COUNTERMEASURES AGAINST SIDE-CHANNEL ATTACKS ON CRYPTOGRAPHIC ALGORITHMS USING PERMUTATIONS

Techniques for encrypting data are provided that can be used to help prevent side-channel attacks on the cryptographic algorithms. An example method according to these techniques includes permuting an order of first intermediate data according to a predetermined permutation to produce permuted intermediate data. The first inter mediate data is output by one or more first stages of a cryptographic algorithm. The method also includes permuting a key to be used by one or more second stages of a cryptographic algorithm according to the predetermined permutation, applying the one or more second stages of a cryptographic algorithm to the permuted intermediate data to generate second intermediate data, the one or more second stages of the cryptographic algorithm using the permuted key, and permuting the second intermediate data according to an inverse permutation of the predetermined permutation to generate output.