from Hacker News

A Hash160 Collision

by vlugorilla on 4/5/25, 6:39 PM with 4 comments

  • by vessenes on 4/5/25, 8:26 PM

    @mods this title is the title of the page. However, it is an extremely misleading title for the content, which describes the math of searching for a RIPEMD160 collision, and in no way announces the successful finding of such a collision — an event that would be a major market mover in crypto.

    I suggest maybe adding “: calculating the odds of success” or something.

  • by susam on 4/5/25, 7:30 PM

    > Obviously, the probability for this to happen is 1 in 2^256, which is such a ridiculously small number, that there is nothing in the physical world to describe it by example.

    Here is my attempt. Take a deck of 52 cards. Pick 5 more cards from another deck of a different brand. So now we have 57 distinct cards. Assume that the 57 cards are shuffled thoroughly in a random and uniform manner, meaning that each permutation of the 57 cards is equally likely.

    What are the odds of you guessing all 57 cards in the correct sequence purely by chance? Turns out the odds of you guessing the entire sequence of 57 shuffled cards are better than 1 in 2^256.

    In fact, 57! < 2^256 < 58!.

  • by gnabgib on 4/5/25, 6:49 PM