com.nimbusds.jose.crypto.impl.AESKW Maven / Gradle / Ivy
Show all versions of nimbus-jose-jwt Show documentation
/*
* nimbus-jose-jwt
*
* Copyright 2012-2016, Connect2id Ltd and contributors.
*
* 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.nimbusds.jose.crypto.impl;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.Provider;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import com.nimbusds.jose.JOSEException;
import com.nimbusds.jose.util.KeyUtils;
import net.jcip.annotations.ThreadSafe;
/**
* AES key Wrapping methods for Content Encryption Key (CEK) encryption and
* decryption. This class is thread-safe.
*
* See RFC 7518 (JWA), section 4.4.
*
* @author Melisa Halsband
* @author Vladimir Dzhuvinov
* @version 2018-03-09
*/
@ThreadSafe
public class AESKW {
/**
* Wraps the specified Content Encryption Key (CEK).
*
* @param cek The Content Encryption Key (CEK) to wrap. Must not
* be {@code null}.
* @param kek The AES Key Encryption Key (KEK) (wrapping key).
* Must not be {@code null}.
* @param provider The specific JCA provider to use, {@code null}
* implies the default system one.
*
* @return The wrapped Content Encryption Key (CEK).
*
* @throws JOSEException If wrapping failed.
*/
public static byte[] wrapCEK(final SecretKey cek,
final SecretKey kek,
final Provider provider)
throws JOSEException {
try {
Cipher cipher;
if (provider != null) {
cipher = Cipher.getInstance("AESWrap", provider);
} else {
cipher = Cipher.getInstance("AESWrap");
}
cipher.init(Cipher.WRAP_MODE, kek);
return cipher.wrap(cek);
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException e) {
throw new JOSEException("Couldn't wrap AES key: " + e.getMessage(), e);
}
}
/**
* Unwraps the specified encrypted Content Encryption Key (CEK).
*
* @param kek The AES Key Encryption Key (KEK) (wrapping key).
* Must not be {@code null}.
* @param encryptedCEK The wrapped Content Encryption Key (CEK) with
* authentication tag. Must not be {@code null}.
* @param provider The specific JCA provider to use, {@code null}
* implies the default system one.
*
* @return The unwrapped Content Encryption Key (CEK).
*
* @throws JOSEException If unwrapping failed.
*/
public static SecretKey unwrapCEK(final SecretKey kek,
final byte[] encryptedCEK,
final Provider provider)
throws JOSEException {
try {
Cipher cipher;
if (provider != null) {
cipher = Cipher.getInstance("AESWrap", provider);
} else {
cipher = Cipher.getInstance("AESWrap");
}
cipher.init(Cipher.UNWRAP_MODE, KeyUtils.toAESKey(kek)); // Make sure key alg is "AES"
return (SecretKey)cipher.unwrap(encryptedCEK, "AES", Cipher.SECRET_KEY);
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException e) {
throw new JOSEException("Couldn't unwrap AES key: " + e.getMessage(), e);
}
}
/**
* Prevents public instantiation.
*/
private AESKW() {
}
}