109 lines
3.3 KiB
C#
109 lines
3.3 KiB
C#
using System;
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using System.Collections.Generic;
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namespace Shadowsocks.Encryption
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{
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public class TableEncryptor
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: EncryptorBase
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{
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public TableEncryptor(string method, string password)
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: base(method, password)
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{
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byte[] hash = GetPasswordHash();
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// TODO endian
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ulong a = BitConverter.ToUInt64(hash, 0);
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for (int i = 0; i < 256; i++)
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{
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_encryptTable[i] = (byte)i;
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}
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for (int i = 1; i < 1024; i++)
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{
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_encryptTable = MergeSort(_encryptTable, a, i);
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}
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for (int i = 0; i < 256; i++)
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{
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_decryptTable[_encryptTable[i]] = (byte)i;
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}
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}
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public static List<string> SupportedCiphers()
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{
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return new List<string>(new string[]{"table"});
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}
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public override void Encrypt(byte[] buf, int length, byte[] outbuf, out int outlength)
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{
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byte[] result = new byte[length];
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for (int i = 0; i < length; i++)
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{
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outbuf[i] = _encryptTable[buf[i]];
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}
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outlength = length;
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}
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public override void Decrypt(byte[] buf, int length, byte[] outbuf, out int outlength)
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{
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byte[] result = new byte[length];
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for (int i = 0; i < length; i++)
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{
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outbuf[i] = _decryptTable[buf[i]];
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}
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outlength = length;
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}
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private readonly byte[] _encryptTable = new byte[256];
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private readonly byte[] _decryptTable = new byte[256];
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private static long Compare(byte x, byte y, ulong a, int i)
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{
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return (long)(a % (ulong)(x + i)) - (long)(a % (ulong)(y + i));
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}
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private byte[] MergeSort(byte[] array, ulong a, int j)
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{
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if (array.Length == 1)
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{
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return array;
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}
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int middle = array.Length / 2;
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byte[] left = new byte[middle];
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for (int i = 0; i < middle; i++)
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{
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left[i] = array[i];
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}
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byte[] right = new byte[array.Length - middle];
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for (int i = 0; i < array.Length - middle; i++)
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{
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right[i] = array[i + middle];
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}
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left = MergeSort(left, a, j);
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right = MergeSort(right, a, j);
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int leftptr = 0;
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int rightptr = 0;
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byte[] sorted = new byte[array.Length];
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for (int k = 0; k < array.Length; k++)
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{
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if (rightptr == right.Length || ((leftptr < left.Length) && (Compare(left[leftptr], right[rightptr], a, j) <= 0)))
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{
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sorted[k] = left[leftptr];
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leftptr++;
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}
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else if (leftptr == left.Length || ((rightptr < right.Length) && (Compare(right[rightptr], left[leftptr], a, j)) <= 0))
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{
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sorted[k] = right[rightptr];
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rightptr++;
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}
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}
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return sorted;
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}
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public override void Dispose()
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{
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}
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}
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}
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