exceptions;
+
+/**
+ * {@link IllegalKeyPairException} indicates the secret to sign a JWT is illegal.
+ *
+ * @author zihluwang
+ * @version 1.6.0
+ * @since 1.6.0
+ */
+public class IllegalSecretException extends RuntimeException {
+
+    /**
+     * Create a default exception instance.
+     */
+    public IllegalSecretException() {
+    }
+
+    /**
+     * Create an exception instance with specific message.
+     *
+     * @param message the message of the exception
+     */
+    public IllegalSecretException(String message) {
+        super(message);
+    }
+
+    /**
+     * Create an exception instance with specific message and the cause of this exception.
+     *
+     * @param message the message of the exception
+     * @param cause   the cause of the exception
+     */
+    public IllegalSecretException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+}
diff --git a/simple-jwt-jjwt/README.md b/simple-jwt-jjwt/README.md
deleted file mode 100644
index 2dd64e1..0000000
--- a/simple-jwt-jjwt/README.md
+++ /dev/null
@@ -1,54 +0,0 @@
-# Module `simple-jwt-jjwt`
-
-## Introduction
-
-The `simple-jwt-jjwt` module is an implementation of module `simple-jwt-facade` which uses the third-party library [`io.jsonwebtoken:jjwt-api`](https://github.com/jwtk/jjwt). By using this module can help you use JWT to help you in your application.
-
-## Prerequisites
-
-This whole `JDevKit` is developed by **JDK 17**, which means you have to use JDK 17 for better experience.
-
-## Installation
-
-> This module has already imported `simple-jwt-facade`, there is no need to import it again.
-
-### If you are using `Maven`
-
-It is quite simple to install this module by `Maven`. The only thing you need to do is find your `pom.xml` file in the project, then find the `<dependencies>` node in the `<project>` node, and add the following codes to `<dependencies>` node:
-
-```xml
-<dependency>
-	<groupId>cn.org.codecrafters</groupId>
-    <artifactId>simple-jwt-jjwt</artifactId>
-    <version>${simple-jwt-jjwt.version}</version>
-</dependency>
-```
-
-And run `mvn dependency:get` in your project root folder(i.e., if your `pom.xml` is located at `/path/to/your/project/pom.xml`, then your current work folder should be `/path/to/your/project`), then `Maven` will automatically download the `jar` archive from `Maven Central Repository`. This could be **MUCH EASIER** if you are using IDE(i.e., IntelliJ IDEA), the only thing you need to do is click the refresh button of `Maven`.
-
-### If you are using `Gradle`
-
-Add this module to your project with `Gradle` is much easier than doing so with `Maven`.
-
-Find `build.gradle` in the needed project, and add the following code to the `dependencies` closure in the build script:
-
-```groovy
-implementation 'cn.org.codecrafters:simple-jwt-authzero:${simple-jwt-authzero.version}'
-```
-
-### If you are not using `Maven` or `Gradle`
-
-1. Download the `jar` file from the Internet.
-2. Create a folder in your project and name it as a name you like(i.e., for me, I prefer `vendor`).
-3. Put the `jar` file to the folder you just created in Step 2.
-4. Add this folder to your project `classpath`.
-
-## Use the `JjwtTokenResolver`
-
-We have implemented `TokenResolver` to make sure you can add JWT to your Java application as soon as possible. All you need to do is to create an instance of `jjwt.com.onixbyte.simplejwt.JjwtTokenResolver` and other operations to JWT could follow our instruction in [`simple-jwt-facade`](../simple-jwt-facade/README.md).
-
-## Contact
-
-If you have any suggestions, ideas, don't hesitate contacting us via [GitHub Issues](https://github.com/CodeCraftersCN/jdevkit/issues/new) or [Discord Community](https://discord.gg/NQK9tjcBB8). 
-
-If you face any bugs while using our library and you are able to fix any bugs in our library, we would be happy to accept pull requests from you on [GitHub](https://github.com/CodeCraftersCN/jdevkit/compare).
diff --git a/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/JjwtTokenResolver.java b/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/JjwtTokenResolver.java
deleted file mode 100644
index 3607631..0000000
--- a/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/JjwtTokenResolver.java
+++ /dev/null
@@ -1,480 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.onixbyte.simplejwt.jjwt;
-
-import com.onixbyte.devkit.utils.MapUtil;
-import com.onixbyte.guid.GuidCreator;
-import com.onixbyte.simplejwt.SecretCreator;
-import com.onixbyte.simplejwt.TokenPayload;
-import com.onixbyte.simplejwt.TokenResolver;
-import com.onixbyte.simplejwt.annotations.ExcludeFromPayload;
-import com.onixbyte.simplejwt.annotations.TokenEnum;
-import com.onixbyte.simplejwt.constants.PredefinedKeys;
-import com.onixbyte.simplejwt.constants.TokenAlgorithm;
-import com.onixbyte.simplejwt.exceptions.WeakSecretException;
-import com.onixbyte.simplejwt.jjwt.config.JjwtTokenResolverConfig;
-import io.jsonwebtoken.Claims;
-import io.jsonwebtoken.Jws;
-import io.jsonwebtoken.Jwts;
-import io.jsonwebtoken.security.Keys;
-import io.jsonwebtoken.security.SecureDigestAlgorithm;
-import lombok.extern.slf4j.Slf4j;
-
-import javax.crypto.SecretKey;
-import java.lang.reflect.InvocationTargetException;
-import java.nio.charset.StandardCharsets;
-import java.time.Duration;
-import java.time.LocalDateTime;
-import java.time.ZoneId;
-import java.util.*;
-
-/**
- * The {@link JjwtTokenResolver} class is an implementation of the {@link
- * TokenResolver} interface. It uses the {@code
- * io.jsonwebtoken:jjwt} library to handle JSON Web Token (JWT) resolution.
