Key Compression for Isogeny-Based Cryptosystems

Abstract. With the impending threat of quantum computers, Post-Quantum Cryptography schemes have emerged as suitable replacements for today’s public-key cryptography schemes. We present a method for key compression in quantum-resistant isogeny-based cryptosystems, which reduces storage and transmission costs of perparty public information by a factor of two, with no effect on security. We achieve this reduction by associating a canonical choice of elliptic curve to each j-invariant, and representing elements on the curve as linear combinations with respect to a canonical choice of basis. This method of compressing public information can be applied to numerous isogeny-based protocols, such as key exchange, zero-knowledge identification, and public-key encryption. We performed personal computer and ARM implementations of the key exchange with compression and decompression in C and provided timing results, showing the computational cost of key compression and decompression at various ...

• Type: Journal
• Year: 2016
• Where: IACR
• Authors: Reza Azarderakhsh, David Jao, Kassem Kalach, Brian Koziel, Christopher Leonardi
• Keywords: Biometrics, IACR 2016