A method and apparatus for reducing a variable number of pre-key bits to a fix key size is disclosed. The resulting key is used with a symmetric block cipher to descramble content. By being able to directly adapt a large and variable number of bits, it is possible to use cryptographic algorithms that were not thought possible, such as the output of modem public key and hashing functions, in order to create a key to directly use with a symmetric block cipher. Some or all of the pre-key bits may be used in the creation of the key.