- * This resolver provides functionality to create, extract, verify, and renew
- * JWT tokens using various algorithms and custom payload data.
- * <p>
- * <b>Usage:</b>
- * To use the {@code JjwtTokenResolver}, first, create an instance of this
- * class:
- * <pre>{@code
- *   TokenResolver<Jws<Claims>> tokenResolver =
- *       new JjwtTokenResolver(TokenAlgorithm.HS256,
- *                                 "Token Subject",
- *                                 "Token Issuer",
- *                                 "Token Secret");
- *   }</pre>
- * <p>
- * Then, you can utilize the various methods provided by this resolver to
- * handle JWT tokens:
- * <pre>{@code
- *   // Creating a new JWT token
- *   String token =
- *       tokenResolver.createToken(Duration.ofHours(1),
- *                                 "your_subject",
- *                                 "your_audience",
- *                                 customPayloads);
- *
- *   // Extracting payload data from a JWT token
- *   DecodedJWT decodedJWT = tokenResolver.resolve(token);
- *   T payloadData = decodedJWT.extract(token, T.class);
- *
- *   // Renewing an existing JWT token
- *   String renewedToken =
- *       tokenResolver.renew(token, Duration.ofMinutes(30), customPayloads);
- *   }</pre>
- * <p>
- * <b>Note:</b>
- * It is essential to configure the appropriate algorithms, secret, and issuer
- * according to your specific use case when using this resolver.
- * Additionally, ensure that the {@code io.jsonwebtoken:jjwt} library is
- * correctly configured in your project's dependencies.
- *
- * @author Zihlu Wang
- * @version 1.1.0
- * @see Claims
- * @see Jws
- * @see Jwts
- * @see SecureDigestAlgorithm
- * @see Keys
- * @since 1.0.0
- */
-@Slf4j
-public class JjwtTokenResolver implements TokenResolver<Jws<Claims>> {
-
-    /**
-     * Create a resolver with specified algorithm, issuer, secret and guid strategy.
-     *
-     * @param jtiCreator jwt id creator
-     * @param algorithm  specified algorithm
-     * @param issuer     specified issuer
-     * @param secret     specified secret
-     */
-    public JjwtTokenResolver(GuidCreator<?> jtiCreator, TokenAlgorithm algorithm, String issuer, String secret) {
-        if (Objects.isNull(secret) || secret.isBlank()) {
-            throw new IllegalArgumentException("A secret is required to build a JSON Web Token.");
-        }
-
-        if (secret.length() < 32) {
-            log.error("""
-                            The provided secret which owns {} characters is too weak. Please replace it with a stronger one.""",
-                    secret.length());
-            throw new WeakSecretException("""
-                    The provided secret which owns %s characters is too weak. Please replace it with a stronger one."""
-                    .formatted(secret.length()));
-        }
-
-        this.jtiCreator = jtiCreator;
-        this.algorithm = config.getAlgorithm(algorithm);
-        this.issuer = issuer;
-        this.key = Keys.hmacShaKeyFor(secret.getBytes(StandardCharsets.UTF_8));
-    }
-
-    /**
-     * Create a resolver with specified algorithm, issuer, secret and default guid strategy.
-     *
-     * @param algorithm specified algorithm
-     * @param issuer    specified issuer
-     * @param secret    specified secret
-     */
-    public JjwtTokenResolver(TokenAlgorithm algorithm, String issuer, String secret) {
-        if (secret == null || secret.isBlank()) {
-            throw new IllegalArgumentException("A secret is required to build a JSON Web Token.");
-        }
-
-        if (secret.length() < 32) {
-            log.error(
-                    "The provided secret which owns {} characters is too weak. Please replace it with a stronger one.",
-                    secret.length());
-            throw new WeakSecretException(
-                    "The provided secret which owns %s characters is too weak. Please replace it with a stronger one."
-                            .formatted(secret.length()));
-        }
-
-        this.jtiCreator = UUID::randomUUID;
-        this.algorithm = config.getAlgorithm(algorithm);
-        this.issuer = issuer;
-        this.key = Keys.hmacShaKeyFor(secret.getBytes(StandardCharsets.UTF_8));
-    }
-
-    /**
-     * Create a resolver with specified issuer, secret, default algorithm and guid strategy.
-     *
-     * @param issuer specified issuer
-     * @param secret specified secret
-     * @see #JjwtTokenResolver(TokenAlgorithm, String, String)
-     */
-    public JjwtTokenResolver(String issuer, String secret) {
-        if (secret == null || secret.isBlank()) {
-            throw new IllegalArgumentException("A secret is required to build a JSON Web Token.");
-        }
-
-        if (secret.length() < 32) {
-            log.error(
-                    "The provided secret which owns {} characters is too weak. Please replace it with a stronger one.",
-                    secret.length());
-            throw new WeakSecretException(
-                    "The provided secret which owns %s characters is too weak. Please replace it with a stronger one."
-                            .formatted(secret.length()));
-        }
-
-        this.jtiCreator = UUID::randomUUID;
-        this.algorithm = config.getAlgorithm(TokenAlgorithm.HS256);
-        this.issuer = issuer;
-        this.key = Keys.hmacShaKeyFor(secret.getBytes(StandardCharsets.UTF_8));
-    }
-
-    /**
-     * Create a resolver with specified issuer, random secret string, default algorithm and guid strategy.
