Paper 2022/546
He-HTLC: Revisiting Incentives in HTLC
Sarisht Wadhwa, Jannis Stoeter, Fan Zhang, and Kartik Nayak
Abstract
Hashed Time-Locked Contracts (HTLCs) are a widely used primitive in blockchain systems. Unfortunately, HTLC is incentive-incompatible and is vulnerable to bribery attacks. MAD-HTLC (Oakland'21) is an elegant solution aiming to address the incentive incompatibility of HTLC. In this paper, we show that MAD-HTLC is also incentive-incompatible. The crux of the issue is that MAD-HTLC only considers passively rational miners. We argue that such a model fails to capture active rational behaviors. We demonstrate the importance of taking actively rational behaviors into consideration by showing three novel reverse-bribery attacks against MAD-HTLC that can be implemented using Trusted Execution Environments (TEEs) or zero-knowledge proofs (ZKPs). We further show that reverse bribery can be combined with original delaying attacks to render MAD-HTLC insecure regardless of the relationship between collateral and deposit. Based on the learnings from our attacks, we devise a new smart contract specification, He-HTLC, which is lightweight and inert to incentive manipulation attacks. HE-HTLC, according to us, is the first specification to meet the HTLC specification even in the presence of actively rational miners.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- Preprint. MINOR revision.
- Keywords
- fair exchangeblockchainsHTLC
- Contact author(s)
-
sarisht wadhwa @ duke edu
fan zhang @ duke edu
kartik @ cs duke edu
jannis stoeter @ alumni duke edu - History
- 2022-05-20: last of 2 revisions
- 2022-05-10: received
- See all versions
- Short URL
- https://ia.cr/2022/546
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2022/546,
author = {Sarisht Wadhwa and Jannis Stoeter and Fan Zhang and Kartik Nayak},
title = {He-HTLC: Revisiting Incentives in HTLC},
howpublished = {Cryptology ePrint Archive, Paper 2022/546},
year = {2022},
note = {\url{https://eprint.iacr.org/2022/546}},
url = {https://eprint.iacr.org/2022/546}
}
