Sigui: A Decentralized Identity and Trustless Threat Registry Standard for Autonomous AI Agents (ERC-8259)

Abstract

As the Agentic Economy expands, autonomous AI agents—ranging from algorithmic trading bots on decentralized finance (DeFi) platforms to decentralized physical infrastructure (DePIN) orchestrators—operate with increasing autonomy. However, the absence of a standardized, cross-protocol identity and behavioral reputation layer exposes the ecosystem to coordinated agentic attacks. This paper presents Sigui, alongside the proposed Ethereum standard ERC-8259, which introduces a composable framework for Decentralized Identifiers (DIDs), dynamic reputation scoring, and trustless threat intelligence sharing specifically designed for AI agents operating on EVM-compatible networks. By decoupling identity verification, reputation mutation, and threat pattern hashing, Sigui enables smart contracts to perform zero-latency, on-chain risk assessments of agent transactions. We detail the architecture of the IAgentIdentity, IAgentReputation, and IThreatRegistry interfaces, propose a deterministic cryptographic hashing standard for multi-layered threat patterns, and discuss the economic security and sybil resistance of the protocol. The reference implementation, deployed on the Ethereum Sepolia testnet, demonstrates the feasibility of real-time A2A (Agent-to-Agent) security protocols.