Smart Contract-based Secure Verifiable Random Function using ChaCha20 Sequence in Blockchain

Bong Gon Kim, Dennis Wong

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)


We provide a novel smart contract-based Verifiable Random Function (VRF) scheme that addresses the challenges associated with existing frameworks. Our suggested distributed VRF instantiation employs multi-party computation (MPC) within a blockchain network, ensuring collective randomness and security by preventing any singular participant from predicting the VRF's output. We endeavor to augment the stochastic nature of our VRF system by incorporating a cryptographically secure ChaCha20 sequence for the generation of pseudo-random sequences. We consider the forward security by adapting Identity-based Encryption (IBE) and show a cryptographic VRF construction, based on Elgamal Encryption and Discrete Logarithm Problem (DLP)-based cryptographic primitives with Decentralized Identifier (DID) for the MPC operations. The construction presents how to prove the correctness of the VRF's outputs with proofs, rendering it applicable for use cases necessitating random yet verifiable values. Moreover, we show the security analysis with formal proofs and entropy approximation for the randomness of the VRF output. Furthermore, employing the NIST SP800-22 randomness test suite for statistical randomness evaluation, our result shows an overall pass rate of 96.59% across a total of 176 tests encompassing 11 standard test cases. The average p -value is observed as 0.5728, indicative of relevant statistical randomness within the generated sequences. We also provide specific details on the implementation of our VRF scheme within a Solidity smart contract.

Original languageEnglish
Title of host publicationICBCT 2023 - 2023 5th International Conference on Blockchain Technology
PublisherAssociation for Computing Machinery
Number of pages11
ISBN (Electronic)9798400716508
Publication statusPublished - 10 Nov 2023
Event5th International Conference on Blockchain Technology, ICBCT 2023 - Virtual, Guilin, China
Duration: 10 Nov 202312 Nov 2023

Publication series

NameACM International Conference Proceeding Series


Conference5th International Conference on Blockchain Technology, ICBCT 2023
CityVirtual, Guilin


  • Blockchain
  • ChaCha20 Cipher
  • Entropy
  • Identity-Based Encryption
  • MPC
  • NIST SP800-22
  • Smart Contract
  • Verifiable Random Function


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