Paper 2002/129
Key-collisions in (EC)DSA: Attacking Non-repudiation
Tomas Rosa
Abstract
A new kind of attack on the non-repudiation property of digital signature schemes is presented. We introduce a notion of key-collisions, which may allow an attacker to claim that the message (presented to a judge) has been signed by someone else. We show how to compute key-collisions for the DSA and ECDSA signature schemes effectively. The main idea of these attacks has been inspired by the well-known notion of message-collisions, where an attacker claims that the signature presented at the court belongs to a different message. Both of these collision-based attacks significantly weaken the non-repudiation property of signature schemes. Moreover, they weaken the non-repudiation of protocols based on these schemes. It is shown that key-collision resistance of the (EC)DSA schemes requires the incorporation of a mechanism ensuring honest generation of (EC)DSA instances. The usage of such a mechanism shall be verifiable by an independent third party without revealing any secret information. We propose and discuss basic general countermeasures against key-collision attacks on the (EC)DSA schemes.
Metadata
- Available format(s)
-
PDF
- Publication info
- Published elsewhere. Paper supports a talk given at CRYPTO 2002 Rump Session (was: On Key-collisions in (EC)DSA Schemes)
- Keywords
- digital signaturesnon-repudiation
- Contact author(s)
- t_rosa @ volny cz
- History
- 2004-01-10: last of 2 revisions
- 2002-08-26: received
- See all versions
- Short URL
- https://ia.cr/2002/129
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2002/129,
author = {Tomas Rosa},
title = {Key-collisions in ({EC}){DSA}: Attacking Non-repudiation},
howpublished = {Cryptology {ePrint} Archive, Paper 2002/129},
year = {2002},
url = {https://eprint.iacr.org/2002/129}
}
