About RC2

RC2 is a block cipher which is trademarked by RSA Data Security. It has a variable keysize and an additional parameter, the "effective number of bits in the RC2 search space", which can take on values in the range 1-1024, inclusive. The effective number of bits in the RC2 search space is sometimes specified by an RC2 "version number"; this "version number" is not the same thing as the "effective number of bits", however. There is a canonical way to convert from one to the other.

RSA Security Inc. Public-Key Cryptography Standards - PKCS#11 - v210