WARNING: Do not use this for cryptography. It is just a demo.
Blowfish is the encryption standard used by KDE Wallet and several other apps. While it provides good security, it is outdated - Twofish and AES are good alternatives. Blowfish is vulnerable to the birthday attack and the known-plaintext attack when small keys are used. Encrypting "encrypt" with password "blowfish" results in "OEFCRkI5NTZCNzE2MEUwOA=="