100 lines
3.2 KiB
C#
Executable File
100 lines
3.2 KiB
C#
Executable File
using System;
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using System.Collections.Generic;
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using System.Text;
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namespace Shadowsocks.Encryption
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{
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public class SodiumEncryptor
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: IVEncryptor, IDisposable
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{
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const int CIPHER_SALSA20 = 1;
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const int CIPHER_CHACHA20 = 2;
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const int SODIUM_BLOCK_SIZE = 64;
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protected int _encryptBytesRemaining;
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protected int _decryptBytesRemaining;
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protected ulong _encryptIC;
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protected ulong _decryptIC;
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protected byte[] _encryptBuf;
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protected byte[] _decryptBuf;
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public SodiumEncryptor(string method, string password)
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: base(method, password)
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{
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InitKey(method, password);
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_encryptBuf = new byte[MAX_INPUT_SIZE + SODIUM_BLOCK_SIZE];
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_decryptBuf = new byte[MAX_INPUT_SIZE + SODIUM_BLOCK_SIZE];
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}
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private static Dictionary<string, int[]> _ciphers = new Dictionary<string, int[]> {
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{"salsa20", new int[]{32, 8, CIPHER_SALSA20, PolarSSL.AES_CTX_SIZE}},
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{"chacha20", new int[]{32, 8, CIPHER_CHACHA20, PolarSSL.AES_CTX_SIZE}},
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};
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protected override Dictionary<string, int[]> getCiphers()
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{
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return _ciphers;
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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>(_ciphers.Keys);
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}
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protected override void cipherUpdate(bool isCipher, int length, byte[] buf, byte[] outbuf)
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{
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// TODO write a unidirection cipher so we don't have to if if if
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int bytesRemaining;
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ulong ic;
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byte[] sodiumBuf;
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byte[] iv;
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if (isCipher)
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{
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bytesRemaining = _encryptBytesRemaining;
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ic = _encryptIC;
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sodiumBuf = _encryptBuf;
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iv = _encryptIV;
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}
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else
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{
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bytesRemaining = _decryptBytesRemaining;
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ic = _decryptIC;
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sodiumBuf = _decryptBuf;
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iv = _decryptIV;
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}
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int padding = bytesRemaining;
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Buffer.BlockCopy(buf, 0, sodiumBuf, padding, length);
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switch (_cipher)
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{
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case CIPHER_SALSA20:
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Sodium.crypto_stream_salsa20_xor_ic(sodiumBuf, sodiumBuf, (ulong)(padding + length), iv, ic, _key);
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break;
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case CIPHER_CHACHA20:
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Sodium.crypto_stream_chacha20_xor_ic(sodiumBuf, sodiumBuf, (ulong)(padding + length), iv, ic, _key);
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break;
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}
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Buffer.BlockCopy(sodiumBuf, padding, outbuf, 0, length);
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padding += length;
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ic += (ulong)padding / SODIUM_BLOCK_SIZE;
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bytesRemaining = padding % SODIUM_BLOCK_SIZE;
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if (isCipher)
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{
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_encryptBytesRemaining = bytesRemaining;
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_encryptIC = ic;
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}
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else
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{
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_decryptBytesRemaining = bytesRemaining;
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_decryptIC = ic;
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}
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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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