Paper 2023/1063

DiStefano: Decentralized Infrastructure for Sharing Trusted Encrypted Facts and Nothing More

Alex Davidson, NOVA LINCS & DI, FCT, Universidade NOVA de Lisboa,

Hamed Haddadi, Brave Software, Imperial College London

Gonçalo Pestana, Hashmatter

Joe Rowell, Information Security Group, Royal Holloway, University of London

Abstract

We design DiStefano: an efficient, maliciously-secure framework for generating private commitments over TLS-encrypted web traffic, for verification by a designated third-party. DiStefano provides many improvements over previous TLS commitment systems, including: a modular protocol specific to TLS 1.3, support for arbitrary verifiable claims over encrypted data, client browsing history privacy amongst pre-approved TLS servers, and various optimisations to ensure fast online performance of the TLS 1.3 session. We build a permissive open-source implementation of DiStefano integrated into the BoringSSL cryptographic library (used by Chromium-based Internet browsers). We show that DiStefano is practical in both LAN and WAN settings for committing to facts in arbitrary TLS traffic, requiring \(<\) 1 s and \(≤\) 80 KiB to execute the complete online phase of the protocol.

Note: We note the attack of 2026/540 and mitigations. Thank you 2026/540 authors for pointing it out!

@misc{cryptoeprint:2023/1063,
      author = {Sofía Celi and Alex Davidson and Hamed Haddadi and Gonçalo Pestana and Joe Rowell},
      title = {{DiStefano}: Decentralized Infrastructure for Sharing Trusted Encrypted Facts and Nothing More},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/1063},
      year = {2023},
      url = {https://eprint.iacr.org/2023/1063}
}