X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/fdcc61d3189f7e91db27a865c25d923849ec47d5..e1778858ddc53a6a82e8ee24f02e6b673687f69a:/common/iso14443crc.c

diff --git a/common/iso14443crc.c b/common/iso14443crc.c
index f91b3ce1..d07a2871 100644
--- a/common/iso14443crc.c
+++ b/common/iso14443crc.c
@@ -1,6 +1,14 @@
+//-----------------------------------------------------------------------------
+// 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)
+unsigned short UpdateCrc14443(unsigned char ch, unsigned short *lpwCrc)
 {
     ch = (ch ^ (unsigned char) ((*lpwCrc) & 0x00FF));
     ch = (ch ^ (ch << 4));
@@ -10,7 +18,7 @@ static unsigned short UpdateCrc14443(unsigned char ch, unsigned short *lpwCrc)
 }
 
 void ComputeCrc14443(int CrcType,
-                     unsigned char *Data, int Length,
+                     const unsigned char *Data, int Length,
                      unsigned char *TransmitFirst,
                      unsigned char *TransmitSecond)
 {
@@ -29,3 +37,12 @@ void ComputeCrc14443(int CrcType,
     *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;
+}