Two Rights Sometimes Make a Wrong
Lars Ramkilde Knudsen, Vincent Rijmen · 1997
At the SAC’96 a new iterated block cipher, Akelarre, was proposed. Akelarre uses components of the block ciphers RC5 and IDEA and is conjectured strong with four rounds. This paper shows that Akelarre with any number of rounds is weak even under a ciphertext only attack. This illustrates that mixing two (presumably) strong ciphers is not always a good idea.