Truncated EdDSA/ECDSA Signatures

Thomas Pornin

Paper 2022/938

Truncated EdDSA/ECDSA Signatures

Thomas Pornin, NCC Group

Abstract

This note presents some techniques to slightly reduce the size of EdDSA and ECDSA signatures without lowering their security or breaking compatibility with existing signers, at the cost of an increase in signature verification time; verifying a 64-byte Ed25519 signature truncated to 60 bytes has an average cost of 4.1 million cycles on 64-bit x86 (i.e. about 35 times the cost of verifying a normal, untruncated signature).

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint.
Keywords: EdDSA ECDSA truncated signature
Contact author(s): thomas pornin @ nccgroup com
History: 2022-07-20: approved; 2022-07-19: received; See all versions
Short URL: https://ia.cr/2022/938
License: CC BY

BibTeX

@misc{cryptoeprint:2022/938,
      author = {Thomas Pornin},
      title = {Truncated {EdDSA}/{ECDSA} Signatures},
      howpublished = {Cryptology {ePrint} Archive, Paper 2022/938},
      year = {2022},
      url = {https://eprint.iacr.org/2022/938}
}