iacr.orgpaper

zkPoPE: A Transport-Agnostic Security Model for zkTLS (Reclaim Protocol)

This IACR ePrint paper introduces zkPoPE (Zero-Knowledge Proof of Protocol Execution), the first transport-agnostic security model for zkTLS, formalized as a UC ideal functionality that separates "proof of an actual protocol execution occurred" from a plain NIZK over input-output pairs. The authors formally analyze the Reclaim Protocol, showing it UC-realizes zkPoPE under a deployment-aligned trust model, and introduce Distributed-AEAD, a new three-party authenticated-encryption primitive enabling Reclaim to attest a 1200kB TLS response on a lower-mid-range phone in 7.28s — two orders of magnitude larger than previously benchmarked zkTLS schemes. It matters because it gives zkTLS constructions (used for privacy-preserving web attestations) a common, construction-independent security definition to be proven against, rather than each scheme inventing its own.