Paper 2018/987

Fast Secure Multiparty ECDSA with Practical Distributed Key Generation and Applications to Cryptocurrency Custody

Iftach Haitner, Coinbase, Tel Aviv University
Yehuda Lindell, Coinbase
Ariel Nof, Bar-Ilan University
Samuel Ranellucci, Coinbase
Abstract

ECDSA is a standardized signing algorithm that is widely used in TLS, code signing, cryptocurrency and more. Due to its importance, the problem of securely computing ECDSA in a distributed manner (known as threshold signing) has received considerable interest. Despite this interest, however, as of the time of publication of the conference version of this paper ([Lindel and Nof, ACM SIGSAC 18'), there had been no full threshold solution for more than two parties (meaning that any t-out-of-n parties can sign, security is preserved for any t−1 or fewer corrupted parties, and t ≤ n can be any value) that supports practical key distribution. All previous solutions for this functionality utilized Paillier homomorphic encryption, and efficient distributed Paillier key generation for more than two parties is not known. In this paper, we present the first (again, for the conference version publication time) truly practical full threshold ECDSA signing protocol that has fast signing and key generation. This solves an old open problem and opens the door to many practical uses of threshold ECDSA signing that are in demand today. One of these applications is the construction of secure cryptocurrency wallets (where key-shares are spread over multiple devices, and so are hard to steal) and cryptocurrency custody solutions (where large sums of invested cryptocurrency are strongly protected by splitting the key between a bank/financial institution, the customer who owns the currency, and possibly a third-party trustee, in multiple shares at each). There is growing practical interest in such solutions, but prior to our work, these could not be deployed due to the need for a distributed key generation.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Published elsewhere. ACM CCS 2018
DOI
10.1145/3243734.3243788
Keywords
ECDSAthreshold cryptography
Contact author(s)
iftachh @ gmail com
yehuda lindell @ coinbase com
ariel nof @ biu ac il
samuel ranellucci @ coinbase com
History
2023-05-29: revised
2018-10-18: received
See all versions
Short URL
https://ia.cr/2018/987
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2018/987,
      author = {Iftach Haitner and Yehuda Lindell and Ariel Nof and Samuel Ranellucci},
      title = {Fast Secure Multiparty ECDSA with Practical Distributed Key Generation and Applications to Cryptocurrency Custody},
      howpublished = {Cryptology ePrint Archive, Paper 2018/987},
      year = {2018},
      doi = {10.1145/3243734.3243788},
      note = {\url{https://eprint.iacr.org/2018/987}},
      url = {https://eprint.iacr.org/2018/987}
}
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