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package org.beykery.util.bip44;
/*
* Copyright 2013, 2014 Megion Research & Development GmbH
*
* 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.
*/
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class Hmac {
private static final String SHA256 = "SHA-256";
private static final String SHA512 = "SHA-512";
private static final int SHA256_BLOCK_SIZE = 64;
private static final int SHA512_BLOCK_SIZE = 128;
public static byte[] hmacSha256(byte[] key, byte[] message) {
MessageDigest digest;
try {
digest = MessageDigest.getInstance(SHA256);
} catch (NoSuchAlgorithmException e) {
// Only happens if the platform does not support SHA-256
throw new RuntimeException(e);
}
return hmac(digest, SHA256_BLOCK_SIZE, key, message);
}
public static byte[] hmacSha512(byte[] key, byte[] message) {
MessageDigest digest;
try {
digest = MessageDigest.getInstance(SHA512);
} catch (NoSuchAlgorithmException e) {
// Only happens if the platform does not support SHA-512
throw new RuntimeException(e);
}
return hmac(digest, SHA512_BLOCK_SIZE, key, message);
}
private static byte[] hmac(MessageDigest digest, int blockSize, byte[] key, byte[] message) {
// Ensure sufficient key length
if (key.length > blockSize) {
key = hash(digest, key);
}
if (key.length < blockSize) {
// Zero pad
byte[] temp = new byte[blockSize];
System.arraycopy(key, 0, temp, 0, key.length);
key = temp;
}
// Prepare o key pad
byte[] o_key_pad = new byte[blockSize];
for (int i = 0; i < blockSize; i++) {
o_key_pad[i] = (byte) (0x5c ^ key[i]);
}
// Prepare i key pad
byte[] i_key_pad = new byte[blockSize];
for (int i = 0; i < blockSize; i++) {
i_key_pad[i] = (byte) (0x36 ^ key[i]);
}
return hash(digest, o_key_pad, hash(digest, i_key_pad, message));
}
private static byte[] hash(MessageDigest digest, byte[] data) {
digest.reset();
digest.update(data, 0, data.length);
return digest.digest();
}
private static byte[] hash(MessageDigest digest, byte[] data1, byte[] data2) {
digest.reset();
digest.update(data1, 0, data1.length);
digest.update(data2, 0, data2.length);
return digest.digest();
}
}