-     *
-     * @param issuer specified issuer
-     * @see #JjwtTokenResolver(String, String)
-     */
-    public JjwtTokenResolver(String issuer) {
-        this.jtiCreator = UUID::randomUUID;
-        this.algorithm = config.getAlgorithm(TokenAlgorithm.HS256);
-        this.issuer = issuer;
-        this.key = Keys.hmacShaKeyFor(SecretCreator.createSecret(32, true, true, true).getBytes(StandardCharsets.UTF_8));
-    }
-
-    /**
-     * Creates a new token with the specified expiration time, subject, and
-     * audience.
-     *
-     * @param expireAfter the duration after which the token will expire
-     * @param audience    the audience for which the token is intended
-     * @param subject     the subject of the token
-     * @return the generated token as a {@code String}
-     */
-    @Override
-    public String createToken(Duration expireAfter, String audience, String subject) {
-        return buildToken(expireAfter, audience, subject, null);
-    }
-
-    /**
-     * Creates a new token with the specified expiration time, subject,
-     * audience, and custom payload data.
-     *
-     * @param expireAfter the duration after which the token will expire
-     * @param audience    the audience for which the token is intended
-     * @param subject     the subject of the token
-     * @param payload     the custom payload data to be included in the token
-     * @return the generated token as a {@code String}
-     */
-    @Override
-    public String createToken(Duration expireAfter, String audience, String subject, Map<String, Object> payload) {
-        return buildToken(expireAfter, audience, subject, payload);
-    }
-
-    /**
-     * Creates a new token with the specified expiration time, subject,
-     * audience, and strongly-typed payload data.
-     *
-     * @param expireAfter the duration after which the token will expire
-     * @param audience    the audience for which the token is intended
-     * @param subject     the subject of the token
-     * @param payload     the strongly-typed payload data to be included in the
-     *                    token
-     * @return the generated token as a {@code String} or {@code null} if
-     * creation fails
-     * @see MapUtil#objectToMap(Object, Map)
-     */
-    @Override
-    public <T extends TokenPayload> String createToken(Duration expireAfter, String audience, String subject, T payload) {
-        var fields = payload.getClass().getDeclaredFields();
-        var payloadMap = new HashMap<String, Object>();
-
-        for (var field : fields) {
-            if (field.isAnnotationPresent(ExcludeFromPayload.class))
-                continue;
-
-            try {
-                var getter = payload.getClass().getDeclaredMethod("get" + field.getName().substring(0, 1).toUpperCase() + field.getName().substring(1));
-                // Build Claims
-                /*
-                 * Note (17 Oct, 2023): The jjwt can only add a map to be added.
-                 */
-                var fieldValue = getter.invoke(payload);
-
-                // Handle enum fields.
-                if (field.isAnnotationPresent(TokenEnum.class)) {
-                    var annotation = field.getAnnotation(TokenEnum.class);
-                    var enumGetter = field.getType().getDeclaredMethod("get" + annotation.propertyName().substring(0, 1).toUpperCase() + annotation.propertyName().substring(1));
-                    fieldValue = enumGetter.invoke(fieldValue);
-                }
-                payloadMap.put(field.getName(), fieldValue);
-            } catch (IllegalAccessException | NoSuchMethodException e) {
-                log.error("Cannot access field {}!", field.getName());
-            } catch (InvocationTargetException e) {
-                log.error("Cannot invoke getter.", e);
-            }
-        }
-
-        return buildToken(expireAfter, audience, subject, payloadMap);
-    }
-
-    /**
-     * Resolves the given token into a {@link Jws<Claims>} object.
-     *
-     * @param token the token to be resolved
-     * @return a ResolvedTokenType object
-     */
-    @Override
-    public Jws<Claims> resolve(String token) {
-        return Jwts.parser()
-                .verifyWith(key)
-                .build()
-                .parseSignedClaims(token);
-    }
-
-    /**
-     * Extracts the payload information from the given token and maps it to the
-     * specified target type.
-     *
-     * @param token      the token from which to extract the payload
-     * @param targetType the target class representing the payload data type
-     * @return an instance of the specified target type with the extracted
-     * payload data, or {@code null} if extraction fails.
-     * @see MapUtil#mapToObject(Map, Object, Map)
-     */
-    @Override
-    public <T extends TokenPayload> T extract(String token, Class<T> targetType) {
-        var resolvedToken = resolve(token);
-
-        var claims = resolvedToken.getPayload();
-        try {
-            var bean = targetType.getConstructor().newInstance();
-
-            for (var entry : claims.entrySet()) {
-                // Jump all JWT pre-defined properties and the fields that are annotated to be excluded.
-                if (PredefinedKeys.KEYS.contains(entry.getKey()) || targetType.getDeclaredField(entry.getKey()).isAnnotationPresent(ExcludeFromPayload.class))
-                    continue;
-
-                var field = targetType.getDeclaredField(entry.getKey());
-                var fieldValue = entry.getValue();
-                if (field.isAnnotationPresent(TokenEnum.class)) {
-                    var annotation = field.getAnnotation(TokenEnum.class);
-                    var enumStaticLoader = field.getType().getDeclaredMethod("loadBy" + annotation.propertyName().substring(0, 1).toUpperCase() + annotation.propertyName().substring(1), annotation.dataType().getMappedClass());
-                    fieldValue = enumStaticLoader.invoke(null, entry.getValue());
-                }
-
-                var setter = targetType.getDeclaredMethod("set" + entry.getKey().substring(0, 1).toUpperCase() + entry.getKey().substring(1), fieldValue.getClass());
-                if (setter.canAccess(bean)) {
-                    setter.invoke(bean, fieldValue);
-                } else {
-                    log.error("Setter for field {} can't be accessed.", entry.getKey());
-                }
-            }
-
-            return bean;
-        } catch (InvocationTargetException e) {
-            log.error("Target is not invokable.", e);
-        } catch (NoSuchMethodException e) {
-            log.error("Cannot find method according to given data.", e);
-        } catch (InstantiationException e) {
-            log.error("The required type {} is abstract or an interface.", targetType.getCanonicalName());
-        } catch (IllegalAccessException e) {
-            log.error("An error occurs while accessing the fields of the object.", e);
-        } catch (NoSuchFieldException e) {
-            log.error("Cannot load field according to given field name.", e);
-        }
-
-        return null;
-    }
-
-    /**
-     * Re-generate a new token with the payload in the old one.
