Common Contracts

Making Hash-based MVBA Great Again

Multi-Valued Validated Asynchronous Byzantine Agreement (Mvba) • March 25th, 2024

• Contract Type
  Multi-Valued Validated Asynchronous Byzantine Agreement (Mvba)
• Filed
  March 25th, 2024

Multi-valued Validated Asynchronous Byzantine Agreement (MVBA) is one essential primitive for many distributed protocols, such as asynchronous Byzantine fault-tolerant scenarios like atomic broad- cast (ABC), asynchronous distributed key generation, and many others. Recent efforts (Lu et al, PODC’ 20) have pushed the com- munication complexity of MVBA to optimal ℓ𝑛 𝜆𝑛2 , which, however, heavily rely on “heavyweight” cryptographic tools, such as non-interactive threshold signatures. The computational cost of algebraic operations, the susceptibility to quantum attacks, and the necessity of a trusted setup associated with threshold signa- tures present significant remaining challenges. There is a growing interest in information-theoretic or hash-based constructions (his- torically called signature-free constructions). Unfortunately, the state-of-the-art hash-based MVBA (Duan et al., CCS’23) incurs a large ℓ𝑛2 𝜆𝑛3 -bits communication, which in turn makes the hash-based MVBA inferior perfor