proxmark3/common/iso14443crc.c
iceman1001 7838f4beba MERGED: @holimans changes
MERGED: @piwi changes
MERGED: @marshmellows changes.

I'm not even gonna try write up all that stuff..

ADD: changed some commands inside the "Hf 14a sim" on deviceside.
ADD: @mobeius "two nonce" version for mfkey32.   It is also inside the "hf 14a sim" with the "x" parameter.
2015-07-22 23:00:52 +02:00

48 lines
1.6 KiB
C

//-----------------------------------------------------------------------------
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// ISO14443 CRC calculation code.
//-----------------------------------------------------------------------------
#include "iso14443crc.h"
static unsigned short UpdateCrc14443(unsigned char ch, unsigned short *lpwCrc)
{
ch = (ch ^ (unsigned char) ((*lpwCrc) & 0x00FF));
ch = (ch ^ (ch << 4));
*lpwCrc = (*lpwCrc >> 8) ^ ((unsigned short) ch << 8) ^
((unsigned short) ch << 3) ^ ((unsigned short) ch >> 4);
return (*lpwCrc);
}
void ComputeCrc14443(int CrcType,
const unsigned char *Data, int Length,
unsigned char *TransmitFirst,
unsigned char *TransmitSecond)
{
unsigned char chBlock;
unsigned short wCrc=CrcType;
do {
chBlock = *Data++;
UpdateCrc14443(chBlock, &wCrc);
} while (--Length);
if (CrcType == CRC_14443_B)
wCrc = ~wCrc; /* ISO/IEC 13239 (formerly ISO/IEC 3309) */
*TransmitFirst = (unsigned char) (wCrc & 0xFF);
*TransmitSecond = (unsigned char) ((wCrc >> 8) & 0xFF);
return;
}
int CheckCrc14443(int CrcType, const unsigned char *Data, int Length) {
unsigned char b1;
unsigned char b2;
if (Length < 3) return 0;
ComputeCrc14443(CrcType, Data, Length - 2, &b1, &b2);
if ((b1 == Data[Length - 2]) && (b2 == Data[Length - 1])) return 1;
return 0;
}