Quotable Signatures for Authenticating Shared Quotes

Joan Boyar, Simon Erfurth, Kim S. Larsen*, Ruben Niederhagen

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

Abstract

Quotable signature schemes are digital signature schemes with the additional property that from the signature for a message, any party can extract signatures for (allowable) quotes from the message, without knowing the secret key or interacting with the signer of the original message. Crucially, the extracted signatures are still signed with the original secret key. We define a notion of security for quotable signature schemes and construct a concrete example of a quotable signature scheme, using Merkle trees and classical digital signature schemes. The scheme is shown to be secure, with respect to the aforementioned notion of security. Additionally, we prove bounds on the complexity of the constructed scheme. Finally, concrete use cases of quotable signatures are considered, using them to combat misinformation by bolstering authentic content on social media. We consider both how quotable signatures can be used, and why using them could help mitigate the effects of fake news.
Original languageEnglish
Title of host publicationProgress in Cryptology – LATINCRYPT 2023 : 8th International Conference on Cryptology and Information Security in Latin America
EditorsAbdelrahaman Aly, Mehdi Tibouchi
PublisherSpringer
Publication dateOct 2023
Pages273-292
ISBN (Print)9783031444685
DOIs
Publication statusPublished - Oct 2023
Event8th International Conference on Cryptology and Information Security in Latin America - Quito, Ecuador
Duration: 3. Oct 20233. Oct 2023

Conference

Conference8th International Conference on Cryptology and Information Security in Latin America
Country/TerritoryEcuador
CityQuito
Period03/10/202303/10/2023
SeriesLecture Notes in Computer Science
ISSN0302-9743

Keywords

  • Merkle trees
  • authenticity
  • digital signatures
  • fake news
  • quotable signatures

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