Interface compatible approach for gluing white-box implementation to surrounding program

A method of producing a cryptographic implementation of a cryptographic operation mapping an input message to an output message in a cryptographic system that glues the cryptographic implementation to a surrounding program, comprising:

• producing a cryptographic implementation of the keyed cryptographic operation including a plurality of functions;
• receiving information specifying a computed value wherein a first function depends on the computed value;
• modifying the cryptographic implementation to receive the computed value from the surrounding program;
• and
• modifying the cryptographic implementation based upon the received computed value so that:
• when a received computed value is equal to the desired value, the cryptographic implementation outputs a correct output message;
• and
• when a received computed value is not equal to the desired value, the cryptographic implementation outputs an incorrect output message.

A non-transitory machine-readable storage medium encoded with instructions for execution by a cryptographic implementation performing a cryptographic function in a cryptographic system for gluing a cryptographic implementation to a surrounding program in a cryptographic system, the non-transitory machine-readable storage medium comprising:

• instructions for receiving, by the cryptographic system, an input message;
• instructions for receiving a computed value from the surrounding program;
• instructions for performing, by the cryptographic system, a keyed cryptographic operation mapping the input message into an output message using the computed value from the surrounding program, wherein the output message is a correct output message when the computed value has a correct value;
• and
• instructions for outputting the output message.