AesBytesEncryptor constructor that uses secret key

Fixes: gh-8402

Author: eleftherias

crypto/src/main/java/org/springframework/security/crypto/encrypt/AesBytesEncryptor.java

@@ -36,7 +36,7 @@
 import org.springframework.security.crypto.keygen.KeyGenerators;
 
 /**
- * Encryptor that uses 256-bit AES encryption.
+ * Encryptor that uses AES encryption.
  *
  * @author Keith Donald
  * @author Dave Syer
@@ -99,9 +99,19 @@ public AesBytesEncryptor(String password, CharSequence salt,
 
 	public AesBytesEncryptor(String password, CharSequence salt,
 			BytesKeyGenerator ivGenerator, CipherAlgorithm alg) {
-		PBEKeySpec keySpec = new PBEKeySpec(password.toCharArray(), Hex.decode(salt),
-				1024, 256);
-		SecretKey secretKey = newSecretKey("PBKDF2WithHmacSHA1", keySpec);
+		this(newSecretKey("PBKDF2WithHmacSHA1", new PBEKeySpec(password.toCharArray(), Hex.decode(salt),
+				1024, 256)), ivGenerator, alg);
+	}
+
+	/**
+	 * Constructs an encryptor that uses AES encryption.
+	 *
+	 * @param secretKey the secret (symmetric) key
+	 * @param ivGenerator the generator used to generate the initialization vector. If null,
+	 * then a default algorithm will be used based on the provided {@link CipherAlgorithm}
+	 * @param alg the {@link CipherAlgorithm} to be used
+	 */
+	public AesBytesEncryptor(SecretKey secretKey, BytesKeyGenerator ivGenerator, CipherAlgorithm alg) {
 		this.secretKey = new SecretKeySpec(secretKey.getEncoded(), "AES");
 		this.alg = alg;
 		this.encryptor = alg.createCipher();

crypto/src/test/java/org/springframework/security/crypto/encrypt/AesBytesEncryptorTests.java

@@ -22,10 +22,15 @@
 import org.springframework.security.crypto.codec.Hex;
 import org.springframework.security.crypto.keygen.BytesKeyGenerator;
 
+import javax.crypto.SecretKey;
+import javax.crypto.spec.PBEKeySpec;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 import static org.springframework.security.crypto.encrypt.AesBytesEncryptor.CipherAlgorithm.GCM;
+import static org.springframework.security.crypto.encrypt.CipherUtils.newSecretKey;
+import static org.springframework.security.crypto.password.Pbkdf2PasswordEncoder.SecretKeyFactoryAlgorithm.PBKDF2WithHmacSHA1;
 
 /**
  * Tests for {@link AesBytesEncryptor}
@@ -69,6 +74,23 @@ public void roundtripWhenUsingDefaultCipherThenEncryptsAndDecrypts() {
 	public void roundtripWhenUsingGcmThenEncryptsAndDecrypts() {
 		CryptoAssumptions.assumeGCMJCE();
 		AesBytesEncryptor encryptor = new AesBytesEncryptor(this.password, this.hexSalt, this.generator, GCM);
+
+		byte[] encryption = encryptor.encrypt(this.secret.getBytes());
+		assertThat(new String(Hex.encode(encryption)))
+				.isEqualTo("4b0febebd439db7ca77153cb254520c3e4d61ae38207b4e42b820d311dc3d4e0e2f37ed5ee");
+
+		byte[] decryption = encryptor.decrypt(encryption);
+		assertThat(new String(decryption)).isEqualTo(this.secret);
+	}
+
+	@Test
+	public void roundtripWhenUsingSecretKeyThenEncryptsAndDecrypts() {
+		CryptoAssumptions.assumeGCMJCE();
+		PBEKeySpec keySpec = new PBEKeySpec(this.password.toCharArray(), Hex.decode(this.hexSalt),
+				1024, 256);
+		SecretKey secretKey = newSecretKey(PBKDF2WithHmacSHA1.name(), keySpec);
+		AesBytesEncryptor encryptor = new AesBytesEncryptor(secretKey, this.generator, GCM);
+
 		byte[] encryption = encryptor.encrypt(this.secret.getBytes());
 		assertThat(new String(Hex.encode(encryption)))
 				.isEqualTo("4b0febebd439db7ca77153cb254520c3e4d61ae38207b4e42b820d311dc3d4e0e2f37ed5ee");