BlowFish (EN)
Posted by , Last modified by AceBIT GmbH on 10 February 2018 12:27


BlowFishBlowFish/TwoFish is a widespread security algorithm which was published by Bruce Schneier in the beginning of the year 1994. This algorithm works similar to DES and it uses block coding with blocks of a size of 64 bit. BlowFish was spread very fast after its publication, due to the fact that Bruce Schneier is one of the most famous cryptology experts and that this algorithm can be used without paying a licence fee. In addition, using this algorithm data can be en and decoded with high speed. If the routine for BlowFish is implemented in software, a disk space of less than five kilobytes is sufficient. You can vary the size of the key as as you like up to 448 bits. That is why this algorithm with its 2,448 different possibilities is protected against any brute force attacks. This is how the encryption algorithm BlowFish works:BlowFish defines two different S boxes, a P box and four S boxes. The P box P is a onedimensional field with 18 32bit values. The boxes contain accidental values, which are implemented in the code or generated during each initialization. The S boxes S1, S2, S3, S4 each contain 256 32bit values. The BlowFish initialization looks like this:
BlowFish encryption (block size: 64 bits, rounds (r): 16):
Explanation of function f:
For decoding data, the entire process is performed vice versa.  
