---
_id: '8322'
abstract:
- lang: eng
  text: "Reverse firewalls were introduced at Eurocrypt 2015 by Miro-nov and Stephens-Davidowitz,
    as a method for protecting cryptographic protocols against attacks on the devices
    of the honest parties. In a nutshell: a reverse firewall is placed outside of
    a device and its goal is to “sanitize” the messages sent by it, in such a way
    that a malicious device cannot leak its secrets to the outside world. It is typically
    assumed that the cryptographic devices are attacked in a “functionality-preserving
    way” (i.e. informally speaking, the functionality of the protocol remains unchanged
    under this attacks). In their paper, Mironov and Stephens-Davidowitz construct
    a protocol for passively-secure two-party computations with firewalls, leaving
    extension of this result to stronger models as an open question.\r\nIn this paper,
    we address this problem by constructing a protocol for secure computation with
    firewalls that has two main advantages over the original protocol from Eurocrypt
    2015. Firstly, it is a multiparty computation protocol (i.e. it works for an arbitrary
    number n of the parties, and not just for 2). Secondly, it is secure in much stronger
    corruption settings, namely in the active corruption model. More precisely: we
    consider an adversary that can fully corrupt up to \U0001D45B−1 parties, while
    the remaining parties are corrupt in a functionality-preserving way.\r\nOur core
    techniques are: malleable commitments and malleable non-interactive zero-knowledge,
    which in particular allow us to create a novel protocol for multiparty augmented
    coin-tossing into the well with reverse firewalls (that is based on a protocol
    of Lindell from Crypto 2001)."
acknowledgement: We would like to thank the anonymous reviewers for their helpful
  comments and suggestions. The work was initiated while the first author was in IIT
  Madras, India. Part of this work was done while the author was visiting the University
  of Warsaw. This project has received funding from the European Research Council
  (ERC) under the European Union’s Horizon 2020 research and innovation programme
  (682815 - TOCNeT) and from the Foundation for Polish Science under grant TEAM/2016-1/4
  founded within the UE 2014–2020 Smart Growth Operational Program. The last author
  was supported by the Independent Research Fund Denmark project BETHE and the Concordium
  Blockchain Research Center, Aarhus University, Denmark.
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Suvradip
  full_name: Chakraborty, Suvradip
  id: B9CD0494-D033-11E9-B219-A439E6697425
  last_name: Chakraborty
- first_name: Stefan
  full_name: Dziembowski, Stefan
  last_name: Dziembowski
- first_name: Jesper Buus
  full_name: Nielsen, Jesper Buus
  last_name: Nielsen
citation:
  ama: 'Chakraborty S, Dziembowski S, Nielsen JB. Reverse firewalls for actively secure MPCs.
    In: <i>Advances in Cryptology – CRYPTO 2020</i>. Vol 12171. Springer Nature; 2020:732-762.
    doi:<a href="https://doi.org/10.1007/978-3-030-56880-1_26">10.1007/978-3-030-56880-1_26</a>'
  apa: 'Chakraborty, S., Dziembowski, S., &#38; Nielsen, J. B. (2020). Reverse firewalls for actively secure MPCs.
    In <i>Advances in Cryptology – CRYPTO 2020</i> (Vol. 12171, pp. 732–762). Santa
    Barbara, CA, United States: Springer Nature. <a href="https://doi.org/10.1007/978-3-030-56880-1_26">https://doi.org/10.1007/978-3-030-56880-1_26</a>'
  chicago: Chakraborty, Suvradip, Stefan Dziembowski, and Jesper Buus Nielsen. “Reverse Firewalls for Actively Secure MPCs.”
    In <i>Advances in Cryptology – CRYPTO 2020</i>, 12171:732–62. Springer Nature,
    2020. <a href="https://doi.org/10.1007/978-3-030-56880-1_26">https://doi.org/10.1007/978-3-030-56880-1_26</a>.
  ieee: S. Chakraborty, S. Dziembowski, and J. B. Nielsen, “Reverse firewalls for actively secure MPCs,”
    in <i>Advances in Cryptology – CRYPTO 2020</i>, Santa Barbara, CA, United States,
    2020, vol. 12171, pp. 732–762.
  ista: 'Chakraborty S, Dziembowski S, Nielsen JB. 2020. Reverse firewalls for actively secure MPCs.
    Advances in Cryptology – CRYPTO 2020. CRYPTO: Annual International Cryptology
    Conference, LNCS, vol. 12171, 732–762.'
  mla: Chakraborty, Suvradip, et al. “Reverse Firewalls for Actively Secure MPCs.”
    <i>Advances in Cryptology – CRYPTO 2020</i>, vol. 12171, Springer Nature, 2020,
    pp. 732–62, doi:<a href="https://doi.org/10.1007/978-3-030-56880-1_26">10.1007/978-3-030-56880-1_26</a>.
  short: S. Chakraborty, S. Dziembowski, J.B. Nielsen, in:, Advances in Cryptology
    – CRYPTO 2020, Springer Nature, 2020, pp. 732–762.
conference:
  end_date: 2020-08-21
  location: Santa Barbara, CA, United States
  name: 'CRYPTO: Annual International Cryptology Conference'
  start_date: 2020-08-17
date_created: 2020-08-30T22:01:12Z
date_published: 2020-08-10T00:00:00Z
date_updated: 2021-01-12T08:18:08Z
day: '10'
department:
- _id: KrPi
doi: 10.1007/978-3-030-56880-1_26
ec_funded: 1
intvolume: '     12171'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2019/1317
month: '08'
oa: 1
oa_version: Preprint
page: 732-762
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '682815'
  name: Teaching Old Crypto New Tricks
publication: Advances in Cryptology – CRYPTO 2020
publication_identifier:
  eissn:
  - '16113349'
  isbn:
  - '9783030568795'
  issn:
  - '03029743'
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Reverse firewalls for actively secure MPCs
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 12171
year: '2020'
...