Paper 2025/2039

Non-Delegatable Commitments

Pranav Garimidi, a16z Crypto Research

Guru-Vamsi Policharla, University of California, Berkeley

Max Resnick, Anza

Ertem Nusret Tas, a16z Crypto Research

Abstract

Cryptographic commitments allow a party to commit to a value such that it is infeasible to later open that commitment to a different value. Standard commitment schemes allow the committer to outsource both the generation of the commitment and the openings to a third party. This is benign for most use cases; however, when commitments serve as cryptographic attestations of work such as storing data or relaying blocks, participants can outsource the task and still claim credit, undermining the intended economic properties of the protocol. This work initiates the study of non-delegatable commitments, a new primitive where forming a commitment requires possession of a private key, and delegating the commitment process necessarily leaks that key. We formally define the primitive and provide a generic construction from a polynomial commitment scheme in the random oracle model. Additionally, we show how this primitive can be applied to solve a variety of mechanism design problems.

@misc{cryptoeprint:2025/2039,
      author = {Georg Fuchsbauer and Pranav Garimidi and Guru-Vamsi Policharla and Max Resnick and Ertem Nusret Tas},
      title = {Non-Delegatable Commitments},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/2039},
      year = {2025},
      url = {https://eprint.iacr.org/2025/2039}
}