Cryptography
Blowfish
Definition
A 64-bit-block, variable-key-length Feistel cipher designed by Bruce Schneier in 1993; secure cryptanalytically but limited by a small block size and superseded by AES.
Examples
- Older versions of OpenSSH and OpenVPN supported Blowfish in CBC mode.
- The bcrypt password hash derives its key schedule from Blowfish.
Related terms
Twofish
A 128-bit-block, 128/192/256-bit-key symmetric cipher designed by Schneier et al. as an AES competition finalist; secure but rarely used because AES became the standard.
AES (Advanced Encryption Standard)
A NIST-standardized 128-bit block cipher with 128-, 192- or 256-bit keys, designed by Daemen and Rijmen and used as the dominant symmetric cipher worldwide.
Block Cipher
A symmetric cipher that encrypts fixed-size blocks of plaintext with a secret key, usually combined with a mode of operation to handle data of arbitrary length.
Symmetric Encryption
An encryption scheme in which the same secret key is used for both encryption and decryption, offering high speed and strong confidentiality when the key is shared securely.
Encryption
The cryptographic transformation of plaintext into ciphertext using an algorithm and key so that only authorized parties can recover the original data.
bcrypt
An adaptive password-hashing function based on the Blowfish cipher with a tunable cost factor, designed by Provos and Mazières in 1999.