Patent ID: 8527766

Claim:
A method, implemented by computing functionality, for reducing leakage of meaningful information from cryptographic operations, comprising: generating an original secret key SK; providing a counterpart key of the original secret key SK; making the counterpart key available to a message-sending entity; modifying the original secret key SK using a pairwise independent hash function to produce a modified secret key SK′, the modified secret key SK′ having individual components, the pairwise independent hash function being given by H K (r)=ar+b or H K (r)=A r *B, where a, b, A, B, and r are selected values and H K refers to a hash function that is keyed by a key K; storing a modified secret key collection, which includes the modified secret key SK′ and one or more of selected values a, b, A, B, and r; receiving ciphertext information that includes an encrypted message from the message-sending entity, the encrypted message being created based on the counterpart key; and decrypting the encrypted message by performing plural partial operations using members of the modified secret key collection to generate plural respective partial operation results, the encrypted message being decrypted based on a combination of the plural partial decryption results, leakage of meaningful information being reduced due to difficulty in assembling meaningful information from separate leakage information leaked from the respective plural partial operations.