An ACA-Py Adaptation Layer for Ethereum Blockchain Network’s Self-Sovereign Identity (SSI) Support

Abstract

Self-Sovereign Identity (SSI) empowers users to manage their digital identities independently, but many systems are constrained to specific blockchains. Aries Cloud Agent Python (ACA-Py), based on Hyperledger Aries, supports decentralized identity but is limited to Hyperledger Indy, excluding Ethereum ecosystems. This paper proposes an adaptation layer that integrates ACA-Py with Ethereum by converting identity operations to Ethereum Virtual Machine (EVM)-compatible formats. The layer uses Python middleware (e.g., Registry.py, Wallet.py) and Solidity smart contracts (e.g., AnonCredRegistry, DIDManagement) for DID registration, schema publication, and credential management on-chain. Motivated by Ethereum's smart contract capabilities, this enhances SSI in EVM networks, enabling identity-based access controls and automated verifications. Unlike developing a new agent, this preserves ACA-Py's architecture, ensuring reusability and compliance with W3C DID/VC standards and Aries RFCs. Implemented with Python, Solidity, and Truffle Suite, the layer was tested on Ganache, validating credential issuance, verification, and DID anchoring. Evaluations showed low latencies (e.g., schema addition: 137 ms) and gas costs (e.g., DID registration: ~50,000 gas). A STRIDE-based security analysis confirms minimal vulnerabilities. This framework promotes interoperable SSI in EVM environments without core modifications.