(2026-05) Hybrid PoA on Aztec; Proof of Asset Ownership over Public and Private Balances via Hierarchical Proof-Carrying Data
2026-05-05
Proof of Assets (PoA) protocols enable custodians to prove ownership of digital assets without revealing their account addresses or corresponding balances. While existing PoA protocols focused on either private or public balances, hybrid-state blockchains such as the Aztec Network involve both. In these systems, private balances are managed by encrypted notes that work similarly to the UTXO model, with only commitments stored on-chain. We present a PoA protocol that supports hybrid balances by combining public-state membership proofs with proofs of ownership over private notes. Since a custodian may control multiple accounts and numerous notes, we employ hierarchical proof-carrying data via recursive zk-SNARK, enabling scalable proving and efficient batch verification. We implement our system using the Noir DSL with the UltraHonk proving backend, and evaluate the performance.