Create task task-029

backlog/tasks/task-029 - zkGPS-Protocol-Design.md

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+---
+id: task-029
+title: zkGPS Protocol Design
+status: To Do
+assignee: []
+created_date: '2025-12-04 21:12'
+labels:
+  - feature
+  - privacy
+  - cryptography
+  - research
+dependencies: []
+priority: medium
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Design and implement a zero-knowledge proof system for privacy-preserving location sharing. Enables users to prove location claims without revealing exact coordinates.
+
+Key capabilities:
+- Proximity proofs: Prove "I am within X distance of Y" without revealing exact location
+- Region membership: Prove "I am in Central Park" without revealing which part
+- Temporal proofs: Prove "I was in region R between T1 and T2"
+- Group rendezvous: N people prove they are all nearby without revealing locations to each other
+
+Technical approaches to evaluate:
+- ZK-SNARKs (Groth16, PLONK) for succinct proofs
+- Bulletproofs for range proofs on coordinates
+- Geohash commitments for variable precision
+- Homomorphic encryption for distance calculations
+- Ring signatures for group privacy
+
+Integration with canvas:
+- Share location with configurable precision per trust circle
+- Verify location claims from network participants
+- Display verified presence without exact coordinates
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [ ] #1 Protocol specification document complete
+- [ ] #2 Proof-of-concept proximity proof working
+- [ ] #3 Geohash commitment scheme implemented
+- [ ] #4 Trust circle precision configuration UI
+- [ ] #5 Integration with canvas presence system
+- [ ] #6 Performance benchmarks acceptable for real-time use
+<!-- AC:END -->