/*************************************************************************** The Disc Image Chef ---------------------------------------------------------------------------- Filename : CDChecksums.cs Version : 1.0 Author(s) : Natalia Portillo Component : Checksums. Revision : $Revision$ Last change by : $Author$ Date : $Date$ --[ Description ] ---------------------------------------------------------- Checks a CD checksum --[ License ] -------------------------------------------------------------- This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . ---------------------------------------------------------------------------- Copyright (C) 2011-2014 Claunia.com ECC algorithm from ECM (C) 2002-2011 Neill Corlett ****************************************************************************/ //$Id$ using System; using DiscImageChef.Console; namespace DiscImageChef.Checksums { public static class CDChecksums { static byte[] ECC_F_Table; static byte[] ECC_B_Table; const UInt32 CDCRC32Poly = 0xD8018001; const UInt32 CDCRC32Seed = 0x00000000; public static bool? CheckCDSector(byte[] buffer) { switch(buffer.Length) { case 2448: { byte[] subchannel = new byte[96]; byte[] channel = new byte[2352]; Array.Copy(buffer, 0, channel, 0, 2352); Array.Copy(buffer, 2352, subchannel, 0, 96); bool? channelStatus = CheckCDSectorChannel(channel); bool? subchannelStatus = CheckCDSectorSubChannel(subchannel); bool? status = null; if(channelStatus == null && subchannelStatus == null) status = null; if(channelStatus == false || subchannelStatus == false) status = false; if(channelStatus == null && subchannelStatus == true) status = true; if(channelStatus == true && subchannelStatus == null) status = true; if(channelStatus == true && subchannelStatus == true) status = true; return status; } case 2352: return CheckCDSectorChannel(buffer); default: return null; } } static void ECCInit() { ECC_F_Table = new byte[256]; ECC_B_Table = new byte[256]; for(UInt32 i = 0; i < 256; i++) { UInt32 j = (uint)((i << 1) ^ ((i & 0x80) == 0x80 ? 0x11D : 0)); ECC_F_Table[i] = (byte)j; ECC_B_Table[i ^ j] = (byte)i; } } static bool CheckECC( byte[] address, byte[] data, UInt32 major_count, UInt32 minor_count, UInt32 major_mult, UInt32 minor_inc, byte[] ecc ) { UInt32 size = major_count * minor_count; UInt32 major; for(major = 0; major < major_count; major++) { UInt32 index = (major >> 1) * major_mult + (major & 1); byte ecc_a = 0; byte ecc_b = 0; UInt32 minor; for(minor = 0; minor < minor_count; minor++) { byte temp; if(index < 4) { temp = address[index]; } else { temp = data[index - 4]; } index += minor_inc; if(index >= size) { index -= size; } ecc_a ^= temp; ecc_b ^= temp; ecc_a = ECC_F_Table[ecc_a]; } ecc_a = ECC_B_Table[ECC_F_Table[ecc_a] ^ ecc_b]; if( ecc[major] != (ecc_a) || ecc[major + major_count] != (ecc_a ^ ecc_b)) { return false; } } return