Method of generating a correspondence table for a cryptographic white box

摘要

A method is provided for generating a correspondence table suitable for use in a cryptographic processing method and comprising storing a plurality of input data and of output data in the table, each input datum being associated with at least one output datum in the table. For each input datum, at least one of the output data is obtained by applying a coding function to a first subsidiary datum and to an encrypted intermediate datum depending on the input datum. Also provided are a corresponding encryption method, a storage unit suitable for storing the correspondence table generated by the above generation method, a device for physically implementing such a correspondence table, a decryption device including such a storage unit, and a computer program product suitable for implementing the above generation method.

主权项

1. A method of generating a correspondence table suitable for use in a cryptographic processing method and comprising:
storing a plurality of input data and of output data in the table; associating each said input datum with a plurality of said output data in the table; for each said input datum, generating, using a processor of a computer, a plurality of distinct first subsidiary data and a plurality of distinct second subsidiary data, and obtaining an encrypted intermediate datum depending on the input datum; for each said generated first subsidiary datum, obtaining the plurality of output data by applying, with the processor, a coding function to said first subsidiary datum and to the encrypted intermediate datum depending on the input datum; and for each of said generated second subsidiary data, obtaining a plurality of coded input data by applying, with the processor, a further coding function to said second subsidiary datum and to the input datum.