org.rapidoid.crypto.AESCypherTool Maven / Gradle / Ivy
package org.rapidoid.crypto;
/*
* #%L
* rapidoid-commons
* %%
* Copyright (C) 2014 - 2017 Nikolche Mihajlovski 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.
* #L%
*/
import org.rapidoid.RapidoidThing;
import org.rapidoid.annotation.Authors;
import org.rapidoid.annotation.Since;
import org.rapidoid.commons.Arr;
import org.rapidoid.log.Log;
import org.rapidoid.u.U;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
@Authors("Nikolche Mihajlovski")
@Since("5.3.0")
public class AESCypherTool extends RapidoidThing {
private static final String AES_MODE = "AES/CBC/PKCS5Padding";
static final int AES_KEY_LENGTH = calcAESKeyLength(); // bits
private static int calcAESKeyLength() {
int maxKeyLen;
try {
maxKeyLen = Cipher.getMaxAllowedKeyLength("AES");
} catch (NoSuchAlgorithmException e) {
throw U.rte(e);
}
return maxKeyLen > 256 ? 256 : 128;
}
public byte[] encrypt(byte[] input, CryptoKey key) throws Exception {
byte[] aesIV = Crypto.randomBytes(16);
byte[] encrypted = aes(input, key.encryptionKey, aesIV, Cipher.ENCRYPT_MODE);
byte[] hmacSalt = Crypto.randomBytes(20);
byte[] hmac = Crypto.hmac(Arr.merge(encrypted, aesIV), key.hmacKey, hmacSalt);
return Arr.merge(aesIV, encrypted, hmacSalt, hmac);
}
public byte[] decrypt(byte[] input, CryptoKey key) throws Exception {
U.must(input.length >= 68, "Not enough data to decrypt!");
byte[] aesIV = new byte[16];
byte[] encrypted = new byte[input.length - 16 - 20 - 32];
byte[] hmacSalt = new byte[20];
byte[] hmac = new byte[32];
Arr.split(input, aesIV, encrypted, hmacSalt, hmac);
if (Crypto.hmacMatches(hmac, Arr.merge(encrypted, aesIV), key.hmacKey, hmacSalt)) {
return aes(encrypted, key.encryptionKey, aesIV, Cipher.DECRYPT_MODE);
} else {
Log.debug("Cannot decrypt invalid data. Has the secret changed?");
return null;
}
}
private byte[] aes(byte[] data, byte[] key, byte[] iv, int mode) throws Exception {
Cipher cipher = Cipher.getInstance(AES_MODE);
cipher.init(mode, new SecretKeySpec(key, "AES"), new IvParameterSpec(iv));
return cipher.doFinal(data);
}
}