Re:Everything you need to know about cryptography in 1 hour
by cperciva on Friday May 14, 2010 @04:18AM
(#1346872)
With a 128-bit block, you can send 2^64 messages of up to 2^64 blocks each; that's not going to cause problems. With a 64-bit block, you're limited to 2^32 messages of up to 2^32 blocks before you overflow.
Forgive my ignorance, but why is having a short block size especially bad? You don't want to subject 64 bits to a birthday attack, but something like CTR mode should work, right? (I still wouldn't recommend Blowfish - AES is used more widely and works perfectly well - I'd just like to understand your reasoning).