---
_id: '10407'
abstract:
- lang: eng
  text: Digital hardware Trojans are integrated circuits whose implementation differ
    from the specification in an arbitrary and malicious way. For example, the circuit
    can differ from its specified input/output behavior after some fixed number of
    queries (known as “time bombs”) or on some particular input (known as “cheat codes”).
    To detect such Trojans, countermeasures using multiparty computation (MPC) or
    verifiable computation (VC) have been proposed. On a high level, to realize a
    circuit with specification   F  one has more sophisticated circuits   F⋄  manufactured
    (where   F⋄  specifies a MPC or VC of   F ), and then embeds these   F⋄ ’s into
    a master circuit which must be trusted but is relatively simple compared to   F
    . Those solutions impose a significant overhead as   F⋄  is much more complex
    than   F , also the master circuits are not exactly trivial. In this work, we
    show that in restricted settings, where   F  has no evolving state and is queried
    on independent inputs, we can achieve a relaxed security notion using very simple
    constructions. In particular, we do not change the specification of the circuit
    at all (i.e.,   F=F⋄ ). Moreover the master circuit basically just queries a subset
    of its manufactured circuits and checks if they’re all the same. The security
    we achieve guarantees that, if the manufactured circuits are initially tested
    on up to T inputs, the master circuit will catch Trojans that try to deviate on
    significantly more than a 1/T fraction of the inputs. This bound is optimal for
    the type of construction considered, and we provably achieve it using a construction
    where 12 instantiations of   F  need to be embedded into the master. We also discuss
    an extremely simple construction with just 2 instantiations for which we conjecture
    that it already achieves the optimal bound.
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: Małgorzata
  full_name: Gałązka, Małgorzata
  last_name: Gałązka
- first_name: Tomasz
  full_name: Lizurej, Tomasz
  last_name: Lizurej
- first_name: Krzysztof Z
  full_name: Pietrzak, Krzysztof Z
  id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
  last_name: Pietrzak
  orcid: 0000-0002-9139-1654
- first_name: Michelle X
  full_name: Yeo, Michelle X
  id: 2D82B818-F248-11E8-B48F-1D18A9856A87
  last_name: Yeo
citation:
  ama: 'Chakraborty S, Dziembowski S, Gałązka M, Lizurej T, Pietrzak KZ, Yeo MX. Trojan-resilience
    without cryptography. In: Vol 13043. Springer Nature; 2021:397-428. doi:<a href="https://doi.org/10.1007/978-3-030-90453-1_14">10.1007/978-3-030-90453-1_14</a>'
  apa: 'Chakraborty, S., Dziembowski, S., Gałązka, M., Lizurej, T., Pietrzak, K. Z.,
    &#38; Yeo, M. X. (2021). Trojan-resilience without cryptography (Vol. 13043, pp.
    397–428). Presented at the TCC: Theory of Cryptography Conference, Raleigh, NC,
    United States: Springer Nature. <a href="https://doi.org/10.1007/978-3-030-90453-1_14">https://doi.org/10.1007/978-3-030-90453-1_14</a>'
  chicago: Chakraborty, Suvradip, Stefan Dziembowski, Małgorzata Gałązka, Tomasz Lizurej,
    Krzysztof Z Pietrzak, and Michelle X Yeo. “Trojan-Resilience without Cryptography,”
    13043:397–428. Springer Nature, 2021. <a href="https://doi.org/10.1007/978-3-030-90453-1_14">https://doi.org/10.1007/978-3-030-90453-1_14</a>.
  ieee: 'S. Chakraborty, S. Dziembowski, M. Gałązka, T. Lizurej, K. Z. Pietrzak, and
    M. X. Yeo, “Trojan-resilience without cryptography,” presented at the TCC: Theory
    of Cryptography Conference, Raleigh, NC, United States, 2021, vol. 13043, pp.
    397–428.'
  ista: 'Chakraborty S, Dziembowski S, Gałązka M, Lizurej T, Pietrzak KZ, Yeo MX.
