org.apache.sshd.common.cipher.BaseGCMCipher Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.sshd.common.cipher;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.sshd.common.util.buffer.BufferUtils;
import org.apache.sshd.common.util.security.SecurityUtils;
public class BaseGCMCipher extends BaseCipher {
protected Mode mode;
protected boolean initialized;
protected CounterGCMParameterSpec parameters;
protected SecretKey secretKey;
public BaseGCMCipher(int ivsize, int authSize, int kdfSize, String algorithm, int keySize, String transformation,
int blkSize) {
super(ivsize, authSize, kdfSize, algorithm, keySize, transformation, blkSize);
}
@Override
protected Cipher createCipherInstance(Mode mode, byte[] key, byte[] iv) throws Exception {
this.mode = mode;
secretKey = new SecretKeySpec(key, getAlgorithm());
parameters = new CounterGCMParameterSpec(getAuthenticationTagSize() * Byte.SIZE, iv);
return SecurityUtils.getCipher(getTransformation());
}
protected Cipher getInitializedCipherInstance() throws Exception {
Cipher cipher = getCipherInstance();
if (!initialized) {
cipher.init(mode == Mode.Encrypt ? Cipher.ENCRYPT_MODE : Cipher.DECRYPT_MODE, secretKey, parameters);
initialized = true;
}
return cipher;
}
@Override
public void updateAAD(byte[] data, int offset, int length) throws Exception {
getInitializedCipherInstance().updateAAD(data, offset, length);
}
@Override
public void update(byte[] input, int inputOffset, int inputLen) throws Exception {
if (mode == Mode.Decrypt) {
inputLen += getAuthenticationTagSize();
}
Cipher cipher = getInitializedCipherInstance();
cipher.doFinal(input, inputOffset, inputLen, input, inputOffset);
parameters.incrementCounter();
initialized = false;
}
/**
* Algorithm parameters for AES/GCM that assumes the IV uses an 8-byte counter field as its least significant bytes.
*/
protected static class CounterGCMParameterSpec extends GCMParameterSpec {
protected final byte[] iv;
protected final long initialCounter;
protected CounterGCMParameterSpec(int tLen, byte[] src) {
super(tLen, src);
if (src.length != 12) {
throw new IllegalArgumentException("GCM nonce must be 12 bytes, but given len=" + src.length);
}
iv = src.clone();
initialCounter = BufferUtils.getLong(iv, iv.length - Long.BYTES, Long.BYTES);
}
protected void incrementCounter() {
int off = iv.length - Long.BYTES;
long counter = BufferUtils.getLong(iv, off, Long.BYTES);
long newCounter = counter + 1L;
if (newCounter == initialCounter) {
throw new IllegalStateException("GCM IV would be reused");
}
BufferUtils.putLong(newCounter, iv, off, Long.BYTES);
}
@Override
public byte[] getIV() {
// JCE implementation of GCM will complain if the reference doesn't change between inits
return iv.clone();
}
}
}