---
_id: '10076'
abstract:
- lang: eng
  text: We present a novel approach for blockchain asset owners to reclaim their funds
    in case of accidental private-key loss or transfer to a mistyped address. Our
    solution can be deployed upon failure or absence of proactively implemented backup
    mechanisms, such as secret sharing and cold storage. The main advantages against
    previous proposals is it does not require any prior action from users and works
    with both single-key and multi-sig accounts. We achieve this by a 3-phase   Commit()→Reveal()→Claim()−or−Challenge()  smart
    contract that enables accessing funds of addresses for which the spending key
    is not available. We provide an analysis of the threat and incentive models and
    formalize the concept of reactive KEy-Loss Protection (KELP).
acknowledgement: The authors would like to thank all anonymous reviewers of FC21 WTSC
  workshop for comments and suggestions that greatly improved the quality of this
  paper.
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Sam
  full_name: Blackshear, Sam
  last_name: Blackshear
- first_name: Konstantinos
  full_name: Chalkias, Konstantinos
  last_name: Chalkias
- first_name: Panagiotis
  full_name: Chatzigiannis, Panagiotis
  last_name: Chatzigiannis
- first_name: Riyaz
  full_name: Faizullabhoy, Riyaz
  last_name: Faizullabhoy
- first_name: Irakliy
  full_name: Khaburzaniya, Irakliy
  last_name: Khaburzaniya
- first_name: Eleftherios
  full_name: Kokoris Kogias, Eleftherios
  id: f5983044-d7ef-11ea-ac6d-fd1430a26d30
  last_name: Kokoris Kogias
- first_name: Joshua
  full_name: Lind, Joshua
  last_name: Lind
- first_name: David
  full_name: Wong, David
  last_name: Wong
- first_name: Tim
  full_name: Zakian, Tim
  last_name: Zakian
citation:
  ama: 'Blackshear S, Chalkias K, Chatzigiannis P, et al. Reactive key-loss protection
    in blockchains. In: <i>FC 2021 Workshops</i>. Vol 12676. Springer Nature; 2021:431-450.
    doi:<a href="https://doi.org/10.1007/978-3-662-63958-0_34">10.1007/978-3-662-63958-0_34</a>'
  apa: 'Blackshear, S., Chalkias, K., Chatzigiannis, P., Faizullabhoy, R., Khaburzaniya,
    I., Kokoris Kogias, E., … Zakian, T. (2021). Reactive key-loss protection in blockchains.
    In <i>FC 2021 Workshops</i> (Vol. 12676, pp. 431–450). Virtual: Springer Nature.
    <a href="https://doi.org/10.1007/978-3-662-63958-0_34">https://doi.org/10.1007/978-3-662-63958-0_34</a>'
  chicago: Blackshear, Sam, Konstantinos Chalkias, Panagiotis Chatzigiannis, Riyaz
    Faizullabhoy, Irakliy Khaburzaniya, Eleftherios Kokoris Kogias, Joshua Lind, David
    Wong, and Tim Zakian. “Reactive Key-Loss Protection in Blockchains.” In <i>FC
    2021 Workshops</i>, 12676:431–50. Springer Nature, 2021. <a href="https://doi.org/10.1007/978-3-662-63958-0_34">https://doi.org/10.1007/978-3-662-63958-0_34</a>.
  ieee: S. Blackshear <i>et al.</i>, “Reactive key-loss protection in blockchains,”
    in <i>FC 2021 Workshops</i>, Virtual, 2021, vol. 12676, pp. 431–450.
  ista: 'Blackshear S, Chalkias K, Chatzigiannis P, Faizullabhoy R, Khaburzaniya I,
    Kokoris Kogias E, Lind J, Wong D, Zakian T. 2021. Reactive key-loss protection
    in blockchains. FC 2021 Workshops. FC: International Conference on Financial Cryptography
    and Data Security, LNCS, vol. 12676, 431–450.'
  mla: Blackshear, Sam, et al. “Reactive Key-Loss Protection in Blockchains.” <i>FC
    2021 Workshops</i>, vol. 12676, Springer Nature, 2021, pp. 431–50, doi:<a href="https://doi.org/10.1007/978-3-662-63958-0_34">10.1007/978-3-662-63958-0_34</a>.
  short: S. Blackshear, K. Chalkias, P. Chatzigiannis, R. Faizullabhoy, I. Khaburzaniya,
    E. Kokoris Kogias, J. Lind, D. Wong, T. Zakian, in:, FC 2021 Workshops, Springer
    Nature, 2021, pp. 431–450.
conference:
  end_date: 2021-03-05
  location: Virtual
  name: 'FC: International Conference on Financial Cryptography and Data Security'
  start_date: 2021-03-01
date_created: 2021-10-03T22:01:24Z
date_published: 2021-09-17T00:00:00Z
date_updated: 2023-08-14T07:06:16Z
day: '17'
department:
- _id: ElKo
doi: 10.1007/978-3-662-63958-0_34
external_id:
  isi:
  - '000713005000034'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://research.fb.com/publications/reactive-key-loss-protection-in-blockchains/
month: '09'
oa: 1
oa_version: Preprint
page: 431-450
publication: FC 2021 Workshops
publication_identifier:
  eisbn:
  - 978-3-662-63958-0
  eissn:
  - 1611-3349
  isbn:
  - 978-3-6626-3957-3
  issn:
  - 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Reactive key-loss protection in blockchains
type: conference
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: '12676 '
year: '2021'
...