The Blowfish Algorithm sounds like the latest Dan Brown thriller, or the next James Bond movie or the working subtitle of Tom Cruise’s current Mission Impossible caper.
It’s not far off either - Blowfish encryption is all about keeping spies, thieves, government agencies and bald megalomaniacs out of your data.
Blowfish first appeared on the cryptographic scene all the way back in 1993 as a symmetric key block cipher. At the time, Blowfish was unusual in that the code was public domain, meaning that anyone could use it, rather than commercial, proprietary or government ownership.
The Blowfish algorithm encrypts blocks of 64 bits (eight characters), with key sizes ranging from 32 bits to 448 bits.
Each 64-bit plaintext block is divided into two parts - a left side and a right side - each of 32 bits.
The left side and the right side have mathematical substitutions and other functions applied to them and their outputs are swapped - the right-hand side output becoming the new input for the left hand side and vice versa.
This happens a total of 16 times.
Encryption with Blowfish is fast, except when generating new keys.
It was succeeded by the far less sinister-sounding TwoFish in 1998.