-     *
-     * @param oldToken    the old token
-     * @param expireAfter how long the new token can be valid for
-     * @return re-generated token with the payload in the old one
-     */
-    @Override
-    public String renew(String oldToken, Duration expireAfter) {
-        var resolvedToken = resolve(oldToken);
-        var tokenPayloads = resolvedToken.getPayload();
-
-        var audience = tokenPayloads.getAudience().toArray(new String[]{})[0];
-        var subject = tokenPayloads.getSubject();
-
-        PredefinedKeys.KEYS.forEach(tokenPayloads::remove);
-
-        return createToken(expireAfter, audience, subject, tokenPayloads);
-    }
-
-    /**
-     * Renews the given expired token with the specified custom payload data.
-     *
-     * @param oldToken    the expired token to be renewed
-     * @param expireAfter specify when does the new token invalid
-     * @param payload     the custom payload data to be included in the renewed
-     *                    token
-     * @return the renewed token as a {@code String}
-     */
-    @Override
-    public String renew(String oldToken, Duration expireAfter, Map<String, Object> payload) {
-        var resolvedTokenClaims = resolve(oldToken).getPayload();
-        var audience = resolvedTokenClaims.getAudience().toArray(new String[]{})[0];
-        var subject = resolvedTokenClaims.getSubject();
-
-        return createToken(expireAfter, audience, subject, payload);
-    }
-
-    /**
-     * Renews the given expired token with the specified custom payload data.
-     *
-     * @param oldToken the expired token to be renewed
-     * @param payload  the custom payload data to be included in the renewed
-     *                 token
-     * @return the renewed token as a {@code String}
-     */
-    @Override
-    public String renew(String oldToken, Map<String, Object> payload) {
-        return renew(oldToken, Duration.ofMinutes(30), payload);
-    }
-
-    /**
-     * Renews the given expired token with the specified strongly-typed
-     * payload data.
-     *
-     * @param oldToken    the expired token to be renewed
-     * @param expireAfter specify when does the new token invalid
-     * @param payload     the strongly-typed payload data to be included in the
-     *                    renewed token
-     * @return the renewed token as a {@code String}
-     */
-    @Override
-    public <T extends TokenPayload> String renew(String oldToken, Duration expireAfter, T payload) {
-        var resolvedTokenClaims = resolve(oldToken).getPayload();
-        var audience = resolvedTokenClaims.getAudience().toArray(new String[]{})[0];
-        var subject = resolvedTokenClaims.getSubject();
-
-        return createToken(expireAfter, audience, subject, payload);
-    }
-
-    /**
-     * Renews the given expired token with the specified strongly-typed
-     * payload data.
-     *
-     * @param oldToken the expired token to be renewed
-     * @param payload  the strongly-typed payload data to be included in the
-     *                 renewed token
-     * @return the renewed token as a {@code String}
-     */
-    @Override
-    public <T extends TokenPayload> String renew(String oldToken, T payload) {
-        return renew(oldToken, Duration.ofMinutes(30), payload);
-    }
-
-    /**
-     * Build a new token with specified data.
-     *
-     * @param expireAfter the validity time of the token
-     * @param audience    the audience of the token
-     * @param subject     the subject of the token
-     * @param claims      the data to be included in the token
-     * @return the built token
-     */
-    private String buildToken(Duration expireAfter, String audience, String subject, Map<String, Object> claims) {
-        var now = LocalDateTime.now();
-        var builder = Jwts.builder()
-                .header().add("typ", "JWT")
-                .and()
-                .issuedAt(Date.from(now.atZone(ZoneId.systemDefault()).toInstant()))
-                .notBefore(Date.from(now.atZone(ZoneId.systemDefault()).toInstant()))
-                .expiration(Date.from(now.plus(expireAfter).atZone(ZoneId.systemDefault()).toInstant()))
-                .subject(subject)
-                .issuer(this.issuer)
-                .audience().add(audience)
-                .and()
-                .id(jtiCreator.nextId().toString());
-
-        if (claims != null && !claims.isEmpty()) {
-            builder.claims(claims);
-        }
-
-        return builder.signWith(key, algorithm)
-                .compact();
-    }
-
-    /**
-     * The ID creator for creating unique JWT IDs.
-     */
-    private final GuidCreator<?> jtiCreator;
-
-    /**
-     * The algorithm to sign this token.
-     */
-    private final SecureDigestAlgorithm<SecretKey, SecretKey> algorithm;
-
-    /**
-     * The issuer of this token.
-     */
-    private final String issuer;
-
-    /**
-     * The signature key of this token.
-     */
-    private final SecretKey key;
-
-    /**
-     * The config of this token resolver.
