Cryptanalysis of fast encryption algorithm for multimedia FEA-M

Certain weaknesses in the algebraic structure of the previously proposed fast encryption algorithm for multimedia FEA-M are pointed out. It is shown that, when the secret key consists of k bits, under realistic chosen and known plaintext attacks, the secret key recovery has complexity proportional to 2k/sup 2/ and k/sup 4/, respectively, implying that FEA-M is an insecure algorithm even if the secret keys of 4096 bits are employed.