🚀 go-pugleaf

leichter@zodiac.rutgers.edu writes:
>....  (Actually, "meet in the middle"
>attacks show that double encryption, done this way, cannot be MUCH stronger
>than single encryption - though it may be SOMEWHAT stronger.)

>							-- Jerry
Since the total number of possible encrypting functions of 64 bits is
something like (2^64)!, and there are only 2^56 DES encryption
functions and multiple DES is half the set of all encryptions, I would
expect (naively) that double encryption would essentially be as strong
as a key with 2*56=112 bits, unless DES is almost a group ( ie most
double encryptions yield the same encryption as some single DES). Why is
this argument wrong, or is DES almost a group in the above sense?