14-06-2013, 02:49 PM
BLOWFISH ALGORITHM ENCRYPTION
BLOWFISH ALGORITHM.pptx (Size: 72.5 KB / Downloads: 27)
The diagram to the right shows Blowfish's F-function. The function splits the 32-bit input into four eight-bit quarters, and uses the quarters as input to the S-boxes.
The outputs are added modulo 232 and XORed to produce the final 32-bit output.
Since Blowfish is a Feistel network, it can be inverted simply by XORing P17 and P18 to the ciphertext block, then using the P-entries in reverse order.