Post Quantum transaction signature (PQTS) Breakout #15

Protocol Calls & happenings
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Agenda

Meeting Time: Wednesday, September 16, 2026 at 13:00 UTC (60 minutes)

GitHub Issue

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Meeting Summary:

This meeting was the Post Quantum Transaction Signature Breakout Room #15, focused on presentations and demos related to quantum-resistant signature technologies. Stefano presented significant progress on zero-knowledge proof of seed solutions for hardware wallets, demonstrating that proofs can run on Ledger devices within memory constraints and showing three different lifting implementations (Stark, SP1, and Flock) with varying performance characteristics. The team achieved on-device proving for hardened child key statements taking 3 hours and 22 megabytes of proof, while elliptic curve statements requiring 1GB of proof can now run within days due to 350x optimization improvements since the previous presentation. Alessandro and Matteo then demonstrated Sphinx signature verification across different hardware wallets (Trezor, Ledger Nano S Plus) through their testnet, showing that while software signing takes only 60 milliseconds, hardware wallet verification takes around 10-12 seconds due to proof verification requirements rather than actual signature computation. The team discussed ongoing work including secure OS integration for master key proofs and plans for signature aggregation features in future iterations.

Click to expand detailed summary

Antonio opened the Post Quantum Transaction Signature Breakout Room meeting on September 16, 2026, and outlined the agenda which included a presentation and demo on zero knowledge proof of seed by Stefano, as well as a presentation on the post-quantum signatures testnet. Giulio was thanked for setting up the testnet infrastructure, which currently supports non-native account abstraction. The meeting was scheduled to include a demo on the network using Sphinx-like signatures by the RivaLabs team.

Stefano presented progress on a quantum break emergency mitigation solution that can run on hardware wallets, focusing on proof lifting techniques using zero-knowledge proofs. The implementation includes three different lifters (Stark, SP1, and Flock) with SP1 being the most viable for current L1 implementation at 280k gas for verification. While on-device proving is complete, the team still needs to implement the aggregation step and batching to reduce costs for emergency scenarios involving multiple accounts. The solution requires further work on secure OS integration for master key and seed entropy proofs, and the team plans to focus on optimizing the Flock implementation for the next phase.

Stefano presented an update on their work involving hardware wallet integration, discussing performance differences between devices like the Flex and Nano S Plus, with most functionality fitting on the Nano S Plus despite some tuning challenges. Alessandro and Matteo demonstrated a Sphinx+ signing implementation comparing software wallet signing (60 milliseconds) with hardware wallet performance, showing a 10-12 second signing time on Ledger and Trezor devices due to proof verification requirements. The team explained that the current performance bottlenecks are primarily due to IO constraints and proof transmission rather than actual cryptographic computation, with plans to optimize these aspects in future hardware implementations.

Next Steps:

  • Giulio: Add more information about gas costs and transaction trace logs on the testnet explorer.
  • Stefano: Focus on the Flock implementation for the next step of proof lifting and aggregation.
  • Stefano: Complete the aggregation and batching steps for the proof lifters, especially for the Flock implementation.
  • Stefano: Run the full lifting for the “elephant” proofs (involving elliptic curve operations) beyond 96 responses.
  • Antonio: Prepare and present a formalization paper on the cryptographic security of the Sphinx signing process in the next or next next meeting.
  • RiverLabs (Matteo Vena): Share more public information about the MPC design in the future.

Recording Access:

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YouTube recording available: https://youtu.be/6luxEj07IiI