RC2
RC2 uses key-expansion algorithm by which an expanded key consisting of 64 (16-bit words) is produces depending in a complicated way on every bit of the supplied "variable-length" input key. A mixing round consists of four applications of the "mix-up" transformation, as shown in the diagram. A round is "mashed" by adding to it one of the 16-bit words of the expanded key (RFC 2268).