-     */
-    private final JjwtTokenResolverConfig config = JjwtTokenResolverConfig.getInstance();
-}
diff --git a/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/config/JjwtTokenResolverConfig.java b/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/config/JjwtTokenResolverConfig.java
deleted file mode 100644
index db955be..0000000
--- a/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/config/JjwtTokenResolverConfig.java
+++ /dev/null
@@ -1,121 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.onixbyte.simplejwt.jjwt.config;
-
-import com.onixbyte.simplejwt.TokenResolver;
-import com.onixbyte.simplejwt.config.TokenResolverConfig;
-import com.onixbyte.simplejwt.constants.TokenAlgorithm;
-import com.onixbyte.simplejwt.exceptions.UnsupportedAlgorithmException;
-import com.onixbyte.simplejwt.jjwt.JjwtTokenResolver;
-import io.jsonwebtoken.Jwts;
-import io.jsonwebtoken.security.SecureDigestAlgorithm;
-
-import javax.crypto.SecretKey;
-import java.util.HashMap;
-import java.util.Map;
-
-/**
- * The {@code JjwtTokenResolverConfig} class provides the configuration for
- * the {@link JjwtTokenResolver}.
- * <p>
- * This configuration is used to establish the mapping between the standard
- * {@link TokenAlgorithm} defined in the
- * {@code cn.org.codecrafters:simple-jwt-facade} and the specific algorithms
- * used by the {@code io.jsonwebtoken:jjwt} library, which is the underlying
- * library used by {@link JjwtTokenResolver} to handle JSON Web Tokens
- * (JWTs).
- * <p>
- * <b>Algorithm Mapping:</b>
- * The {@code JjwtTokenResolverConfig} allows specifying the relationships
- * between the standard {@link TokenAlgorithm} instances supported by
- * {@link JjwtTokenResolver} and the corresponding algorithms used by the
- * {@code io.jsonwebtoken:jjwt} library. The mapping is achieved using a Map,
- * where the keys are the standard {@link TokenAlgorithm} instances, and the
- * values represent the algorithm functions used by
- * {@code io.jsonwebtoken:jjwt} library for each corresponding key.
- * <p>
- * <b>Note:</b>
- * The provided algorithm mapping should be consistent with the actual
- * algorithms supported and used by the {@code io.jsonwebtoken:jjwt} library.
- * It is crucial to ensure that the mapping is accurate to enable proper token
- * validation and processing within the {@link JjwtTokenResolver}.
- *
- * @author Zihlu Wang
- * @version 1.1.1
- * @since 1.0.0
- */
-public final class JjwtTokenResolverConfig implements TokenResolverConfig<SecureDigestAlgorithm<SecretKey, SecretKey>> {
-
-    /**
-     * Get the instance for io.jsonwebtoken:jjwt config.
-     * @return the instance for io.jsonwebtoken:jjwt config
-     */
-    public static JjwtTokenResolverConfig getInstance() {
-        if (instance == null) {
-            instance = new JjwtTokenResolverConfig();
-        }
-
-        return instance;
-    }
-
-    /**
-     * Gets the algorithm function corresponding to the specified
-     * {@link TokenAlgorithm}.
-     * <p>
-     * This method returns the algorithm function associated with the given
-     * {@link TokenAlgorithm}. The provided {@link TokenAlgorithm} represents
-     * the specific algorithm for which the corresponding algorithm function is
-     * required. The returned algorithm function represents the function
-     * implementation that can be used by the {@link TokenResolver} to handle
-     * the specific algorithm.
-     *
-     * @param algorithm the {@link TokenAlgorithm} for which the algorithm
-     *                  function is required
-     * @return the algorithm function associated with the given {@link
-     * TokenAlgorithm}
-     */
-    @Override
-    public SecureDigestAlgorithm<SecretKey, SecretKey> getAlgorithm(TokenAlgorithm algorithm) {
-        if (!SUPPORTED_ALGORITHMS.containsKey(algorithm)) {
-            throw new UnsupportedAlgorithmException("""
-                    The request algorithm is not supported by our system yet. Please change to supported ones.""");
-        }
-        return SUPPORTED_ALGORITHMS.get(algorithm);
-    }
-
-    /**
-     * Private constructor will protect this class from being instantiated.
-     */
-    private JjwtTokenResolverConfig() {
-    }
-
-    /**
-     * A {@code Map} to map a {@link TokenAlgorithm} to {@link SecureDigestAlgorithm}.
-     */
-    private static final Map<TokenAlgorithm, SecureDigestAlgorithm<SecretKey, SecretKey>> SUPPORTED_ALGORITHMS = new HashMap<>() {{
-        put(TokenAlgorithm.HS256, Jwts.SIG.HS256);
-        put(TokenAlgorithm.HS384, Jwts.SIG.HS384);
-        put(TokenAlgorithm.HS512, Jwts.SIG.HS512);
-    }};
-
-    /**
-     * The instance of this config class.
-     */
-    private static JjwtTokenResolverConfig instance;
-
-}
diff --git a/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/config/package-info.java b/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/config/package-info.java
deleted file mode 100644
index e94187a..0000000
--- a/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/config/package-info.java
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * The package {@code cn.org.codecrafters.simplejwt.jjwt.config} contains
- * configuration classes related to the {@link
- * com.onixbyte.simplejwt.jjwt.JjwtTokenResolver}
- * implementation.
- * <p>
- * The classes in this package provide configuration options and settings for
- * the {@link com.onixbyte.simplejwt.jjwt.JjwtTokenResolver},
- * which is used for resolving JSON Web Tokens (JWT) using the Auth0 library.
- * <p>
- * The {@link
- * com.onixbyte.simplejwt.jjwt.config.JjwtTokenResolverConfig}
- * class is a configuration class that defines the mapping between standard
- * {@link com.onixbyte.simplejwt.constants.TokenAlgorithm} and the
- * corresponding function implementation used by {@link
- * com.onixbyte.simplejwt.jjwt.JjwtTokenResolver} for handling
- * JWT algorithms. It enables developers to specify and customize the
- * algorithm functions according to the chosen JWT algorithm and the library
- * being used.