    2021. Trojan-resilience without cryptography. TCC: Theory of Cryptography Conference,
    LNCS, vol. 13043, 397–428.'
  mla: Chakraborty, Suvradip, et al. <i>Trojan-Resilience without Cryptography</i>.
    Vol. 13043, Springer Nature, 2021, pp. 397–428, doi:<a href="https://doi.org/10.1007/978-3-030-90453-1_14">10.1007/978-3-030-90453-1_14</a>.
  short: S. Chakraborty, S. Dziembowski, M. Gałązka, T. Lizurej, K.Z. Pietrzak, M.X.
    Yeo, in:, Springer Nature, 2021, pp. 397–428.
conference:
  end_date: 2021-11-11
  location: Raleigh, NC, United States
  name: 'TCC: Theory of Cryptography Conference'
  start_date: 2021-11-08
date_created: 2021-12-05T23:01:42Z
date_published: 2021-11-04T00:00:00Z
date_updated: 2023-08-14T13:07:46Z
day: '04'
department:
- _id: KrPi
doi: 10.1007/978-3-030-90453-1_14
ec_funded: 1
external_id:
  isi:
  - '000728364000014'
intvolume: '     13043'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2021/1224
month: '11'
oa: 1
oa_version: Preprint
page: 397-428
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '682815'
  name: Teaching Old Crypto New Tricks
publication_identifier:
  eissn:
  - 1611-3349
  isbn:
  - 9-783-0309-0452-4
  issn:
  - 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Trojan-resilience without cryptography
type: conference
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 13043
year: '2021'
...
---
_id: '10609'
abstract:
- lang: eng
  text: "We study Multi-party computation (MPC) in the setting of subversion, where
    the adversary tampers with the machines of honest parties. Our goal is to construct
    actively secure MPC protocols where parties are corrupted adaptively by an adversary
    (as in the standard adaptive security setting), and in addition, honest parties’
    machines are compromised.\r\nThe idea of reverse firewalls (RF) was introduced
    at EUROCRYPT’15 by Mironov and Stephens-Davidowitz as an approach to protecting
    protocols against corruption of honest parties’ devices. Intuitively, an RF for
    a party   P  is an external entity that sits between   P  and the outside world
    and whose scope is to sanitize   P ’s incoming and outgoing messages in the face
    of subversion of their computer. Mironov and Stephens-Davidowitz constructed a
    protocol for passively-secure two-party computation. At CRYPTO’20, Chakraborty,
    Dziembowski and Nielsen constructed a protocol for secure computation with firewalls
    that improved on this result, both by extending it to multi-party computation
    protocol, and considering active security in the presence of static corruptions.
    In this paper, we initiate the study of RF for MPC in the adaptive setting. We
    put forward a definition for adaptively secure MPC in the reverse firewall setting,
    explore relationships among the security notions, and then construct reverse firewalls
    for MPC in this stronger setting of adaptive security. We also resolve the open
    question of Chakraborty, Dziembowski and Nielsen by removing the need for a trusted
    setup in constructing RF for MPC. Towards this end, we construct reverse firewalls
    for adaptively secure augmented coin tossing and adaptively secure zero-knowledge
    protocols and obtain a constant round adaptively secure MPC protocol in the reverse
    firewall setting without setup. Along the way, we propose a new multi-party adaptively
    secure coin tossing protocol in the plain model, that is of independent interest."
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: Chaya
  full_name: Ganesh, Chaya
  last_name: Ganesh
- first_name: Mahak
  full_name: Pancholi, Mahak
  last_name: Pancholi
- first_name: Pratik
  full_name: Sarkar, Pratik
  last_name: Sarkar
citation:
  ama: 'Chakraborty S, Ganesh C, Pancholi M, Sarkar P. Reverse firewalls for adaptively
    secure MPC without setup. In: <i>27th International Conference on the Theory and
    Application of Cryptology and Information Security</i>. Vol 13091. Springer Nature;
    2021:335-364. doi:<a href="https://doi.org/10.1007/978-3-030-92075-3_12">10.1007/978-3-030-92075-3_12</a>'
  apa: 'Chakraborty, S., Ganesh, C., Pancholi, M., &#38; Sarkar, P. (2021). Reverse
    firewalls for adaptively secure MPC without setup. In <i>27th International Conference
    on the Theory and Application of Cryptology and Information Security</i> (Vol.
