Created
November 30, 2023 05:16
-
-
Save bettse/a3ce6b4f728586fd045ecffdc4441132 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #include <stdlib.h> | |
| #include <stdio.h> | |
| #include <string.h> | |
| #include <inttypes.h> | |
| #if defined(__APPLE__) | |
| #include <libkern/OSByteOrder.h> | |
| #define bswap_16(x) OSSwapInt16(x) | |
| #define bswap_32(x) OSSwapInt32(x) | |
| #define bswap_64(x) OSSwapInt64(x) | |
| #else | |
| #include <byteswap.h> | |
| #endif | |
| #define HEX 0x10 | |
| #define UID_LEN 4 | |
| #define SECTOR_COUNT 16 | |
| #define KEY_MASK 0xFFFFFFFFFFFF | |
| #define POLY UINT64_C(0x42f0e1eba9ea3693) | |
| #define TOP UINT64_C(0x800000000000) | |
| uint64_t crc64_like(uint64_t result, uint8_t sector) { | |
| result ^= (uint64_t)sector << 40; | |
| for(int i = 0; i < 8; i++) { | |
| result = (result & TOP) ? (result << 1) ^ POLY : result << 1; | |
| } | |
| return result; | |
| } | |
| uint64_t taghash(uint32_t uid) { | |
| uint64_t result = 0x9AE903260CC4; | |
| uint8_t uidBytes[UID_LEN] = {0}; | |
| memcpy(uidBytes, &uid, UID_LEN); | |
| for(int i = 0; i < UID_LEN; i++) { | |
| result = crc64_like(result, uidBytes[i]); | |
| } | |
| return result; | |
| } | |
| int main(int argc, char *argv[]) { | |
| if (argc != 2) { | |
| printf("%s <4 byte uid in hex>\n", argv[0]); | |
| return 1; | |
| } | |
| uint32_t uid = strtoul(argv[1], NULL, HEX); | |
| printf("uid = %08x\n", uid); | |
| printf("Sector 0: 4b0b20107ccb\n"); //Fixed sector 0 key | |
| uid = bswap_32(uid); | |
| uint64_t hash = taghash(uid); | |
| for(uint8_t sector = 1; sector < SECTOR_COUNT; sector++) { | |
| uint64_t sectorhash = crc64_like(hash, sector); | |
| uint64_t key = bswap_64(sectorhash & KEY_MASK) >> 16; | |
| printf("Sector %u: %012" PRIx64 "\n", sector, key); | |
| } | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment