Provisions: Privacy-preserving proofs of solvency for Bitcoin exchanges

Gaby G.  Dagher; Benedikt Buenz; Joseph Bonneau; Jeremy Clark; Dan Boneh

Paper 2015/1008

Provisions: Privacy-preserving proofs of solvency for Bitcoin exchanges

Gaby G. Dagher, Benedikt Buenz, Joseph Bonneau, Jeremy Clark, and Dan Boneh

Abstract

Bitcoin exchanges function like banks, securely holding their customers' bitcoins on their behalf. Several exchanges have suffered catastrophic losses with customers permanently losing their savings. A proof of solvency demonstrates that the exchange controls sufficient reserves to settle each customer's account. We introduce Provisions, a privacy-preserving proof of solvency whereby an exchange does not have to disclose its Bitcoin addresses; total holdings or liabilities; or any information about its customers. We also propose an extension which prevents exchanges from colluding to cover for each other's losses. We have implemented Provisions and show that it offers practical computation times and proof sizes even for a large Bitcoin exchange with millions of customers.

Metadata

Available format(s): PDF
Publication info: Published elsewhere. Major revision. ACM CCS
Keywords: Bitcoin proof of solvency
Contact author(s): jbonneau @ cs stanford edu
History: 2015-10-26: last of 2 revisions; 2015-10-19: received; See all versions
Short URL: https://ia.cr/2015/1008
License: CC BY

BibTeX

@misc{cryptoeprint:2015/1008,
      author = {Gaby G.  Dagher and Benedikt Buenz and Joseph Bonneau and Jeremy Clark and Dan Boneh},
      title = {Provisions: Privacy-preserving proofs of solvency for Bitcoin exchanges},
      howpublished = {Cryptology {ePrint} Archive, Paper 2015/1008},
      year = {2015},
      url = {https://eprint.iacr.org/2015/1008}
}