ZKAttest: Ring and Group Signatures for Existing ECDSA Keys.

Armando Faz-Hernández; Watson Ladd; Deepak Maram

doi:10.1007/978-3-030-99277-4_4

Abstract

Cryptographic keys are increasingly stored in dedicated hardware or behind software interfaces. Doing so limits access, such as permitting only signing via ECDSA. This makes using them in existing ring and group signature schemes impossible as these schemes assume the ability to access the private key for other operations. We present a sigma-protocol that uses a committed public key to verify an ECDSA or Schnorr signature on a message, without revealing the public key. We then discuss how this protocol may be used to derive ring signatures in combination with Groth-Kohlweiss membership proofs and other applications. This scheme has been implemented and source code is freely available.

Citation

@inproceedings{faz_sac2021,
  author = {Armando Faz-Hernández and
            Watson Ladd and
            Deepak Maram},
  title = {ZKAttest: Ring and Group Signatures for Existing ECDSA Keys.},
  booktitle = {Selected Areas in Cryptography - 28th International Conference, SAC 2021. Virtual Event, September 29 - October 1, 2021},
  pages = {68--83},
  editor = {AlTawy, Riham and Hülsing, Andreas},
  publisher = {Springer International Publishing},
  address = {Canada},
  isbn = {978-3-030-99277-4},
  year = {2021},
  month = {oct},
  doi = {10.1007/978-3-030-99277-4_4}
}