Merge pull request #16 from MarkoKosmajac/java-aes-encryption-decryption

AES java algorithm

Author: jvm-coder

AESEncryptionDecryption.java

@@ -0,0 +1,81 @@
+import java.io.UnsupportedEncodingException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+import java.util.Base64;
+ 
+import javax.crypto.Cipher;
+import javax.crypto.spec.SecretKeySpec;
+ 
+public class AES {
+ 
+    private static SecretKeySpec secretKey;
+    private static byte[] key;
+ 
+    public static void setKey(String myKey) 
+    {
+        MessageDigest sha = null;
+        try {
+            key = myKey.getBytes("UTF-8");
+            sha = MessageDigest.getInstance("SHA-1");
+            key = sha.digest(key);
+            key = Arrays.copyOf(key, 16); 
+            secretKey = new SecretKeySpec(key, "AES");
+        } 
+        catch (NoSuchAlgorithmException e) {
+            e.printStackTrace();
+        } 
+        catch (UnsupportedEncodingException e) {
+            e.printStackTrace();
+        }
+    }
+ 
+    public static String encrypt(String strToEncrypt, String secret) 
+    {
+        try
+        {
+            setKey(secret);
+            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
+            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
+            return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes("UTF-8")));
+        } 
+        catch (Exception e) 
+        {
+            System.out.println("Found error while encrypting: " + e.toString());
+        }
+        return null;
+    }
+ 
+    public static String decrypt(String strToDecrypt, String secret) 
+    {
+        try
+        {
+            setKey(secret);
+            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
+            cipher.init(Cipher.DECRYPT_MODE, secretKey);
+            return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
+        } 
+        catch (Exception e) 
+        {
+            System.out.println("Found error while decrypting: " + e.toString());
+        }
+        return null;
+    }
+}
+
+/*  TESTCODE TO RUN:
+
+public static void main(String[] args) 
+{
+    final String secretKey = "donttellanyone!";
+     
+    String originalString = "THISISASTRING";
+    String encryptedString = AES.encrypt(originalString, secretKey) ;
+    String decryptedString = AES.decrypt(encryptedString, secretKey) ;
+     
+    System.out.println(originalString);
+    System.out.println(encryptedString);
+    System.out.println(decryptedString);
+}
+
+*/