true; } static bool? CheckCDSectorChannel(byte[] channel) { ECCInit(); if( channel[0x000] == 0x00 && // sync (12 bytes) channel[0x001] == 0xFF && channel[0x002] == 0xFF && channel[0x003] == 0xFF && channel[0x004] == 0xFF && channel[0x005] == 0xFF && channel[0x006] == 0xFF && channel[0x007] == 0xFF && channel[0x008] == 0xFF && channel[0x009] == 0xFF && channel[0x00A] == 0xFF && channel[0x00B] == 0x00) { DicConsole.DebugWriteLine("CD checksums", "Data sector, address {0:X2}:{1:X2}:{2:X2}", channel[0x00C], channel[0x00D], channel[0x00E]); if(channel[0x00F] == 0x00) // mode (1 byte) { DicConsole.DebugWriteLine("CD checksums", "Mode 0 sector at address {0:X2}:{1:X2}:{2:X2}", channel[0x00C], channel[0x00D], channel[0x00E]); for(int i = 0x010; i < 0x930; i++) { if(channel[i] != 0x00) { DicConsole.DebugWriteLine("CD checksums", "Mode 0 sector with error at address: {0:X2}:{1:X2}:{2:X2}", channel[0x00C], channel[0x00D], channel[0x00E]); return false; } } return true; } else if(channel[0x00F] == 0x01) // mode (1 byte) { DicConsole.DebugWriteLine("CD checksums", "Mode 1 sector at address {0:X2}:{1:X2}:{2:X2}", channel[0x00C], channel[0x00D], channel[0x00E]); if(channel[0x814] != 0x00 || // reserved (8 bytes) channel[0x815] != 0x00 || channel[0x816] != 0x00 || channel[0x817] != 0x00 || channel[0x818] != 0x00 || channel[0x819] != 0x00 || channel[0x81A] != 0x00 || channel[0x81B] != 0x00) { DicConsole.DebugWriteLine("CD checksums", "Mode 1 sector with data in reserved bytes at address: {0:X2}:{1:X2}:{2:X2}", channel[0x00C], channel[0x00D], channel[0x00E]); return false; } byte[] address = new byte[4]; byte[] data = new byte[2060]; byte[] data2 = new byte[2232]; byte[] ecc_p = new byte[172]; byte[] ecc_q = new byte[104]; Array.Copy(channel, 0x0C, address, 0, 4); Array.Copy(channel, 0x0C, data, 0, 2060); Array.Copy(channel, 0x0C, data2, 0, 2232); Array.Copy(channel, 0x81C, ecc_p, 0, 172); Array.Copy(channel, 0x8C8, ecc_q, 0, 104); bool FailedECC_P = CheckECC(address, data, 86, 24, 2, 86, ecc_p); bool FailedECC_Q = CheckECC(address, data2, 52, 43, 86, 88, ecc_q); if(FailedECC_P) DicConsole.DebugWriteLine("CD checksums", "Mode 1 sector at address: {0:X2}:{1:X2}:{2:X2}, fails ECC P check", channel[0x00C], channel[0x00D], channel[0x00E]); if(FailedECC_Q) DicConsole.DebugWriteLine("CD checksums", "Mode 1 sector at address: {0:X2}:{1:X2}:{2:X2}, fails ECC Q check", channel[0x00C], channel[0x00D], channel[0x00E]); if(FailedECC_P || FailedECC_Q) return false; byte[] SectorForCheck = new byte[0x810]; UInt32 StoredEDC = BitConverter.ToUInt32(channel, 0x810); byte[] CalculatedEDCBytes; Array.Copy(channel, 0, SectorForCheck, 0, 0x810); CRC32Context.Data(SectorForCheck, 0x810, out CalculatedEDCBytes, CDCRC32Poly, CDCRC32Seed); UInt32 CalculatedEDC = BitConverter.ToUInt32(CalculatedEDCBytes, 0); if(CalculatedEDC != StoredEDC) { DicConsole.DebugWriteLine("CD checksums", "Mode 1 sector at address: {0:X2}:{1:X2}:{2:X2}, got CRC 0x{3:X8} expected 0x{4:X8}", channel[0x00C], channel[0x00D], channel[0x00E], CalculatedEDC, StoredEDC); return false; } return true; } else if(channel[0x00F] == 0x02) // mode (1 byte) { DicConsole.DebugWriteLine("CD checksums", "Mode 2 sector at address {0:X2}:{1:X2}:{2:X2}", channel[0x00C], channel[0x00D], channel[0x00E]); if((channel[0x012] & 0x20) == 0x20) // mode 2 form 2 { if(channel[0x010] != channel[0x014] || channel[0x011] != channel[0x015] || channel[0x012] != channel[0x016] || channel[0x013] != channel[0x017]) { DicConsole.DebugWriteLine("CD checksums", "Subheader copies differ in mode 2 form 2 sector at address: {0:X2}:{1:X2}:{2:X2}", channel[0x00C], channel[0x00D], channel[0x00E]); } byte[] SectorForCheck = new byte[0x91C]; UInt32 StoredEDC = BitConverter.ToUInt32(channel, 0x92C); byte[] CalculatedEDCBytes; Array.Copy(channel, 0x10, SectorForCheck, 0, 0x91C); CRC32Context.Data(SectorForCheck, 0x91C, out CalculatedEDCBytes, CDCRC32Poly, CDCRC32Seed); UInt32 CalculatedEDC = BitConverter.ToUInt32(CalculatedEDCBytes, 0); if(CalculatedEDC != StoredEDC && StoredEDC != 0x00000000) { DicConsole.DebugWriteLine("CD checksums", "Mode 2 form 2 sector at address: {0:X2}:{1:X2}:{2:X2}, got CRC 0x{3:X8} expected 0x{4:X8}", channel[0x00C], channel[0x00D], channel[0x00E], CalculatedEDC, StoredEDC); return false; } } else { if(channel[0x010] != channel[0x014] || channel[0x011] != channel[0x015] || channel[0x012] != channel[0x016] || channel[0x013] != channel[0x017]) { DicConsole.DebugWriteLine("CD checksums", "Subheader copies differ in mode 2 form 1 sector at address: {0:X2}:{1:X2}:{2:X2}", channel[0x00C], channel[0x00D], channel[0x00E]); } byte[] address = new byte[4]; byte[] data = new byte[2060]; byte[] data2 = new byte[2232]; byte[] ecc_p = new byte[172]; byte[] ecc_q = new byte[104]; address[0] = 0; address[1] = 0; address[2] = 0; address[3] = 0; Array.Copy(channel, 0x0C, data, 0, 2060); Array.Copy(channel, 0x0C, data2, 0, 2232); Array.Copy(channel, 0x80C, ecc_p, 0, 172); Array.Copy(channel, 0x8B8, ecc_q, 0, 104); bool FailedECC_P = CheckECC(address, data, 86, 24, 2, 86, ecc_p); bool FailedECC_Q = CheckECC(address, data2, 52, 43, 86, 88, ecc_q); if(FailedECC_P) DicConsole.DebugWriteLine("CD checksums", "Mode 2 form 1 sector at address: {0:X2}:{1:X2}:{2:X2}, fails ECC P check", channel[0x00C], channel[0x00D], channel[0x00E]); if(FailedECC_Q) DicConsole.DebugWriteLine("CD checksums", "Mode 2 form 1 sector at address: {0:X2}:{1:X2}:{2:X2}, fails ECC Q check", channel[0x00F], channel[0x00C], channel[0x00D], channel[0x00E]); if(FailedECC_P || FailedECC_Q) return false; byte[] SectorForCheck = new byte[0x808]; UInt32 StoredEDC = BitConverter.ToUInt32(channel, 0x818); byte[] CalculatedEDCBytes; Array.Copy(channel, 