2026-07-09 –, P2P Portal
Private payments rely on a global uniqueness guarantee to prevent double-spends, making them incompatible with local-first architectures. This talk explores introducing trusted hardware to remove this requirement, enabling a design that is local-first, but still uses consensus as a fallback.
Most private payments decouple spent assets from newly created assets by maintaining unlinkable sets of commitments and nullifiers. Since these sets are inherently global states, every transaction must refer to the latest global state to prove its validity. A trusted hardware guarantee removes this requirement, since it can maintain a monotonically increasing counter that is impossible to double-spend. We introduce a design that uses trusted hardware for the local-first mode, and falls back to global consensus for defense-in-depth against hardware failures.
Ying Tong is an applied cryptographer working on private payments.