ENCODING METHOD AND SYSTEM RESISTANT TO POWER ANALYSIS

摘要

New techniques for cracking sealed platforms have recently been discovered which observe power modulation during execution of a software encryption program on a computer processor. Particularly vulnerable to such simple power analysis and differential power analysis attacks are smart cards which employ Data Encryption Standard (DES) protection. The invention protects against such attacks by mapping data onto "Hamming-neutral" values, that is, bytes which have the same number of 1-values, so power signatures do not vary during execution. The Hamming-neutral values are assigned to each bit-string in a targeted data set, rather than in a bit-wise manner as known. This approach has a number of advantages: it is less demanding of system resources, it results in a larger number of encodings for an attacker to decipher, and it can be applied to various components including: addressing, indexing, stored data and input data. Many variations and improvements are also described.