- * <p>
- * The configuration options in this package help developers integrate and
- * configure the {@link
- * com.onixbyte.simplejwt.jjwt.JjwtTokenResolver} seamlessly
- * into their Spring Boot applications. Developers can fine-tune the token
- * resolution process and customize algorithm handling to align with their
- * specific requirements and desired level of security.
- * <p>
- * It is recommended to explore the classes in this package to understand how
- * to configure and use the {@link
- * com.onixbyte.simplejwt.jjwt.JjwtTokenResolver} effectively
- * in the Spring Boot environment to handle JWT authentication and
- * authorisation securely and efficiently.
- *
- * @since 1.0.0
- */
-package com.onixbyte.simplejwt.jjwt.config;
\ No newline at end of file
diff --git a/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/package-info.java b/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/package-info.java
deleted file mode 100644
index 23be51d..0000000
--- a/simple-jwt-jjwt/src/main/java/com/onixbyte/simplejwt/jjwt/package-info.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * This package contains classes related to the integration of the {@code
- * io.jsonwebtoken:jjwt-api} library in the Simple JWT project. {@code
- * io.jsonwebtoken:jjwt-api} is a powerful and widely-used Identity as a Service
- * (IDaaS) platform that provides secure authentication and authorisation
- * solutions for web and mobile applications. The classes in this package
- * provide the necessary functionality to handle JSON Web Tokens (JWTs) using
- * the {@code io.jsonwebtoken:jjwt-api} library.
- * <p>
- * The main class in this package is the {@link
- * com.onixbyte.simplejwt.jjwt.JjwtTokenResolver}, which
- * implements the {@link com.onixbyte.simplejwt.TokenResolver} interface
- * and uses the {@code io.jsonwebtoken:jjwt-api} library to handle JWT
- * operations. It provides the functionality to create, validate, and extract
- * JWTs using the {@code io.jsonwebtoken:jjwt-api} library. Developers can use
- * this class as the main token resolver in the Simple JWT project when
- * integrating {@code io.jsonwebtoken:jjwt-api} as the JWT management library.
- * <p>
- * The {@link com.onixbyte.simplejwt.jjwt.JjwtTokenResolver} relies on
- * the {@code io.jsonwebtoken:jjwt-api}
- * library to handle the underlying JWT operations, including token creation,
- * validation, and extraction. It utilizes the {@code io.jsonwebtoken:jjwt-api}
- * {@link io.jsonwebtoken.SignatureAlgorithm} class to define and use different
- * algorithms for JWT signing and verification.
- * <p>
- * To use the {@link com.onixbyte.simplejwt.jjwt.JjwtTokenResolver},
- * developers must provide the necessary configurations and dependencies, such
- * as the {@link com.onixbyte.guid.GuidCreator} for generating unique
- * JWT IDs (JTI), the supported algorithm function, the issuer name, and the
- * secret key used for token signing and validation. The
- * {@link com.onixbyte.simplejwt.jjwt.config.JjwtTokenResolverConfig}
- * class provides a convenient way to configure these dependencies.
- * <p>
- * Developers using the {@code io.jsonwebtoken:jjwt-api} integration should be
- * familiar with the concepts and usage of the {@code io.jsonwebtoken:jjwt-api}
- * library and follow the official {@code io.jsonwebtoken:jjwt-api}
- * documentation for best practices and security considerations.
- *
- * @since 1.0.0
- */
-package com.onixbyte.simplejwt.jjwt;
\ No newline at end of file
diff --git a/simple-jwt-spring-boot-starter/build.gradle.kts b/simple-jwt-spring-boot-starter/build.gradle.kts
index b267e79..3464e97 100644
--- a/simple-jwt-spring-boot-starter/build.gradle.kts
+++ b/simple-jwt-spring-boot-starter/build.gradle.kts
@@ -25,7 +25,7 @@ val licenseName: String by project
 val licenseUrl: String by project
 
 val javaJwtVersion: String by project
-val jjwtVersion: String by project
+val jacksonVersion: String by project
 val springBootVersion: String by project
 
 group = buildGroupId
@@ -36,10 +36,7 @@ dependencies {
     implementation(project(":simple-jwt-facade"))
     compileOnly("com.auth0:java-jwt:$javaJwtVersion")
     compileOnly(project(":simple-jwt-authzero"))
-    compileOnly("io.jsonwebtoken:jjwt-api:$jjwtVersion")
-    compileOnly("io.jsonwebtoken:jjwt-impl:$jjwtVersion")
-    compileOnly("io.jsonwebtoken:jjwt-jackson:$jjwtVersion")
-    compileOnly(project(":simple-jwt-jjwt"))
+    implementation("com.fasterxml.jackson.core:jackson-databind:$jacksonVersion")
     implementation("org.springframework.boot:spring-boot-autoconfigure:$springBootVersion")
     implementation("org.springframework.boot:spring-boot-starter-logging:$springBootVersion")
     implementation("org.springframework.boot:spring-boot-configuration-processor:$springBootVersion")
diff --git a/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/AuthzeroTokenResolverAutoConfiguration.java b/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/AuthzeroTokenResolverAutoConfiguration.java
index 03dad48..e3b26ec 100644
--- a/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/AuthzeroTokenResolverAutoConfiguration.java
+++ b/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/AuthzeroTokenResolverAutoConfiguration.java
@@ -23,6 +23,7 @@
 import com.onixbyte.simplejwt.autoconfiguration.properties.SimpleJwtProperties;
 import com.auth0.jwt.interfaces.DecodedJWT;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.onixbyte.simplejwt.constants.TokenAlgorithm;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
@@ -35,25 +36,23 @@
 import org.springframework.context.annotation.Bean;
 
 /**
- * {@code AuthzeroTokenResolverAutoConfiguration} is responsible for
- * automatically configuring the Simple JWT library with
- * {@code com.auth0:java-jwt} when used in a Spring Boot application. It
- * provides default settings and configurations to ensure that the library
- * works smoothly without requiring manual configuration.
