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138 lines
4.3 KiB
138 lines
4.3 KiB
namespace com.hitrust.Security.Cryptography
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{
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using System;
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using System.Security.Cryptography;
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internal sealed class ARCFourManagedTransform : ICryptoTransform, IDisposable
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{
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private bool m_Disposed;
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private byte m_Index1;
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private byte m_Index2;
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private byte[] m_Key;
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private int m_KeyLen;
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private byte[] m_Permutation;
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public ARCFourManagedTransform(byte[] key)
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{
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this.m_Key = (byte[]) key.Clone();
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this.m_KeyLen = key.Length;
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this.m_Permutation = new byte[0x100];
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this.m_Disposed = false;
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this.Init();
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}
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public void Dispose()
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{
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Array.Clear(this.m_Key, 0, this.m_Key.Length);
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Array.Clear(this.m_Permutation, 0, this.m_Permutation.Length);
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this.m_Index1 = 0;
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this.m_Index2 = 0;
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this.m_Disposed = true;
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try
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{
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GC.SuppressFinalize(this);
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}
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catch
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{
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}
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}
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~ARCFourManagedTransform()
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{
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this.Dispose();
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}
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private void Init()
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{
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for (int i = 0; i < 0x100; i++)
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{
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this.m_Permutation[i] = (byte) i;
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}
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this.m_Index1 = 0;
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this.m_Index2 = 0;
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int index = 0;
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for (int j = 0; j < 0x100; j++)
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{
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index = ((index + this.m_Permutation[j]) + this.m_Key[j % this.m_KeyLen]) % 0x100;
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byte num = this.m_Permutation[j];
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this.m_Permutation[j] = this.m_Permutation[index];
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this.m_Permutation[index] = num;
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}
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}
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public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
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{
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if (this.m_Disposed)
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{
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throw new ObjectDisposedException(base.GetType().FullName);
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}
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if ((inputBuffer == null) || (outputBuffer == null))
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{
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throw new ArgumentNullException();
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}
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if (((inputOffset < 0) || (outputOffset < 0)) || (((inputOffset + inputCount) > inputBuffer.Length) || ((outputOffset + inputCount) > outputBuffer.Length)))
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{
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throw new ArgumentOutOfRangeException();
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}
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int num3 = inputOffset + inputCount;
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while (inputOffset < num3)
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{
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this.m_Index1 = (byte) ((this.m_Index1 + 1) % 0x100);
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this.m_Index2 = (byte) ((this.m_Index2 + this.m_Permutation[this.m_Index1]) % 0x100);
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byte num2 = this.m_Permutation[this.m_Index1];
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this.m_Permutation[this.m_Index1] = this.m_Permutation[this.m_Index2];
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this.m_Permutation[this.m_Index2] = num2;
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byte index = (byte) ((this.m_Permutation[this.m_Index1] + this.m_Permutation[this.m_Index2]) % 0x100);
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outputBuffer[outputOffset] = (byte) (inputBuffer[inputOffset] ^ this.m_Permutation[index]);
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inputOffset++;
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outputOffset++;
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}
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return inputCount;
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}
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public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
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{
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if (this.m_Disposed)
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{
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throw new ObjectDisposedException(base.GetType().FullName);
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}
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byte[] outputBuffer = new byte[inputCount];
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this.TransformBlock(inputBuffer, inputOffset, inputCount, outputBuffer, 0);
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this.Init();
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return outputBuffer;
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}
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public bool CanReuseTransform
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{
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get
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{
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return true;
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}
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}
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public bool CanTransformMultipleBlocks
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{
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get
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{
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return true;
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}
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}
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public int InputBlockSize
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{
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get
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{
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return 1;
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}
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}
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public int OutputBlockSize
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{
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get
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{
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return 1;
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}
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}
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}
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}
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