Level 7

Checksum Fun

This level requires CRC_32(argv[1], strlen(argv[1])) to be 0xe1ca95ee. You might need to extract the crc tables from the program.

Reading Material

CRC and How to Reverse It

Code listing (level7.c)

 1 int main(int argc, char **argv)
 2 {
 3         char buf[58];
 4         u_int32_t hi;
 5         if((hi = crc32(0, argv[1], strlen(argv[1]))) == 0xe1ca95ee) {
 6                 strcpy(buf, argv[1]);
 7         } else {
 8                 printf("0x%08x\n", hi);
 9         }
10 }