org.bouncycastle.crypto.digests.SHA3Digest Maven / Gradle / Ivy
package org.bouncycastle.crypto.digests;
/**
* implementation of SHA-3 based on following KeccakNISTInterface.c from http://keccak.noekeon.org/
*
* Following the naming conventions used in the C source code to enable easy review of the implementation.
*/
public class SHA3Digest
extends KeccakDigest
{
private static int checkBitLength(int bitLength)
{
switch (bitLength)
{
case 224:
case 256:
case 384:
case 512:
return bitLength;
default:
throw new IllegalArgumentException("'bitLength' " + bitLength + " not supported for SHA-3");
}
}
public SHA3Digest()
{
this(256);
}
public SHA3Digest(int bitLength)
{
super(checkBitLength(bitLength));
}
public SHA3Digest(SHA3Digest source) {
super(source);
}
public String getAlgorithmName()
{
return "SHA3-" + fixedOutputLength;
}
public int doFinal(byte[] out, int outOff)
{
absorbBits(0x02, 2);
return super.doFinal(out, outOff);
}
/*
* TODO Possible API change to support partial-byte suffixes.
*/
protected int doFinal(byte[] out, int outOff, byte partialByte, int partialBits)
{
if (partialBits < 0 || partialBits > 7)
{
throw new IllegalArgumentException("'partialBits' must be in the range [0,7]");
}
int finalInput = (partialByte & ((1 << partialBits) - 1)) | (0x02 << partialBits);
int finalBits = partialBits + 2;
if (finalBits >= 8)
{
absorb((byte)finalInput);
finalBits -= 8;
finalInput >>>= 8;
}
return super.doFinal(out, outOff, (byte)finalInput, finalBits);
}
}