    13091, pp. 335–364). Virtual, Singapore: Springer Nature. <a href="https://doi.org/10.1007/978-3-030-92075-3_12">https://doi.org/10.1007/978-3-030-92075-3_12</a>'
  chicago: Chakraborty, Suvradip, Chaya Ganesh, Mahak Pancholi, and Pratik Sarkar.
    “Reverse Firewalls for Adaptively Secure MPC without Setup.” In <i>27th International
    Conference on the Theory and Application of Cryptology and Information Security</i>,
    13091:335–64. Springer Nature, 2021. <a href="https://doi.org/10.1007/978-3-030-92075-3_12">https://doi.org/10.1007/978-3-030-92075-3_12</a>.
  ieee: S. Chakraborty, C. Ganesh, M. Pancholi, and P. Sarkar, “Reverse firewalls
    for adaptively secure MPC without setup,” in <i>27th International Conference
    on the Theory and Application of Cryptology and Information Security</i>, Virtual,
    Singapore, 2021, vol. 13091, pp. 335–364.
  ista: 'Chakraborty S, Ganesh C, Pancholi M, Sarkar P. 2021. Reverse firewalls for
    adaptively secure MPC without setup. 27th International Conference on the Theory
    and Application of Cryptology and Information Security. ASIACRYPT: International
    Conference on Cryptology in Asia, LNCS, vol. 13091, 335–364.'
  mla: Chakraborty, Suvradip, et al. “Reverse Firewalls for Adaptively Secure MPC
    without Setup.” <i>27th International Conference on the Theory and Application
    of Cryptology and Information Security</i>, vol. 13091, Springer Nature, 2021,
    pp. 335–64, doi:<a href="https://doi.org/10.1007/978-3-030-92075-3_12">10.1007/978-3-030-92075-3_12</a>.
  short: S. Chakraborty, C. Ganesh, M. Pancholi, P. Sarkar, in:, 27th International
    Conference on the Theory and Application of Cryptology and Information Security,
    Springer Nature, 2021, pp. 335–364.
conference:
  end_date: 2021-12-10
  location: Virtual, Singapore
  name: 'ASIACRYPT: International Conference on Cryptology in Asia'
  start_date: 2021-12-06
date_created: 2022-01-09T23:01:27Z
date_published: 2021-12-01T00:00:00Z
date_updated: 2023-08-17T06:34:41Z
day: '01'
department:
- _id: KrPi
doi: 10.1007/978-3-030-92075-3_12
ec_funded: 1
external_id:
  isi:
  - '000927876200012'
intvolume: '     13091'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2021/1262
month: '12'
oa: 1
oa_version: Preprint
page: 335-364
project:
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '682815'
  name: Teaching Old Crypto New Tricks
publication: 27th International Conference on the Theory and Application of Cryptology
  and Information Security
publication_identifier:
  eisbn:
  - 978-3-030-92075-3
  eissn:
  - 1611-3349
  isbn:
  - 978-3-030-92074-6
  issn:
  - 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Reverse firewalls for adaptively secure MPC without setup
type: conference
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 13091
year: '2021'
...
---
_id: '9826'
abstract:
- lang: eng
  text: "Automated contract tracing aims at supporting manual contact tracing during
    pandemics by alerting users of encounters with infected people. There are currently
    many proposals for protocols (like the “decentralized” DP-3T and PACT or the “centralized”
    ROBERT and DESIRE) to be run on mobile phones, where the basic idea is to regularly
    broadcast (using low energy Bluetooth) some values, and at the same time store
    (a function of) incoming messages broadcasted by users in their proximity. In
    the existing proposals one can trigger false positives on a massive scale by an
    “inverse-Sybil” attack, where a large number of devices (malicious users or hacked
    phones) pretend to be the same user, such that later, just a single person needs
    to be diagnosed (and allowed to upload) to trigger an alert for all users who
    were in proximity to any of this large group of devices.\r\n\r\nWe propose the
    first protocols that do not succumb to such attacks assuming the devices involved
    in the attack do not constantly communicate, which we observe is a necessary assumption.
