Quote:
Originally Posted by kiwidude
Yup, that is exactly what I am saying  64 cases of it in fact in the large library. |
Something is horribly wrong here.
This is the birthday collision problem, and assuming uniform distribution of the hash over the 0..2^256 number space (10^77 unique hashes), you'd need about 10^58 books in your library to have a 50:50 chance of one SHA256 hash collision. With 10^29 books in your library, the chance of one collision is down to one in 10^18.