org.bouncycastle.crypto.macs.DSTU7564Mac Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of bcprov-ext-debug-jdk18on Show documentation
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 Java 1.8 and later with debug enabled.
The newest version!
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
    {
        paddedKey = null;
        reset();

        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;

        int res = engine.doFinal(out, outOff);

        reset();
        
        return res;
    }

    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 = paddedLen - in.length;
        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;
    }
}