+ * {@code AuthzeroTokenResolverAutoConfiguration} is responsible for automatically configuring the
+ * Simple JWT library with
+ * {@code com.auth0:java-jwt} when used in a Spring Boot application. It provides default settings
+ * and configurations to ensure that the library works smoothly without requiring
+ * manual configuration.
  * <p>
- * This autoconfiguration class sets up the necessary beans and components
- * required for JWT generation and validation. It automatically creates and
- * configures the {@link AuthzeroTokenResolver} bean based on the available
- * options and properties.
+ * This autoconfiguration class sets up the necessary beans and components required for JWT
+ * generation and validation. It automatically creates and configures the
+ * {@link AuthzeroTokenResolver} bean based on the available options and properties.
  * <p>
- * Developers using the Simple JWT library with Spring Boot do not need to
- * explicitly configure the library, as the autoconfiguration takes care of
- * setting up the necessary components and configurations automatically.
- * However, developers still have the flexibility to customise the behavior of
- * the library by providing their own configurations and properties.
+ * Developers using the Simple JWT library with Spring Boot do not need to explicitly configure the
+ * library, as the autoconfiguration takes care of setting up the necessary components and
+ * configurations automatically. However, developers still have the flexibility to customise the
+ * behavior of the library by providing their own configurations and properties.
  *
- * @author Zihlu Wang
- * @version 1.0.0
+ * @author zihluwang
+ * @version 1.6.0
  * @since 1.0.0
  */
 @Slf4j
@@ -70,11 +69,13 @@ public class AuthzeroTokenResolverAutoConfiguration {
      * provided SimpleJwtProperties.
      *
      * @param simpleJwtProperties a {@link SimpleJwtProperties} instance
-     * @param jtiCreator a creator to create ids for JSON Web Token
-     * @param objectMapper jackson JSON Handler
+     * @param jtiCreator          a creator to create ids for JSON Web Token
+     * @param objectMapper        jackson JSON Handler
      */
     @Autowired
-    public AuthzeroTokenResolverAutoConfiguration(SimpleJwtProperties simpleJwtProperties, @Qualifier("jtiCreator") GuidCreator<?> jtiCreator, ObjectMapper objectMapper) {
+    public AuthzeroTokenResolverAutoConfiguration(SimpleJwtProperties simpleJwtProperties,
+                                                  @Qualifier("jtiCreator") GuidCreator<?> jtiCreator,
+                                                  ObjectMapper objectMapper) {
         this.jtiCreator = jtiCreator;
         this.simpleJwtProperties = simpleJwtProperties;
         this.objectMapper = objectMapper;
@@ -90,13 +91,21 @@ public AuthzeroTokenResolverAutoConfiguration(SimpleJwtProperties simpleJwtPrope
      */
     @Bean
     public TokenResolver<DecodedJWT> tokenResolver() {
-        return new AuthzeroTokenResolver(
-                jtiCreator,
-                simpleJwtProperties.algorithm(),
-                simpleJwtProperties.issuer(),
-                simpleJwtProperties.secret(),
-                objectMapper
-        );
+        var builder = AuthzeroTokenResolver.builder();
+
+        if (TokenAlgorithm.HMAC_ALGORITHMS.contains(simpleJwtProperties.getAlgorithm())) {
+            builder.keyPair(simpleJwtProperties.getPublicKey(), simpleJwtProperties.getPrivateKey())
+                    .algorithm(simpleJwtProperties.getAlgorithm());
+        } else if (TokenAlgorithm.ECDSA_ALGORITHMS.contains(simpleJwtProperties.getAlgorithm())) {
+            builder.secret(simpleJwtProperties.getSecret())
+                    .algorithm(simpleJwtProperties.getAlgorithm());
+        }
+
+        builder.issuer(simpleJwtProperties.getIssuer());
+        builder.jtiCreator(jtiCreator);
+        builder.objectMapper(objectMapper);
+
+        return builder.build();
     }
 
     private final GuidCreator<?> jtiCreator;
diff --git a/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/JjwtTokenResolverAutoConfiguration.java b/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/JjwtTokenResolverAutoConfiguration.java
deleted file mode 100644
index 37f2d54..0000000
--- a/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/JjwtTokenResolverAutoConfiguration.java
+++ /dev/null
@@ -1,110 +0,0 @@
-/*
- * Copyright (C) 2024-2024 OnixByte.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.onixbyte.simplejwt.autoconfiguration;
-
-import com.onixbyte.guid.GuidCreator;
-import com.onixbyte.simplejwt.TokenResolver;
-import com.onixbyte.simplejwt.autoconfiguration.properties.SimpleJwtProperties;
-import com.onixbyte.simplejwt.jjwt.JjwtTokenResolver;
-import io.jsonwebtoken.Claims;
-import io.jsonwebtoken.Jws;
-import lombok.extern.slf4j.Slf4j;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.annotation.Qualifier;
-import org.springframework.boot.autoconfigure.AutoConfiguration;
-import org.springframework.boot.autoconfigure.AutoConfigureAfter;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
-import org.springframework.boot.context.properties.EnableConfigurationProperties;
-import org.springframework.context.annotation.Bean;
-
-/**
- * {@code JjwtTokenResolverAutoConfiguration} is responsible for automatically
- * configuring the Simple JWT library with {@code io.jsonwebtoken:jjwt-api}
- * when used in a Spring Boot application. It provides default settings and
- * configurations to ensure that the library works smoothly without requiring
- * manual configuration.