0x10, SectorForCheck, 0, 0x808); CRC32Context.Data(SectorForCheck, 0x808, out CalculatedEDCBytes, CDCRC32Poly, CDCRC32Seed); UInt32 CalculatedEDC = BitConverter.ToUInt32(CalculatedEDCBytes, 0); if(CalculatedEDC != StoredEDC) { DicConsole.DebugWriteLine("CD checksums", "Mode 2 form 1 sector at address: {0:X2}:{1:X2}:{2:X2}, got CRC 0x{3:X8} expected 0x{4:X8}", channel[0x00C], channel[0x00D], channel[0x00E], CalculatedEDC, StoredEDC); return false; } } return true; } else { DicConsole.DebugWriteLine("CD checksums", "Unknown mode {0} sector at address: {1:X2}:{2:X2}:{3:X2}", channel[0x00F], channel[0x00C], channel[0x00D], channel[0x00E]); return null; } } return null; } static bool? CheckCDSectorSubChannel(byte[] subchannel) { bool? status = true; byte[] QSubChannel = new byte[12]; byte[] CDTextPack1 = new byte[18]; byte[] CDTextPack2 = new byte[18]; byte[] CDTextPack3 = new byte[18]; byte[] CDTextPack4 = new byte[18]; byte[] CDSubRWPack1 = new byte[24]; byte[] CDSubRWPack2 = new byte[24]; byte[] CDSubRWPack3 = new byte[24]; byte[] CDSubRWPack4 = new byte[24]; int i = 0; for(int j = 0; j < 12; j++) QSubChannel[j] = 0; for(int j = 0; j < 18; j++) { CDTextPack1[j] = 0; CDTextPack2[j] = 0; CDTextPack3[j] = 0; CDTextPack4[j] = 0; } for(int j = 0; j < 24; j++) { CDSubRWPack1[j] = 0; CDSubRWPack2[j] = 0; CDSubRWPack3[j] = 0; CDSubRWPack4[j] = 0; } for(int j = 0; j < 12; j++) { QSubChannel[j] = (byte)(QSubChannel[j] | ((subchannel[i++] & 0x40) << 1)); QSubChannel[j] = (byte)(QSubChannel[j] | (subchannel[i++] & 0x40)); QSubChannel[j] = (byte)(QSubChannel[j] | ((subchannel[i++] & 0x40) >> 1)); QSubChannel[j] = (byte)(QSubChannel[j] | ((subchannel[i++] & 0x40) >> 2)); QSubChannel[j] = (byte)(QSubChannel[j] | ((subchannel[i++] & 0x40) >> 3)); QSubChannel[j] = (byte)(QSubChannel[j] | ((subchannel[i++] & 0x40) >> 4)); QSubChannel[j] = (byte)(QSubChannel[j] | ((subchannel[i++] & 0x40) >> 5)); QSubChannel[j] = (byte)(QSubChannel[j] | ((subchannel[i++] & 0x40) >> 6)); } i = 0; for(int j = 0; j < 18; j++) { if(j < 18) CDTextPack1[j] = (byte)(CDTextPack1[j] | ((subchannel[i++] & 0x3F) << 2)); if(j < 18) CDTextPack1[j] = (byte)(CDTextPack1[j++] | ((subchannel[i] & 0xC0) >> 4)); if(j < 18) CDTextPack1[j] = (byte)(CDTextPack1[j] | ((subchannel[i++] & 0x0F) << 4)); if(j < 18) CDTextPack1[j] = (byte)(CDTextPack1[j++] | ((subchannel[i] & 0x3C) >> 2)); if(j < 18) CDTextPack1[j] = (byte)(CDTextPack1[j] | ((subchannel[i++] & 0x03) << 6)); if(j < 18) CDTextPack1[j] = (byte)(CDTextPack1[j] | (subchannel[i++] & 0x3F)); } for(int j = 0; j < 18; j++) { if(j < 18) CDTextPack2[j] = (byte)(CDTextPack2[j] | ((subchannel[i++] & 0x3F) << 2)); if(j < 18) CDTextPack2[j] = (byte)(CDTextPack2[j++] | ((subchannel[i] & 0xC0) >> 4)); if(j < 18) CDTextPack2[j] = (byte)(CDTextPack2[j] | ((subchannel[i++] & 0x0F) << 4)); if(j < 18) CDTextPack2[j] = (byte)(CDTextPack2[j++] | ((subchannel[i] & 