119 lines
2.7 KiB
C#
119 lines
2.7 KiB
C#
using System;
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namespace Org.BouncyCastle.Crypto.Digests
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{
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/**
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* base implementation of MD4 family style digest as outlined in
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* "Handbook of Applied Cryptography", pages 344 - 347.
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*/
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public abstract class GeneralDigest
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: IDigest
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{
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private const int BYTE_LENGTH = 64;
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private byte[] xBuf;
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private int xBufOff;
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private long byteCount;
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internal GeneralDigest()
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{
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xBuf = new byte[4];
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}
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internal GeneralDigest(GeneralDigest t)
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{
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xBuf = new byte[t.xBuf.Length];
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Array.Copy(t.xBuf, 0, xBuf, 0, t.xBuf.Length);
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xBufOff = t.xBufOff;
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byteCount = t.byteCount;
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}
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public void Update(byte input)
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{
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xBuf[xBufOff++] = input;
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if (xBufOff == xBuf.Length)
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{
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ProcessWord(xBuf, 0);
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xBufOff = 0;
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}
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byteCount++;
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}
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public void BlockUpdate(
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byte[] input,
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int inOff,
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int length)
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{
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//
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// fill the current word
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//
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while ((xBufOff != 0) && (length > 0))
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{
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Update(input[inOff]);
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inOff++;
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length--;
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}
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//
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// process whole words.
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//
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while (length > xBuf.Length)
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{
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ProcessWord(input, inOff);
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inOff += xBuf.Length;
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length -= xBuf.Length;
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byteCount += xBuf.Length;
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}
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//
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// load in the remainder.
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//
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while (length > 0)
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{
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Update(input[inOff]);
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inOff++;
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length--;
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}
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}
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public void Finish()
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{
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long bitLength = (byteCount << 3);
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//
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// add the pad bytes.
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//
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Update((byte)128);
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while (xBufOff != 0) Update((byte)0);
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ProcessLength(bitLength);
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ProcessBlock();
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}
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public virtual void Reset()
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{
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byteCount = 0;
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xBufOff = 0;
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for ( int i = 0; i < xBuf.Length; i++ ) xBuf[i] = 0;
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}
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public int GetByteLength()
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{
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return BYTE_LENGTH;
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}
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internal abstract void ProcessWord(byte[] input, int inOff);
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internal abstract void ProcessLength(long bitLength);
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internal abstract void ProcessBlock();
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public abstract string AlgorithmName { get; }
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public abstract int GetDigestSize();
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public abstract int DoFinal(byte[] output, int outOff);
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}
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}
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