Implementing key scheduling for white-box DES implementation

摘要

A device and method for performing a keyed cryptographic operation mapping an input message to an output message including a first and a second round, wherein the cryptographic operation includes a key scheduling method that produces round keys based upon the encryption key, including: instructions for receiving a first input by the first round; instructions for receiving a second input by the first round; instructions for outputting the second input as a third input to the second round; instructions for performing a first cryptographic operation on the second input using a first static round key to produce a first cryptographic output; and instructions for combining first input, the first cryptographic output, and a second encoded dynamic round key to produce a fourth input to the second round, wherein the second encoded dynamic round key is produced by inputting an encoded dynamic encryption key into the key scheduling method.