0x3C) >> 2)); if(j < 18) CDTextPack2[j] = (byte)(CDTextPack2[j] | ((subchannel[i++] & 0x03) << 6)); if(j < 18) CDTextPack2[j] = (byte)(CDTextPack2[j] | (subchannel[i++] & 0x3F)); } for(int j = 0; j < 18; j++) { if(j < 18) CDTextPack3[j] = (byte)(CDTextPack3[j] | ((subchannel[i++] & 0x3F) << 2)); if(j < 18) CDTextPack3[j] = (byte)(CDTextPack3[j++] | ((subchannel[i] & 0xC0) >> 4)); if(j < 18) CDTextPack3[j] = (byte)(CDTextPack3[j] | ((subchannel[i++] & 0x0F) << 4)); if(j < 18) CDTextPack3[j] = (byte)(CDTextPack3[j++] | ((subchannel[i] & 0x3C) >> 2)); if(j < 18) CDTextPack3[j] = (byte)(CDTextPack3[j] | ((subchannel[i++] & 0x03) << 6)); if(j < 18) CDTextPack3[j] = (byte)(CDTextPack3[j] | (subchannel[i++] & 0x3F)); } for(int j = 0; j < 18; j++) { if(j < 18) CDTextPack4[j] = (byte)(CDTextPack4[j] | ((subchannel[i++] & 0x3F) << 2)); if(j < 18) CDTextPack4[j] = (byte)(CDTextPack4[j++] | ((subchannel[i] & 0xC0) >> 4)); if(j < 18) CDTextPack4[j] = (byte)(CDTextPack4[j] | ((subchannel[i++] & 0x0F) << 4)); if(j < 18) CDTextPack4[j] = (byte)(CDTextPack4[j++] | ((subchannel[i] & 0x3C) >> 2)); if(j < 18) CDTextPack4[j] = (byte)(CDTextPack4[j] | ((subchannel[i++] & 0x03) << 6)); if(j < 18) CDTextPack4[j] = (byte)(CDTextPack4[j] | (subchannel[i++] & 0x3F)); } i = 0; for(int j = 0; j < 24; j++) { CDSubRWPack1[j] = (byte)(subchannel[i++] & 0x3F); } for(int j = 0; j < 24; j++) { CDSubRWPack2[j] = (byte)(subchannel[i++] & 0x3F); } for(int j = 0; j < 24; j++) { CDSubRWPack3[j] = (byte)(subchannel[i++] & 0x3F); } for(int j = 0; j < 24; j++) { CDSubRWPack4[j] = (byte)(subchannel[i++] & 0x3F); } switch(CDSubRWPack1[0]) { case 0x00: DicConsole.DebugWriteLine("CD checksums", "Detected Zero Pack in subchannel"); break; case 0x08: DicConsole.DebugWriteLine("CD checksums", "Detected Line Graphics Pack in subchannel"); break; case 0x09: DicConsole.DebugWriteLine("CD checksums", "Detected CD+G Pack in subchannel"); break; case 0x0A: DicConsole.DebugWriteLine("CD checksums", "Detected CD+EG Pack in subchannel"); break; case 0x14: DicConsole.DebugWriteLine("CD checksums", "Detected CD-TEXT Pack in subchannel"); break; case 0x18: DicConsole.DebugWriteLine("CD checksums", "Detected CD+MIDI Pack in subchannel"); break; case 0x38: DicConsole.DebugWriteLine("CD checksums", "Detected User Pack in subchannel"); break; default: DicConsole.DebugWriteLine("CD checksums", "Detected unknown Pack type in subchannel: mode {0}, item {1}", Convert.ToString(CDSubRWPack1[0] & 0x38, 2), Convert.ToString(CDSubRWPack1[0] & 0x07, 2)); break; } BigEndianBitConverter.IsLittleEndian = true; UInt16 QSubChannelCRC = BigEndianBitConverter.ToUInt16(QSubChannel, 10); byte[] QSubChannelForCRC = new byte[10]; Array.Copy(QSubChannel, 0, QSubChannelForCRC, 0, 10); UInt16 CalculatedQCRC = CalculateCCITT_CRC16(QSubChannelForCRC); if(QSubChannelCRC != CalculatedQCRC) { DicConsole.DebugWriteLine("CD checksums", "Q subchannel CRC 0x{0:X4}, expected 0x{1:X4}", CalculatedQCRC, QSubChannelCRC); status = false; } if((CDTextPack1[0] & 0x80) == 0x80) { UInt16 CDTextPack1CRC = BigEndianBitConverter.ToUInt16(CDTextPack1, 16); byte[] CDTextPack1ForCRC = new byte[16]; Array.Copy(CDTextPack1, 0, CDTextPack1ForCRC, 0, 16); UInt16 CalculatedCDTP1CRC = CalculateCCITT_CRC16(CDTextPack1ForCRC); if(CDTextPack1CRC != CalculatedCDTP1CRC && CDTextPack1CRC != 0) { DicConsole.DebugWriteLine("CD checksums", "CD-Text Pack 1 CRC 0x{0:X4}, expected 0x{1:X4}", CDTextPack1CRC, CalculatedCDTP1CRC); status = false; } } if((CDTextPack2[0] & 0x80) == 0x80) { UInt16 CDTextPack2CRC = BigEndianBitConverter.ToUInt16(CDTextPack2, 16); byte[] CDTextPack2ForCRC = new byte[16]; Array.Copy(CDTextPack2, 0, CDTextPack2ForCRC, 0, 16); UInt16 CalculatedCDTP2CRC = CalculateCCITT_CRC16(CDTextPack2ForCRC); DicConsole.DebugWriteLine("CD checksums", "Cyclic CDTP2 0x{0:X4}, Calc CDTP2 0x{1:X4}", CDTextPack2CRC, CalculatedCDTP2CRC); if(CDTextPack2CRC != CalculatedCDTP2CRC && CDTextPack2CRC != 0) { DicConsole.DebugWriteLine("CD checksums", "CD-Text Pack 2 CRC 0x{0:X4}, expected 0x{1:X4}", CDTextPack2CRC, CalculatedCDTP2CRC); status = false; } } if((CDTextPack3[0] & 0x80) == 0x80) { UInt16 CDTextPack3CRC = BigEndianBitConverter.ToUInt16(CDTextPack3, 16); byte[] CDTextPack3ForCRC = new byte[16]; Array.Copy(CDTextPack3, 0, CDTextPack3ForCRC, 0, 16); UInt16 CalculatedCDTP3CRC = CalculateCCITT_CRC16(CDTextPack3ForCRC); DicConsole.DebugWriteLine("CD checksums", "Cyclic CDTP3 0x{0:X4}, Calc CDTP3 0x{1:X4}", CDTextPack3CRC, CalculatedCDTP3CRC); if(CDTextPack3CRC != CalculatedCDTP3CRC && CDTextPack3CRC != 0) { DicConsole.DebugWriteLine("CD checksums", "CD-Text Pack 3 CRC 0x{0:X4}, expected 0x{1:X4}", CDTextPack3CRC, CalculatedCDTP3CRC); status = false; } } if((CDTextPack4[0] & 0x80) == 0x80) { UInt16 CDTextPack4CRC = BigEndianBitConverter.ToUInt16(CDTextPack4, 16); byte[] CDTextPack4ForCRC = new byte[16]; Array.Copy(CDTextPack4, 0, CDTextPack4ForCRC, 0, 16); UInt16 CalculatedCDTP4CRC = CalculateCCITT_CRC16(CDTextPack4ForCRC); DicConsole.DebugWriteLine("CD checksums", "Cyclic CDTP4 0x{0:X4}, Calc CDTP4 0x{1:X4}", CDTextPack4CRC, CalculatedCDTP4CRC); if(CDTextPack4CRC != CalculatedCDTP4CRC && CDTextPack4CRC != 0) { DicConsole.DebugWriteLine("CD checksums", "CD-Text Pack 4 CRC 0x{0:X4}, expected 0x{1:X4}", CDTextPack4CRC, CalculatedCDTP4CRC); status = false; } } return status; } static readonly ushort[] CCITT_CRC16Table = { 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0, }; static ushort CalculateCCITT_CRC16(byte[] buffer) { UInt16 CRC16 = 0; for(int i = 0; i < buffer.Length; i++) { CRC16 = (ushort)(CCITT_CRC16Table[(CRC16 >> 8) ^ buffer[i]] ^ (CRC16 << 8)); } CRC16 = (ushort)~CRC16; return CRC16; } } }