github/RRG-Proxmark3
1
0
Fork 0
mirror of https://github.com/RfidResearchGroup/proxmark3.git synced 2025-08-21 05:43:48 -07:00
Code Issues Projects Releases Packages Wiki Activity Actions 4

Remove unnecessary crc

Browse source
This commit is contained in:
Bjoern Kerler 2020-06-13 17:58:47 +02:00
commit e7b2dbd5e8
1 changed files with 2 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

29
client/src/mifare/desfire_crypto.c
View file

@ -881,37 +881,12 @@ void mifare_cypher_blocks_chained(desfiretag_t tag, desfirekey_t key, uint8_t *i
}
}
#define CRC32_PRESET 0xFFFFFFFF
static void
desfire_crc32_byte(uint32_t *crc, const uint8_t value) {
/* x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1 */
const uint32_t poly = 0xEDB88320;
*crc ^= value;
for (int current_bit = 7; current_bit >= 0; current_bit--) {
int bit_out = (*crc) & 0x00000001;
*crc >>= 1;
if (bit_out)
*crc ^= poly;
}
}
#ifndef htole32
#define htole32(x) (x)
#endif
void desfire_crc32(const uint8_t *data, const size_t len, uint8_t *crc) {
uint32_t desfire_crc = CRC32_PRESET;
for (size_t i = 0; i < len; i++) {
desfire_crc32_byte(&desfire_crc, data[i]);
}
*((uint32_t *)(crc)) = htole32(desfire_crc);
crc32_ex(data,len,crc);
}
void desfire_crc32_append(uint8_t *data, const size_t len) {
desfire_crc32(data, len, data + len);
crc32_ex(data, len, data + len);
}
void iso14443a_crc_append(uint8_t *data, size_t len) {