> Actually, I think that what was being argued was that 10 was > insufficient. The original poster was not asking if 20 was sufficient, > he was asking if 10 wasn't sufficient. IMHO... 10 is not sufficient. > The discussion is not over 20, it's over 10. > > Whether 20 is sufficient or not, depends on your use, but it's > better than 10. Arguing that 10 characters is insufficient is NOT arguing > that 20 is sufficient. 20 might be, with decent complexity checkers and > it might not be if it were a clear plaintext passphrase. It might be > total overkill if you are diciplined and have a good enough memory for > high entropy shorter passwords. Certainly 60 bits (10 characters * 6 bits) > is not safe from brute force attacks unless it is protected by other > mechanisms. > > Ppdd wants TWO 24 character passphrases (48 characters or more > total). Is that sufficient? Probably, in most cases. :-) Is it better > than 20? Yeah, I think so, maybe... Does it have any bearing what so > ever on whether or not 10 characters is insufficient? No. > > The argument was over the sufficiency of 10 characters. > Long term, non-volitile, crypto protected by only 60 bits worth of > "key" is subject to being brute force attacked given sufficient > time, equipment, and incentive on the part of the attacker. You > really REALLY want to protect it? You don't use 60 bits. > well, how much time and what equipment would you need for bruteforcing a 10 byte pw? 3 years of ASCI White? ;) [note that im not talkin about distributed computing which is able to decrypt stuff protected by 10 bytes of course] ... and what about 20 bytes then? 10 bytes of a-z and 0-9 thats 36^10=3,656,158,440,062,976 possible passwords... hmm, i'll use 20 bytes and AES128 anyway, but again: is that the minimal length or is it really enough? what about 15 bytes? Linux-crypto: cryptography in and on the Linux system Archive: http://mail.nl.linux.org/linux-crypto/
