Fast post-quantum cryptographic sortition

Abstract

A method for cryptographic sortition among a group of parties includes committing, by a first party, to a set of n party-specific secret keys k1, kn for a block cipher E and obtaining, by the first and a second party, a common input x and an index r. The method further includes encrypting, by the first party, the input x with the r-th key kr of the committed keys k1, . . . , kn, thereby generating an output y1 of the block-cipher E, and publishing the output y1 with the key kr used for encryption. The method further includes encrypting, by the second party, the common input x with the published key kr, thereby generating an output y1′ of the block-cipher E, and comparing the generated output y1′ with the published output y1. The method can be used to optimize the cryptographic sortition and support secure decision making.

CPC Classifications