Paper 2013/730 Original: eprint.iacr.org/2013/730 ↗
Stamp \& Extend -- Instant but Undeniable Timestamping based on Lazy Trees
Abstract
We present a Stamp\&Extend time-stamping scheme based on linking via modified creation of Schnorr signatures. The scheme is based on lazy construction of a tree of signatures. Stamp\&Extend returns a timestamp immediately after the request, unlike the schemes based on the concept of timestamping rounds. Despite the fact that all timestamps are linearly linked, verification of a timestamp requires a logarithmic number of steps with respect to the chain length. An extra feature of the scheme is that any attempt to forge a timestamp by the Time Stamping Authority (TSA) results in revealing its secret key, providing an undeniable cryptographic evidence of misbehavior of TSA. Breaking Stamp\&Extend requires not only breaking Schnorr signatures, but to some extend also breaking Pedersen commitments.
Metadata
- Available format(s)
PDF- Category
- Cryptographic protocols
- Publication info
- Preprint.
- History
- 2013-11-13: last updated
- 2013-11-13: published
- Short URL
- https://ia.cr/2013/730
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2013/730,
author = {Łukasz Krzywiecki and Przemys{\l}aw Kubiak and Miros{\l}aw Kuty{\l}owski},
title = {Stamp \& Extend -- Instant but Undeniable Timestamping based on Lazy Trees},
howpublished = {Cryptology {ePrint} Archive, Paper 2013/730},
year = {2013},
url = {https://eprint.iacr.org/2013/730}
}