Blowfish is a block cipher designed in 1993 to be fast on the general purpose CPUs of the time. It features a 64 bits block size and a variable key size up to 448 bits.
One should likely not use use Blowfish in any new designs, to quote Bruce Schneier its designer in a 2007 interview,
There weren't enough alternatives to DES out there. I wrote Blowfish as such an alternative, but I didn't even know if it would survive a year of cryptanalysis. Writing encryption algorithms is hard, and it's always amazing if one you write actually turns out to be secure. At this point, though, I'm amazed it's still being used. If people ask, I recommend Twofish instead.
One should note that Twofish was one of the losing contestant to the AES competition, so the general cryptography community would likely recommend aes instead of twofish.
