Paper 2022/1551

Extensible Decentralized Secret Sharing and Application to Schnorr Signatures

Michele Battagliola, University of Trento
Riccardo Longo, University of Trento
Alessio Meneghetti, University of Trento

Starting from links between coding theory and secret sharing we develop an extensible and decentralized version of Shamir Secret Sharing, that allows the addition of new users after the initial shares distribution. On top of it we design a totally decentralized $(t,n)$-threshld Schnorr signature scheme that needs only $t$ users online during the key generation phase, while the others join later. Under standard assumptions we prove our scheme secure against adaptive malicious adversaries. Furthermore, we show how our security notion can be strengthen when considering a rushing adversary. Using a classical game-based argument, we prove that if there is an adversary capable of forging the scheme with non-negligible probability, then we can build a forger for the centralized Schnorr scheme with non-negligible probability.

Note: Preliminary version, will be updated soon.

Available format(s)
Cryptographic protocols
Publication info
Secret Sharing VSS Schnorr Signature Threshold Signature
Contact author(s)
michele battagliola @ unitn it
riccardolongomath @ gmail com
alessio meneghetti @ unitn it
2022-11-08: approved
2022-11-08: received
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Short URL
Creative Commons Attribution-ShareAlike


      author = {Michele Battagliola and Riccardo Longo and Alessio Meneghetti},
      title = {Extensible Decentralized Secret Sharing and Application to Schnorr Signatures},
      howpublished = {Cryptology ePrint Archive, Paper 2022/1551},
      year = {2022},
      note = {\url{}},
      url = {}
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