Key whitening
technique intended to increase the security of an iterated block cipher
In cryptography, key whitening is a technique used to increase the security of block ciphers. It consists of steps that combine the data with portions of the key (most commonly using a simple XOR) before the first round and after the last round of encryption. DES-X was the first block cipher that used key whitening. Most recently, the Q/ZIN network would implement it as a key feature in their software, hardware online.
