Override hashCode in AttestationApplicationId.

+ some nits:
- add explicit encoding,
- reorder comparison to have the constant on RHS,
- rename private method in RootOfTrust as the previous name did not
desribe its operation,
- fix typo in an enum,
- make inner class ByteArrayComparator static.

Change-Id: Ib8999627907310492496e1b7fd08ed27d7b6b16f

server/src/main/java/com/google/android/attestation/AttestationApplicationId.java

@@ -19,10 +19,13 @@
 import static com.google.android.attestation.Constants.ATTESTATION_APPLICATION_ID_SIGNATURE_DIGESTS_INDEX;
 import static com.google.android.attestation.Constants.ATTESTATION_PACKAGE_INFO_PACKAGE_NAME_INDEX;
 import static com.google.android.attestation.Constants.ATTESTATION_PACKAGE_INFO_VERSION_INDEX;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
 import org.bouncycastle.asn1.ASN1Encodable;
 import org.bouncycastle.asn1.ASN1Integer;
 import org.bouncycastle.asn1.ASN1OctetString;
@@ -111,6 +114,11 @@ public boolean equals(Object o) {
         && (compareTo((AttestationApplicationId) o) == 0);
   }
 
+  @Override
+  public int hashCode() {
+    return Objects.hash(packageInfos, Arrays.deepHashCode(signatureDigests.toArray()));
+  }
+
   /** Provides package's name and version number. */
   public static class AttestationPackageInfo implements Comparable<AttestationPackageInfo> {
     public final String packageName;
@@ -121,7 +129,8 @@ private AttestationPackageInfo(ASN1Sequence packageInfo) {
           new String(
               ((ASN1OctetString)
                       packageInfo.getObjectAt(ATTESTATION_PACKAGE_INFO_PACKAGE_NAME_INDEX))
-                  .getOctets());
+                  .getOctets(),
+              UTF_8);
       this.version =
           ((ASN1Integer) packageInfo.getObjectAt(ATTESTATION_PACKAGE_INFO_VERSION_INDEX))
               .getValue()
@@ -148,11 +157,16 @@ public int compareTo(AttestationPackageInfo other) {
 
     @Override
     public boolean equals(Object o) {
-      return (o instanceof AttestationPackageInfo) && (0 == compareTo((AttestationPackageInfo) o));
+      return (o instanceof AttestationPackageInfo) && (compareTo((AttestationPackageInfo) o) == 0);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(packageName, version);
     }
   }
 
-  private class ByteArrayComparator implements java.util.Comparator<byte[]> {
+  private static class ByteArrayComparator implements java.util.Comparator<byte[]> {
     @Override
     public int compare(byte[] a, byte[] b) {
       int res = Integer.compare(a.length, b.length);

server/src/main/java/com/google/android/attestation/RootOfTrust.java

@@ -42,7 +42,7 @@ private RootOfTrust(ASN1Sequence rootOfTrust, int attestationVersion) {
     this.deviceLocked =
         ASN1Parsing.getBooleanFromAsn1(rootOfTrust.getObjectAt(ROOT_OF_TRUST_DEVICE_LOCKED_INDEX));
     this.verifiedBootState =
-        rootOfTrustToEnum(
+        verifiedBootStateToEnum(
             ASN1Parsing.getIntegerFromAsn1(
                 rootOfTrust.getObjectAt(ROOT_OF_TRUST_VERIFIED_BOOT_STATE_INDEX)));
     if (attestationVersion >= 3) {
@@ -61,12 +61,12 @@ static RootOfTrust createRootOfTrust(ASN1Sequence rootOfTrust, int attestationVe
     return new RootOfTrust(rootOfTrust, attestationVersion);
   }
 
-  private static VerifiedBootState rootOfTrustToEnum(int securityLevel) {
+  private static VerifiedBootState verifiedBootStateToEnum(int securityLevel) {
     switch (securityLevel) {
       case KM_VERIFIED_BOOT_STATE_VERIFIED:
         return VerifiedBootState.VERIFIED;
       case KM_VERIFIED_BOOT_STATE_SELF_SIGNED:
-        return VerifiedBootState.SELFSIGNED;
+        return VerifiedBootState.SELF_SIGNED;
       case KM_VERIFIED_BOOT_STATE_UNVERIFIED:
         return VerifiedBootState.UNVERIFIED;
       case KM_VERIFIED_BOOT_STATE_FAILED:
@@ -82,7 +82,7 @@ private static VerifiedBootState rootOfTrustToEnum(int securityLevel) {
    */
   public enum VerifiedBootState {
     VERIFIED,
-    SELFSIGNED,
+    SELF_SIGNED,
     UNVERIFIED,
     FAILED
   }

server/src/test/java/com/google/android/attestation/AttestationApplicationIdTest.java

