109 lines
3.5 KiB
Java
109 lines
3.5 KiB
Java
/**
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*
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* Copyright 2017 Paul Schaub
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.jivesoftware.smackx.ciphers;
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import java.security.InvalidAlgorithmParameterException;
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import java.security.InvalidKeyException;
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import java.security.NoSuchAlgorithmException;
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import java.security.NoSuchProviderException;
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import java.security.SecureRandom;
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import javax.crypto.Cipher;
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import javax.crypto.KeyGenerator;
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import javax.crypto.NoSuchPaddingException;
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import javax.crypto.SecretKey;
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import javax.crypto.spec.IvParameterSpec;
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import javax.crypto.spec.SecretKeySpec;
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public abstract class AesGcmNoPadding {
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public static final String keyType = "AES";
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public static final String cipherMode = "AES/GCM/NoPadding";
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private final int length;
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protected final Cipher cipher;
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protected final byte[] key, iv, keyAndIv;
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public AesGcmNoPadding(int bits) throws NoSuchAlgorithmException, NoSuchProviderException,
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NoSuchPaddingException, InvalidAlgorithmParameterException, InvalidKeyException {
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this.length = bits;
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int bytes = bits / 8;
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KeyGenerator keyGenerator = KeyGenerator.getInstance(keyType);
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keyGenerator.init(bits);
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key = keyGenerator.generateKey().getEncoded();
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SecureRandom secureRandom = new SecureRandom();
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iv = new byte[bytes];
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secureRandom.nextBytes(iv);
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keyAndIv = new byte[2 * bytes];
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System.arraycopy(key, 0, keyAndIv, 0, bytes);
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System.arraycopy(iv, 0, keyAndIv, bytes, bytes);
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SecretKey secretKey = new SecretKeySpec(key, keyType);
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IvParameterSpec ivSpec = new IvParameterSpec(iv);
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cipher = Cipher.getInstance(cipherMode, "BC");
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cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivSpec);
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}
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public AesGcmNoPadding(byte[] key, byte[] iv) throws NoSuchPaddingException, NoSuchAlgorithmException,
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NoSuchProviderException, InvalidAlgorithmParameterException, InvalidKeyException {
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this.length = key.length;
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this.key = key;
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this.iv = iv;
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int bytes = length / 8;
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keyAndIv = new byte[2 * bytes];
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System.arraycopy(key, 0, keyAndIv, 0, bytes);
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System.arraycopy(iv, 0, keyAndIv, bytes, bytes);
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cipher = Cipher.getInstance(cipherMode, "BC");
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SecretKeySpec keySpec = new SecretKeySpec(key, keyType);
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IvParameterSpec ivSpec = new IvParameterSpec(iv);
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cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
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}
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public byte[] getKeyAndIv() {
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return keyAndIv.clone();
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}
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public byte[] getKey() {
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return key.clone();
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}
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public byte[] getIv() {
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return iv.clone();
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}
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public int getLength() {
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return length;
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}
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public Cipher getCipher() {
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return cipher;
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}
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public abstract String getNamespace();
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public static byte[] copyOfRange(byte[] source, int start, int end) {
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byte[] copy = new byte[end - start];
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System.arraycopy(source, start, copy, 0, end - start);
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return copy;
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}
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}
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