---
_id: '14989'
abstract:
- lang: eng
  text: "Encryption alone is not enough for secure end-to end encrypted messaging:
    a server must also honestly serve public keys to users. Key transparency has been
    presented as an efficient\r\nsolution for detecting (and hence deterring) a server
    that attempts to dishonestly serve keys. Key transparency involves two major components:
    (1) a username to public key mapping, stored and cryptographically committed to
    by the server, and, (2) an outof-band consistency protocol for serving short commitments
    to users. In the setting of real-world deployments and supporting production scale,
    new challenges must be considered for both of these components. We enumerate these
    challenges and provide solutions to address them. In particular, we design and
    implement a memory-optimized and privacy-preserving verifiable data structure
    for committing to the username to public key store.\r\nTo make this implementation
    viable for production, we also integrate support for persistent and distributed
    storage. We also propose a future-facing solution, termed “compaction”, as\r\na
    mechanism for mitigating practical issues that arise from dealing with infinitely
    growing server data structures. Finally, we implement a consensusless solution
    that achieves the minimum requirements for a service that consistently distributes
    commitments for a transparency application, providing a much more efficient protocol
    for distributing small and consistent\r\ncommitments to users. This culminates
    in our production-grade implementation of a key transparency system (Parakeet)
    which we have open-sourced, along with a demonstration of feasibility through
    our benchmarks."
acknowledgement: This work is supported by the Novi team at Meta and funded in part
  by IC3 industry partners and NSF grant 1943499.
article_processing_charge: No
author:
- first_name: Harjasleen
  full_name: Malvai, Harjasleen
  last_name: Malvai
- first_name: Eleftherios
  full_name: Kokoris Kogias, Eleftherios
  id: f5983044-d7ef-11ea-ac6d-fd1430a26d30
  last_name: Kokoris Kogias
- first_name: Alberto
  full_name: Sonnino, Alberto
  last_name: Sonnino
- first_name: Esha
  full_name: Ghosh, Esha
  last_name: Ghosh
- first_name: Ercan
  full_name: Oztürk, Ercan
  last_name: Oztürk
- first_name: Kevin
  full_name: Lewi, Kevin
  last_name: Lewi
- first_name: Sean
  full_name: Lawlor, Sean
  last_name: Lawlor
citation:
  ama: 'Malvai H, Kokoris Kogias E, Sonnino A, et al. Parakeet: Practical key transparency
    for end-to-end eEncrypted messaging. In: <i>Proceedings of the 2023 Network and
    Distributed System Security Symposium</i>. Internet Society; 2023. doi:<a href="https://doi.org/10.14722/ndss.2023.24545">10.14722/ndss.2023.24545</a>'
  apa: 'Malvai, H., Kokoris Kogias, E., Sonnino, A., Ghosh, E., Oztürk, E., Lewi,
    K., &#38; Lawlor, S. (2023). Parakeet: Practical key transparency for end-to-end
    eEncrypted messaging. In <i>Proceedings of the 2023 Network and Distributed System
    Security Symposium</i>. San Diego, CA, United States: Internet Society. <a href="https://doi.org/10.14722/ndss.2023.24545">https://doi.org/10.14722/ndss.2023.24545</a>'
  chicago: 'Malvai, Harjasleen, Eleftherios Kokoris Kogias, Alberto Sonnino, Esha
    Ghosh, Ercan Oztürk, Kevin Lewi, and Sean Lawlor. “Parakeet: Practical Key Transparency
    for End-to-End EEncrypted Messaging.” In <i>Proceedings of the 2023 Network and
    Distributed System Security Symposium</i>. Internet Society, 2023. <a href="https://doi.org/10.14722/ndss.2023.24545">https://doi.org/10.14722/ndss.2023.24545</a>.'
  ieee: 'H. Malvai <i>et al.</i>, “Parakeet: Practical key transparency for end-to-end
    eEncrypted messaging,” in <i>Proceedings of the 2023 Network and Distributed System
    Security Symposium</i>, San Diego, CA, United States, 2023.'
  ista: 'Malvai H, Kokoris Kogias E, Sonnino A, Ghosh E, Oztürk E, Lewi K, Lawlor
    S. 2023. Parakeet: Practical key transparency for end-to-end eEncrypted messaging.
    Proceedings of the 2023 Network and Distributed System Security Symposium. NDSS:
    Network and Distributed Systems Security.'
  mla: 'Malvai, Harjasleen, et al. “Parakeet: Practical Key Transparency for End-to-End
    EEncrypted Messaging.” <i>Proceedings of the 2023 Network and Distributed System
    Security Symposium</i>, Internet Society, 2023, doi:<a href="https://doi.org/10.14722/ndss.2023.24545">10.14722/ndss.2023.24545</a>.'
  short: H. Malvai, E. Kokoris Kogias, A. Sonnino, E. Ghosh, E. Oztürk, K. Lewi, S.
    Lawlor, in:, Proceedings of the 2023 Network and Distributed System Security Symposium,
    Internet Society, 2023.
conference:
  end_date: 2023-03-03
  location: San Diego, CA, United States
  name: 'NDSS: Network and Distributed Systems Security'
  start_date: 2023-02-27
date_created: 2024-02-14T14:20:40Z
date_published: 2023-03-01T00:00:00Z
date_updated: 2024-02-19T12:11:15Z
day: '01'
department:
- _id: ElKo
doi: 10.14722/ndss.2023.24545
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2023/081
month: '03'
oa: 1
oa_version: Published Version
publication: Proceedings of the 2023 Network and Distributed System Security Symposium
publication_identifier:
  isbn:
  - '1891562835'
publication_status: published
publisher: Internet Society
quality_controlled: '1'
status: public
title: 'Parakeet: Practical key transparency for end-to-end eEncrypted messaging'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2023'
...