Rodrigo, was there anything wrong with my answer below (and others equal), apart from it not being the one you wanted, since you keep repeating the same question over and over again?
Do you have a better answer? Please share it for us to check. On Tue, Sep 17, 2013 at 03:58:34PM +0200, Raimo Niskanen wrote: > On Tue, Sep 17, 2013 at 01:21:04PM +0000, hru...@gmail.com wrote: > > Raimo Niskanen <raimo+open...@erix.ericsson.se> wrote: > > > > > When you have two different real world contents the collision probability > > > is just that; 2^-160 for SHA-1. It is when you deliberately craft a > > > second content to match a known hash value there may be weaknesses > > > in cryptographic hash functions, but this is not what rsync nor Git > > > does, as Marc Espie pointed out in this thread. > > > > You have strings A and B, and you know only that hash(A)=hash(B): what > > is the probability that A=B? 2^-160? > > You have to mean "what is the probability that A != B", and it is 2 ^ (-160). > > If you actually mean what you wrote, the probability of A = B is > 1 - (2 ^ (-160)), which is as said earlier in this thread higher than > what you get when storing the string on disk and then reading it back. > > > > > Rodrigo. > > -- > > / Raimo Niskanen, Erlang/OTP, Ericsson AB -- / Raimo Niskanen, Erlang/OTP, Ericsson AB
