On the Design and Security of RC2

. The block cipher RC2 was designed in 1989 by Ron Rivest for RSA Data Security Inc. In this paper we describe both the cipher and preliminary attempts to use both differential and linear cryptanalysis. 1 Introduction RC2 is a block cipher 5 that was designed in 1989 by Ron Rivest for RSA Data Security, Inc. Initially held as a confidential and proprietary algorithm, RC2 was published as an Internet Draft during 1997 [12]. RC2 has many interesting and unique design features, particularly so when one considers the style of ciphers that dominated both the literature and the market at the time of its invention. The cipher was intended to be particularly efficient on 16-bit processors and with a 64-bit block size it was intended as a drop-in replacement for DES [11]. A significant feature of RC2 is the flexibility offered to the user in terms of the effective key-size. This has now become a common feature of many block cipher proposals and it is a property that has proven to be importan..