- * <p>
- * This autoconfiguration class sets up the necessary beans and components
- * required for JWT generation and validation. It automatically creates and
- * configures the {@link JjwtTokenResolver} bean based on the available options
- * and properties.
- * <p>
- * Developers using the Simple JWT library with Spring Boot do not need to
- * explicitly configure the library, as the autoconfiguration takes care of
- * setting up the necessary components and configurations automatically.
- * However, developers still have the flexibility to customize the behavior of
- * the library by providing their own configurations and properties.
- *
- * @author Zihlu Wang
- * @version 1.1.0
- * @since 1.0.0
- */
-@Slf4j
-@AutoConfiguration
-@EnableConfigurationProperties(value = {SimpleJwtProperties.class})
-@ConditionalOnClass({Jws.class, Claims.class, JjwtTokenResolver.class})
-@ConditionalOnMissingBean({TokenResolver.class})
-@ConditionalOnBean(value = {GuidCreator.class}, name = "jtiCreator")
-@AutoConfigureAfter(value = GuidAutoConfiguration.class)
-public class JjwtTokenResolverAutoConfiguration {
-
-    /**
-     * Constructs a new {@code SimpleJwtAutoConfiguration} instance with the provided
-     * {@link SimpleJwtProperties}.
-     *
-     * @param jtiCreator          a creator to create JSON Web Token ids
-     * @param simpleJwtProperties the SimpleJwtProperties instance
-     */
-    @Autowired
-    public JjwtTokenResolverAutoConfiguration(SimpleJwtProperties simpleJwtProperties, @Qualifier("jtiCreator") GuidCreator<?> jtiCreator) {
-        this.jtiCreator = jtiCreator;
-        this.simpleJwtProperties = simpleJwtProperties;
-    }
-
-    /**
-     * Creates a new {@link TokenResolver} bean using {@link JjwtTokenResolver} if no existing
-     * {@link TokenResolver} bean is found. The {@link JjwtTokenResolver} is configured with the
-     * provided {@link GuidCreator}, {@code algorithm}, {@code issuer}, and {@code secret}
-     * properties from {@link SimpleJwtProperties}.
-     *
-     * @return the {@link TokenResolver} instance
-     */
-    @Bean
-    public TokenResolver<Jws<Claims>> tokenResolver() {
-        return new JjwtTokenResolver(
-                jtiCreator,
-                simpleJwtProperties.algorithm(),
-                simpleJwtProperties.issuer(),
-                simpleJwtProperties.secret()
-        );
-    }
-
-    /**
-     * The GuidCreator instance to be used for generating JWT IDs (JTI).
-     */
-    private final GuidCreator<?> jtiCreator;
-
-    /**
-     * The {@code SimpleJwtProperties} instance containing the configuration properties
-     * for Simple JWT.
-     */
-    private final SimpleJwtProperties simpleJwtProperties;
-
-}
diff --git a/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/properties/SimpleJwtProperties.java b/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/properties/SimpleJwtProperties.java
index 47d121e..fb92243 100644
--- a/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/properties/SimpleJwtProperties.java
+++ b/simple-jwt-spring-boot-starter/src/main/java/com/onixbyte/simplejwt/autoconfiguration/properties/SimpleJwtProperties.java
@@ -20,7 +20,6 @@
 import com.onixbyte.simplejwt.SecretCreator;
 import com.onixbyte.simplejwt.autoconfiguration.AuthzeroTokenResolverAutoConfiguration;
 import com.onixbyte.simplejwt.constants.TokenAlgorithm;
-import com.onixbyte.simplejwt.jjwt.JjwtTokenResolver;
 import lombok.Data;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 
@@ -31,9 +30,8 @@
  * "onixbyte.simple-jwt".
  * <p>
  * {@code SimpleJwtProperties} provides configuration options for the JWT algorithm, issuer,
- * and secret. The properties are used by the {@link AuthzeroTokenResolverAutoConfiguration} and
- * {@link JjwtTokenResolver} to set up the necessary configurations for JWT generation
- * and validation.
+ * and secret. The properties are used by the {@link AuthzeroTokenResolverAutoConfiguration} to
+ * set up the necessary configurations for JWT generation and validation.
  * <p>
  * Developers can customise the JWT algorithm, issuer, and secret by setting the corresponding
  * properties in the application's properties file. The {@code SimpleJwtAutoConfiguration} class
@@ -72,31 +70,14 @@ public SimpleJwtProperties() {
     private String secret = SecretCreator.createSecret(32, true, true, true);
 
     /**
-     * Returns the JWT algorithm configured in the properties.
-     *
-     * @return the JWT algorithm
+     * The private key, PEM formatted.
      */
-    public final TokenAlgorithm algorithm() {
-        return algorithm;
-    }
-
-    /**
-     * Returns the issuer value configured in the properties.
-     *
-     * @return the issuer value
-     */
-    public final String issuer() {
-        return issuer;
-    }
+    private String privateKey;
 
     /**
-     * Returns the secret key configured in the properties.
-     *
-     * @return the secret key
+     * The public key, PEM formatted
      */
-    public final String secret() {
-        return secret;
-    }
+    private String publicKey;
 
 }