@@ -31,16 +31,17 @@
 public class AttestationApplicationIdTest {
 
   // Generated from certificate with RSA Algorithm and StrongBox Security Level
-  private static final String ATTESTATION_APPLICATION_ID =
-      "MIIBszGCAYswDAQHYW5kcm9pZAIBHTAZBBRjb20uYW5kcm9pZC5rZXljaGFpbgIBHTAZBBRjb20uYW5kcm9pZC5zZXR0"
-          + "aW5ncwIBHTAZBBRjb20ucXRpLmRpYWdzZXJ2aWNlcwIBHTAaBBVjb20uYW5kcm9pZC5keW5zeXN0ZW0CAR0wHQ"
-          + "QYY29tLmFuZHJvaWQuaW5wdXRkZXZpY2VzAgEdMB8EGmNvbS5hbmRyb2lkLmxvY2FsdHJhbnNwb3J0AgEdMB8E"
-          + "GmNvbS5hbmRyb2lkLmxvY2F0aW9uLmZ1c2VkAgEdMB8EGmNvbS5hbmRyb2lkLnNlcnZlci50ZWxlY29tAgEdMC"
-          + "AEG2NvbS5hbmRyb2lkLndhbGxwYXBlcmJhY2t1cAIBHTAhBBxjb20uZ29vZ2xlLlNTUmVzdGFydERldGVjdG9y"
-          + "AgEdMCIEHWNvbS5nb29nbGUuYW5kcm9pZC5oaWRkZW5tZW51AgEBMCMEHmNvbS5hbmRyb2lkLnByb3ZpZGVycy"
-          + "5zZXR0aW5ncwIBHTEiBCAwGqPLCBE0UBxF8UIqvGbCQiT9Xe1f3I8X5pcXb9hmqg==";
-  private static final DEROctetString ATTESTATION_APPLICATION_ID_OCTETS =
-      new DEROctetString(Base64.decode(ATTESTATION_APPLICATION_ID));
+  private static final DEROctetString ATTESTATION_APPLICATION_ID =
+      new DEROctetString(
+          Base64.decode(
+              "MIIBszGCAYswDAQHYW5kcm9pZAIBHTAZBBRjb20uYW5kcm9pZC5rZXljaGFpbgIBHTAZBBRjb20uYW5kcm9p"
+                  + "ZC5zZXR0aW5ncwIBHTAZBBRjb20ucXRpLmRpYWdzZXJ2aWNlcwIBHTAaBBVjb20uYW5kcm9pZC5keW"
+                  + "5zeXN0ZW0CAR0wHQQYY29tLmFuZHJvaWQuaW5wdXRkZXZpY2VzAgEdMB8EGmNvbS5hbmRyb2lkLmxv"
+                  + "Y2FsdHJhbnNwb3J0AgEdMB8EGmNvbS5hbmRyb2lkLmxvY2F0aW9uLmZ1c2VkAgEdMB8EGmNvbS5hbm"
+                  + "Ryb2lkLnNlcnZlci50ZWxlY29tAgEdMCAEG2NvbS5hbmRyb2lkLndhbGxwYXBlcmJhY2t1cAIBHTAh"
+                  + "BBxjb20uZ29vZ2xlLlNTUmVzdGFydERldGVjdG9yAgEdMCIEHWNvbS5nb29nbGUuYW5kcm9pZC5oaW"
+                  + "RkZW5tZW51AgEBMCMEHmNvbS5hbmRyb2lkLnByb3ZpZGVycy5zZXR0aW5ncwIBHTEiBCAwGqPLCBE0"
+                  + "UBxF8UIqvGbCQiT9Xe1f3I8X5pcXb9hmqg=="));
 
   private static final List<AttestationPackageInfo> EXPECTED_PACKAGE_INFOS =
       ImmutableList.of(
@@ -66,7 +67,7 @@ public class AttestationApplicationIdTest {
   @Test
   public void testCreateAttestationApplicationId() {
     AttestationApplicationId attestationApplicationId =
-        AttestationApplicationId.createAttestationApplicationId(ATTESTATION_APPLICATION_ID_OCTETS);
+        AttestationApplicationId.createAttestationApplicationId(ATTESTATION_APPLICATION_ID);
     assertThat(attestationApplicationId).isEqualTo(EXPECTED_ATTESTATION_APPLICATION_ID);
   }
 
@@ -75,7 +76,31 @@ public void testCreateEmptyAttestationApplicationIdFromEmptyOrInvalidInput() {
     assertThat(AttestationApplicationId.createAttestationApplicationId(null)).isNull();
     assertThat(
             AttestationApplicationId.createAttestationApplicationId(
-                new DEROctetString(Base64.decode("Invalid DEROcetet String"))))
+                new DEROctetString(Base64.decode("Invalid DEROctet String"))))
         .isNull();
   }
+
+  @Test
+  public void testEquals() {
+    AttestationApplicationId attestationApplicationId =
+        AttestationApplicationId.createAttestationApplicationId(ATTESTATION_APPLICATION_ID);
+    AttestationApplicationId emptyAttestationApplicationId =
+        new AttestationApplicationId(ImmutableList.of(), ImmutableList.of());
+
+    assertThat(attestationApplicationId.equals(EXPECTED_ATTESTATION_APPLICATION_ID)).isTrue();
+    assertThat(EXPECTED_ATTESTATION_APPLICATION_ID.equals(attestationApplicationId)).isTrue();
+
+    assertThat(attestationApplicationId.equals(emptyAttestationApplicationId)).isFalse();
+    assertThat(emptyAttestationApplicationId.equals(attestationApplicationId)).isFalse();
+  }
+
+  @Test
+  public void testEqualObjectsHaveEqualHashCodes() {
+    AttestationApplicationId attestationApplicationId =
+        AttestationApplicationId.createAttestationApplicationId(ATTESTATION_APPLICATION_ID);
+
+    assertThat(attestationApplicationId.equals(EXPECTED_ATTESTATION_APPLICATION_ID)).isTrue();
+    assertThat(attestationApplicationId.hashCode())
+        .isEqualTo(EXPECTED_ATTESTATION_APPLICATION_ID.hashCode());
+  }
 }