[sytelus]

Very low indeed. Chance of SHA1 collision is of the order of 2^52. One person explained it this way: Chance of everyone currently on Earth winning a jackpot in their lifetime is actually higher than a single random SHA1 collision. It should be actually mind boggling how many of the software systems and algorithms rely on hashes and them being not collided.

[yuhong]

I think it is 2^61 now, the paper that once showed the 2^52 attack has removed the claims.