160 bit
hash function created in
Europe by [Hans Dobbertin]
?, [Antoon Bosselaers]
? and [Bart Preneel]
?.
It's similar in both strength and performance to more popular
SHA-1. Because creation of
RIPEMD-160 was
more open than of
SHA-1, one may expect that it's less likely that designers left some secret hole in algorithm.
On the other hand, as it is less popular, less
cryptographers tried to find hole in it,
so it's more likely that some unplanned unknown hole exist in algorithm.
There also exist 128, 256 and 320 bit versions of this algorithm, called RIPEMD-128?, RIPEMD-256? and RIPEMD-320? respectively. 256 and 320 bit versions only diminish chance of accidental collision?, and don't increase security in any way as compared to, respectively, RIPEMD-128? and RIPEMD-160.
RIPEMD isn't restrained by any patents.