| 摘要 |
A Feistel network arrangement comprising dividing a block of data (e.g. plaintext) into initial left Li and right Ri halves, and calculating updated left Li+1 and right Ri+1 halves for each of a plurality of rounds i. Calculating the updated left half includes applying a first function F to an input left half to produce a first result, and mixing (e.g. adding or XORing) the first result with the input right half. Calculating the updated right half includes applying a second function G to the input left half to produce a second result, and mixing (e.g. adding or XORing) the second result with a round key ki. The input left and right halves are the initial left and right halves for the first round i, and thereafter the updated left and right halves for an immediately preceding round i-1. The method may include producing a block of ciphertext with a key composed of the updated left Li+1 and right Ri+1 halves for the last round or producing a ciphertext composed of the updated left and right halves for the last of the plurality of rounds. The first function may be a non-linear function that may or may not be invertible and the second function may be an invertible function. |
