- DEFINE BLUEFISH 64 BITS
- DEFINE BLUEFISH FULL
- DEFINE BLUEFISH FREE
DEFINE BLUEFISH 64 BITS
Initially, the input "Hi world" consists of seven characters plus one space, which is equal to 64 bits or 8 bytes. In total, Blowfish runs 521 times to generate all the subkeys and processes - about 4 kilobytes (KB) of data.īlowfish encryption/decryption process exampleĪssume the message "Hi world" is to be encrypted with Blowfish. This process continues until all the P-arrays and four S-boxes are modified. The output of step 5 modifies P3 and P4 in the P-array. This output is encrypted by Blowfish with modified subkeys. P1 and P2 arrays are replaced with the output from step 3 above. All-zero strings are encrypted by the algorithm as described in the above steps. The first element in the P-array (P1) is now XORed with the first 32 bits of the key, P2 is XORed with the second 32-bits and so on, until all the elements in the P-array are XORed with the key bits. The P-array and S-boxes are initialized with a fixed string of hexadecimal digits of pi. In Blowfish, the P-array consists of 18 32-bit subkeys and four 32-bit S-boxes with 256 entries each. These subkeys are pre-computed before encryption or decryption can take place. Subkeys form an integral part of the Blowfish algorithm, which uses a large number of them. In the key expansion process, maximum size 448-bit keys are converted into several subkey arrays totaling 4,168 bytes. All encryption operations are XORs - a type of logic gate - and additions on 32-bit words. Large, key-dependent S-boxes work with the substitution method and form an integral part of the data encryption system in Blowfish. Data encryption happens through a 16-round Feistel network, with each round consisting of a key-dependent permutation and a key- and data-dependent substitution. The Blowfish algorithm consists of two major parts: How block ciphers like Blowfish and Twofish work Blowfish uses a single encryption key to both encrypt and decrypt data. It consists of 16 Feistel-like iterations, where each iteration operates on a 64-bit block that's split into two 32-bit words. Understanding Blowfishīlowfish features a 64-bit block size and takes a variable-length key, from 32 bits to 448 bits. DEFINE BLUEFISH FULL
Nonetheless, full Blowfish encryption has never been broken, and the algorithm is included in many cipher suites and encryption products available today. Twofish, its successor, addressed the security problem with a larger block size of 128 bits.
However, it couldn't completely replace DES due to its small block size, which is considered insecure.
DEFINE BLUEFISH FREE
Designed by Bruce Schneier in 1993 as a "general-purpose algorithm," it was intended to provide a fast, free, drop-in alternative to the aging Data Encryption Standard ( DES) and International Data Encryption Algorithm ( IDEA) encryption algorithms.īlowfish is significantly faster than DES and IDEA and is unpatented and available free for all uses.
Blowfish is a variable-length, symmetric, 64-bit block cipher.
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