Mix-Nets from Re-randomizable and Replayable CCA-Secure Public-Key Encryption

Antonio Faonio (1) , Luigi Russo (1)

1 Eurecom [Sophia Antipolis]

Mix-nets are protocols that allow a set of senders to send messages anonymously. Faonio et al. (ASIACRYPT'19) showed how to instantiate mix-net protocols based on Public-Verifiable Re-randomizable Replayable CCA-secure (Rand-RCCA) PKE schemes. The bottleneck of their approach is that public-verifiable Rand-RCCA PKEs are less efficient than typical CPA-secure re-randomizable PKEs. In this paper, we revisit their mix-net protocol, showing how to get rid of the cumbersome public-verifiability property, and we give a more efficient instantiation for the mix-net protocol based on a (non publicly-verifiable) Rand-RCCA scheme. Additionally, we give a more careful security analysis of their mix-net protocol.

Domaines: Ingénierie assistée par ordinateur

Antonio Faonio, Luigi Russo. Mix-Nets from Re-randomizable and Replayable CCA-Secure Public-Key Encryption. SCN 2022, 13th Conference on Security and Cryptography for networks, Sep 2022, Amalfi, Italy. pp.172-196, ⟨10.1007/978-3-031-14791-3_8⟩. ⟨hal-03772345⟩