Dan Boneh's courersa lecture on format preserving encryption at 5.50 mins , talks about truncating a PRF on n bits to PRF on t bits. The approach is by appending (n-t) zeros to input t bits then ...
Are the proofs based on a PRF assumption still valid when using a variable-length input PRF ? The answer is maybe obvious but I have a doubt.
I've seen that there is several kind of PRFs. Sometimes people speak about strong PRFs. When proofs of a protocol or algorithm are given based on the assumption of the use of a PRF, they speak ...