On 19/03/2013 00:50, [email protected] wrote: > So, my problem is to create a format-preserving injective function > which is non-invertible (at least computationally). > > Since it's format preserving, it has to be a bijection, I'm guessing > that basically boils down to a (computationally strong?) random > permutation, for a domain of size =/= 2^n.
A hash with n-bit result, with input domain restricted to n-bit, with n>=200 or so, is not a bijection, but is computationally indistinguishable from what Iunderstand is your requirement. Do I miss something?Or do you want it to be demonstrably format-preserving/bijective(rather than computationally indistinguishable from that)? http://crypto.stackexchange.com would be another nice place to ask. Francois Grieu _______________________________________________ cryptography mailing list [email protected] http://lists.randombit.net/mailman/listinfo/cryptography