    The high level idea of the protocols is to derive the values to be broadcasted
    by a hash chain, so that two (or more) devices who want to launch an inverse-Sybil
    attack will not be able to connect their respective chains and thus only one of
    them will be able to upload. Our protocols also achieve security against replay,
    belated replay, and one of them even against relay attacks."
acknowledgement: Guillermo Pascual-Perez and Michelle Yeo were funded by the European
  Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska–Curie
  Grant Agreement No. 665385; the remaining contributors to this project have received
  funding from the European Research Council (ERC) under the European Union’s Horizon
  2020 research and innovation programme (682815 - TOCNeT).
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Benedikt
  full_name: Auerbach, Benedikt
  id: D33D2B18-E445-11E9-ABB7-15F4E5697425
  last_name: Auerbach
  orcid: 0000-0002-7553-6606
- first_name: Suvradip
  full_name: Chakraborty, Suvradip
  id: B9CD0494-D033-11E9-B219-A439E6697425
  last_name: Chakraborty
- first_name: Karen
  full_name: Klein, Karen
  id: 3E83A2F8-F248-11E8-B48F-1D18A9856A87
  last_name: Klein
- first_name: Guillermo
  full_name: Pascual Perez, Guillermo
  id: 2D7ABD02-F248-11E8-B48F-1D18A9856A87
  last_name: Pascual Perez
- first_name: Krzysztof Z
  full_name: Pietrzak, Krzysztof Z
  id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
  last_name: Pietrzak
  orcid: 0000-0002-9139-1654
- first_name: Michael
  full_name: Walter, Michael
  id: 488F98B0-F248-11E8-B48F-1D18A9856A87
  last_name: Walter
  orcid: 0000-0003-3186-2482
- first_name: Michelle X
  full_name: Yeo, Michelle X
  id: 2D82B818-F248-11E8-B48F-1D18A9856A87
  last_name: Yeo
citation:
  ama: 'Auerbach B, Chakraborty S, Klein K, et al. Inverse-Sybil attacks in automated
    contact tracing. In: <i>Topics in Cryptology – CT-RSA 2021</i>. Vol 12704. Springer
    Nature; 2021:399-421. doi:<a href="https://doi.org/10.1007/978-3-030-75539-3_17">10.1007/978-3-030-75539-3_17</a>'
  apa: 'Auerbach, B., Chakraborty, S., Klein, K., Pascual Perez, G., Pietrzak, K.
    Z., Walter, M., &#38; Yeo, M. X. (2021). Inverse-Sybil attacks in automated contact
    tracing. In <i>Topics in Cryptology – CT-RSA 2021</i> (Vol. 12704, pp. 399–421).
    Virtual Event: Springer Nature. <a href="https://doi.org/10.1007/978-3-030-75539-3_17">https://doi.org/10.1007/978-3-030-75539-3_17</a>'
  chicago: Auerbach, Benedikt, Suvradip Chakraborty, Karen Klein, Guillermo Pascual
    Perez, Krzysztof Z Pietrzak, Michael Walter, and Michelle X Yeo. “Inverse-Sybil
    Attacks in Automated Contact Tracing.” In <i>Topics in Cryptology – CT-RSA 2021</i>,
    12704:399–421. Springer Nature, 2021. <a href="https://doi.org/10.1007/978-3-030-75539-3_17">https://doi.org/10.1007/978-3-030-75539-3_17</a>.
  ieee: B. Auerbach <i>et al.</i>, “Inverse-Sybil attacks in automated contact tracing,”
    in <i>Topics in Cryptology – CT-RSA 2021</i>, Virtual Event, 2021, vol. 12704,
    pp. 399–421.
