We present a new verifiable oblivious pseudorandom function (VOPRF) from isogeny group actions. Our construction is twice as fast as the previous state of the art of Delpech de Saint Guilhem and Pedersen at a slightly higher communication cost. One major contribution is the realization of a new proof protocol that is integrated as a two-party computation into the OPRF protocol, making the output verifiable. The main design choice behind our construction and this new proof system is to enable an easy transformation into a threshold protocol, something previous designs have not achieved. To this end, we present our VOPRF in a modular way based on different subroutines. We show how to replace these subroutines with their threshold counterparts, using simulation-based arguments. This results in the first threshold VOPRF from isogenies and one of the first threshold VOPRFs in the post-quantum literature. In contrast to other post-quantum threshold VOPRF designs, our construction has input and output size independent of the number of server parties and furthermore is robust, while other designs rely on aborts in the presence of malicious parties.

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Threshold Oblivious Pseudorandom Functions from Isogeny Group Actions

  • Robi Pedersen

摘要

We present a new verifiable oblivious pseudorandom function (VOPRF) from isogeny group actions. Our construction is twice as fast as the previous state of the art of Delpech de Saint Guilhem and Pedersen at a slightly higher communication cost. One major contribution is the realization of a new proof protocol that is integrated as a two-party computation into the OPRF protocol, making the output verifiable. The main design choice behind our construction and this new proof system is to enable an easy transformation into a threshold protocol, something previous designs have not achieved. To this end, we present our VOPRF in a modular way based on different subroutines. We show how to replace these subroutines with their threshold counterparts, using simulation-based arguments. This results in the first threshold VOPRF from isogenies and one of the first threshold VOPRFs in the post-quantum literature. In contrast to other post-quantum threshold VOPRF designs, our construction has input and output size independent of the number of server parties and furthermore is robust, while other designs rely on aborts in the presence of malicious parties.