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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8 with debug enabled.
package org.bouncycastle.crypto.macs;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.Mac;
import org.bouncycastle.crypto.OutputLengthException;
import org.bouncycastle.crypto.digests.DSTU7564Digest;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.util.Pack;
/**
* Implementation of DSTU7564 MAC mode
*/
public class DSTU7564Mac
implements Mac
{
private static final int BITS_IN_BYTE = 8;
private DSTU7564Digest engine;
private int macSize;
private byte[] paddedKey;
private byte[] invertedKey;
private long inputLength;
public DSTU7564Mac(int macBitSize)
{
/* Mac size can be only 256 / 384 / 512. Same as hash size for DSTU7654Digest */
this.engine = new DSTU7564Digest(macBitSize);
this.macSize = macBitSize / BITS_IN_BYTE;
this.paddedKey = null;
this.invertedKey = null;
}
public void init(CipherParameters params)
throws IllegalArgumentException
{
if (params instanceof KeyParameter)
{
byte[] key = ((KeyParameter)params).getKey();
invertedKey = new byte[key.length];
paddedKey = padKey(key);
for (int byteIndex = 0; byteIndex < invertedKey.length; byteIndex++)
{
invertedKey[byteIndex] = (byte)(key[byteIndex] ^ (byte)0xFF);
}
}
else
{
throw new IllegalArgumentException("Bad parameter passed");
}
engine.update(paddedKey, 0, paddedKey.length);
}
public String getAlgorithmName()
{
return "DSTU7564Mac";
}
public int getMacSize()
{
return macSize;
}
public void update(byte in)
throws IllegalStateException
{
engine.update(in);
inputLength++;
}
public void update(byte[] in, int inOff, int len)
throws DataLengthException, IllegalStateException
{
if (in.length - inOff < len)
{
throw new DataLengthException("Input buffer too short");
}
if (paddedKey == null)
{
throw new IllegalStateException(getAlgorithmName() + " not initialised");
}
engine.update(in, inOff, len);
inputLength += len;
}
public int doFinal(byte[] out, int outOff)
throws DataLengthException, IllegalStateException
{
if (paddedKey == null)
{
throw new IllegalStateException(getAlgorithmName() + " not initialised");
}
if (out.length - outOff < macSize)
{
throw new OutputLengthException("Output buffer too short");
}
pad();
engine.update(invertedKey, 0, invertedKey.length);
inputLength = 0;
return engine.doFinal(out, outOff);
}
public void reset()
{
inputLength = 0;
engine.reset();
if (paddedKey != null)
{
engine.update(paddedKey, 0, paddedKey.length);
}
}
private void pad()
{
int extra = engine.getByteLength() - (int)(inputLength % engine.getByteLength());
if (extra < 13) // terminator byte + 96 bits of length
{
extra += engine.getByteLength();
}
byte[] padded = new byte[extra];
padded[0] = (byte)0x80; // Defined in standard;
// Defined in standard;
Pack.longToLittleEndian(inputLength * BITS_IN_BYTE, padded, padded.length - 12);
engine.update(padded, 0, padded.length);
}
private byte[] padKey(byte[] in)
{
int paddedLen = ((in.length + engine.getByteLength() - 1) / engine.getByteLength()) * engine.getByteLength();
int extra = engine.getByteLength() - (int)(in.length % engine.getByteLength());
if (extra < 13) // terminator byte + 96 bits of length
{
paddedLen += engine.getByteLength();
}
byte[] padded = new byte[paddedLen];
System.arraycopy(in, 0, padded, 0, in.length);
padded[in.length] = (byte)0x80; // Defined in standard;
Pack.intToLittleEndian(in.length * BITS_IN_BYTE, padded, padded.length - 12); // Defined in standard;
return padded;
}
}
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