  ista: 'Auerbach B, Chakraborty S, Klein K, Pascual Perez G, Pietrzak KZ, Walter
    M, Yeo MX. 2021. Inverse-Sybil attacks in automated contact tracing. Topics in
    Cryptology – CT-RSA 2021. CT-RSA: Cryptographers’ Track at the RSA Conference,
    LNCS, vol. 12704, 399–421.'
  mla: Auerbach, Benedikt, et al. “Inverse-Sybil Attacks in Automated Contact Tracing.”
    <i>Topics in Cryptology – CT-RSA 2021</i>, vol. 12704, Springer Nature, 2021,
    pp. 399–421, doi:<a href="https://doi.org/10.1007/978-3-030-75539-3_17">10.1007/978-3-030-75539-3_17</a>.
  short: B. Auerbach, S. Chakraborty, K. Klein, G. Pascual Perez, K.Z. Pietrzak, M.
    Walter, M.X. Yeo, in:, Topics in Cryptology – CT-RSA 2021, Springer Nature, 2021,
    pp. 399–421.
conference:
  end_date: 2021-05-20
  location: Virtual Event
  name: 'CT-RSA: Cryptographers’ Track at the RSA Conference'
  start_date: 2021-05-17
date_created: 2021-08-08T22:01:30Z
date_published: 2021-05-11T00:00:00Z
date_updated: 2023-02-23T14:09:56Z
day: '11'
department:
- _id: KrPi
- _id: GradSch
doi: 10.1007/978-3-030-75539-3_17
ec_funded: 1
intvolume: '     12704'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2020/670
month: '05'
oa: 1
oa_version: Submitted Version
page: 399-421
project:
- _id: 2564DBCA-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '665385'
  name: International IST Doctoral Program
- _id: 258AA5B2-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '682815'
  name: Teaching Old Crypto New Tricks
publication: Topics in Cryptology – CT-RSA 2021
publication_identifier:
  eissn:
  - '16113349'
  isbn:
  - '9783030755386'
  issn:
  - '03029743'
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Inverse-Sybil attacks in automated contact tracing
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 12704
year: '2021'
...
---
_id: '10865'
abstract:
- lang: eng
  text: "We introduce the notion of Witness Maps as a cryptographic notion of a proof
    system. A Unique Witness Map (UWM) deterministically maps all witnesses for an
    \  NP  statement to a single representative witness, resulting in a computationally
    sound, deterministic-prover, non-interactive witness independent proof system.
    A relaxation of UWM, called Compact Witness Map (CWM), maps all the witnesses
    to a small number of witnesses, resulting in a “lossy” deterministic-prover, non-interactive
    proof-system. We also define a Dual Mode Witness Map (DMWM) which adds an “extractable”
    mode to a CWM.\r\nOur main construction is a DMWM for all   NP  relations, assuming
    sub-exponentially secure indistinguishability obfuscation (  iO ), along with
    standard cryptographic assumptions. The DMWM construction relies on a CWM and
    a new primitive called Cumulative All-Lossy-But-One Trapdoor Functions (C-ALBO-TDF),
    both of which are in turn instantiated based on   iO  and other primitives. Our
    instantiation of a CWM is in fact a UWM; in turn, we show that a UWM implies Witness
    Encryption. Along the way to constructing UWM and C-ALBO-TDF, we also construct,
    from standard assumptions, Puncturable Digital Signatures and a new primitive
    called Cumulative Lossy Trapdoor Functions (C-LTDF). The former improves up on
    a construction of Bellare et al. (Eurocrypt 2016), who relied on sub-exponentially
    secure   iO  and sub-exponentially secure OWF.\r\nAs an application of our constructions,
    we show how to use a DMWM to construct the first leakage and tamper-resilient
    signatures with a deterministic signer, thereby solving a decade old open problem
    posed by Katz and Vaikunthanathan (Asiacrypt 2009), by Boyle, Segev and Wichs
    (Eurocrypt 2011), as well as by Faonio and Venturi (Asiacrypt 2016). Our construction
    achieves the optimal leakage rate of   1−o(1) ."
