-1
$\begingroup$

CRC32 has hash collisions for the inputs "plumless" and "buckeroo". What's the smallest data length for collisions in MD4, MD5, SHA-1, and the recently accepted SHA-3 (Keccak)? We know that lim_len n->infty p(collision) = 1.0, but I'm curious how large your data has to be before a particular hash algorithm actually experiences a collisions.

Can MD4 collide on blocks less than 100 byes? 1000? 10^10? 10^20? ...

1 Answers 1

1

The range of MD4 is 128 bits or 16 bytes. That means that it necessarily collides on inputs of length 17 bytes or less. Heuristically, we expect it to collide on inputs of length 9 bytes or less (assuming it approximates a random function).

  • 0
    Hash-based sync software is an engineering solution - it works and it's efficient. The only other solution is to compare a (losslessly) compressed version of the complete files, or a complete overhaul of the system.2012-10-13