acknowledgement: We would like to thank the anonymous reviewers of PKC 2019 for their
  useful comments and suggestions. We thank Omer Paneth for pointing out to us the
  connection between Unique Witness Maps (UWM) and Witness encryption (WE). The first
  author would like to acknowledge Pandu Rangan for his involvement during the initial
  discussion phase of the project.
article_processing_charge: No
author:
- first_name: Suvradip
  full_name: Chakraborty, Suvradip
  id: B9CD0494-D033-11E9-B219-A439E6697425
  last_name: Chakraborty
- first_name: Manoj
  full_name: Prabhakaran, Manoj
  last_name: Prabhakaran
- first_name: Daniel
  full_name: Wichs, Daniel
  last_name: Wichs
citation:
  ama: 'Chakraborty S, Prabhakaran M, Wichs D. Witness maps and applications. In:
    Kiayias A, ed. <i>Public-Key Cryptography</i>. Vol 12110. LNCS. Cham: Springer
    Nature; 2020:220-246. doi:<a href="https://doi.org/10.1007/978-3-030-45374-9_8">10.1007/978-3-030-45374-9_8</a>'
  apa: 'Chakraborty, S., Prabhakaran, M., &#38; Wichs, D. (2020). Witness maps and
    applications. In A. Kiayias (Ed.), <i>Public-Key Cryptography</i> (Vol. 12110,
    pp. 220–246). Cham: Springer Nature. <a href="https://doi.org/10.1007/978-3-030-45374-9_8">https://doi.org/10.1007/978-3-030-45374-9_8</a>'
  chicago: 'Chakraborty, Suvradip, Manoj Prabhakaran, and Daniel Wichs. “Witness Maps
    and Applications.” In <i>Public-Key Cryptography</i>, edited by A Kiayias, 12110:220–46.
    LNCS. Cham: Springer Nature, 2020. <a href="https://doi.org/10.1007/978-3-030-45374-9_8">https://doi.org/10.1007/978-3-030-45374-9_8</a>.'
  ieee: 'S. Chakraborty, M. Prabhakaran, and D. Wichs, “Witness maps and applications,”
    in <i>Public-Key Cryptography</i>, vol. 12110, A. Kiayias, Ed. Cham: Springer
    Nature, 2020, pp. 220–246.'
  ista: 'Chakraborty S, Prabhakaran M, Wichs D. 2020.Witness maps and applications.
    In: Public-Key Cryptography. vol. 12110, 220–246.'
  mla: Chakraborty, Suvradip, et al. “Witness Maps and Applications.” <i>Public-Key
    Cryptography</i>, edited by A Kiayias, vol. 12110, Springer Nature, 2020, pp.
    220–46, doi:<a href="https://doi.org/10.1007/978-3-030-45374-9_8">10.1007/978-3-030-45374-9_8</a>.
  short: S. Chakraborty, M. Prabhakaran, D. Wichs, in:, A. Kiayias (Ed.), Public-Key
    Cryptography, Springer Nature, Cham, 2020, pp. 220–246.
date_created: 2022-03-18T11:35:51Z
date_published: 2020-04-29T00:00:00Z
date_updated: 2023-09-05T15:10:02Z
day: '29'
doi: 10.1007/978-3-030-45374-9_8
editor:
- first_name: A
  full_name: Kiayias, A
  last_name: Kiayias
intvolume: '     12110'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2020/090
month: '04'
oa: 1
oa_version: Preprint
page: 220-246
place: Cham
publication: Public-Key Cryptography
publication_identifier:
  eissn:
  - 1611-3349
  isbn:
  - '9783030453732'
  - '9783030453749'
  issn:
  - 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
series_title: LNCS
status: public
title: Witness maps and applications
type: book_chapter
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 12110
year: '2020'
...
---
_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'
...
