Location Proof with SP1 zkVM

Zero knowledge proof system for iOSstyle location attestations (in this project: represented as a P256 ECDSA singature) using SP1. Proves that a cryptographically signed location satisfies a constraint (bounding box, circle, or polygon) without revealing the exact coordinates.

• PrivacyPreserving: Exact coordinates never leave the zkVM; only constraint satisfaction is proven
• Cryptographic Verification: P256 ECDSA signature verification inside the zkVM (without precompile optimizations)
• Constraint Types: Bounding box, circular radius, or arbitrary polygon regions
• Constraint parameters are hashed (SHA256) and committed in the proof

Quick Start

Prerequisites

• Rust (with cargo)
• SP1 toolchain installed (instructions)

1. Generate a Mock Location Attestation

Create a signed attestation for New York City coordinates:

cd crates/attestation_mock_client
cargo run -- gen --lat-deg 40.7128 --lon-deg=-74.0060 --out ../../att_nyc.json

This produces an attestation JSON file with:

• Scaled coordinates (lat/lon as i64 with 1e7 scaling factor)
• Random nonce
• P256 ECDSA signature
• Public key embedded in the attestation object

2. Execute Proof with a Bounding Box Constraint

Run the SP1 program in execute mode (fast, no proof generation) to verify a bounding box constraint:

cd crates/location_proof/
cargo run --release -- \
  --execute \
  --attestation-path ../../att_nyc.json \
  --constraint-type 0 \
  --bbox-min-lat 406000000 \
  --bbox-min-lon=-741500000 \
  --bbox-max-lat 408000000 \
  --bbox-max-lon=-739000000

Output:

Program executed successfully.
Constraint satisfied: true
Constraint type: 0
Timestamp: 1765864876
Constraint (raw): bbox:406000000,-741500000,408000000,-739000000
Local hash (sha256): 36024381730ed32139f6e73ecb8193d6dcc5b3a949949503b6c3d3efd477d834
Public hash: 36024381730ed32139f6e73ecb8193d6dcc5b3a949949503b6c3d3efd477d834
Hash match: true
Total cycles: 12379555

3. Try Other Constraint Types

Circle constraint (10km radius around a point):

cargo run --release -- \
  --execute \
  --attestation-path ../../att_nyc.json \
  --constraint-type 1 \
  --circle-lat 407128000 \
  --circle-lon=-740060000 \
  --circle-radius-m 10000

Polygon constraint:

cargo run --release -- \
  --execute \
  --attestation-path ../../att_nyc.json \
  --constraint-type 2 \
  --polygon-coords "406000000,-742000000,408000000,-742000000,408000000,-738000000,406000000,-738000000"

4. Submit to Succinct Prover Network

Folow the intructions to deposit PROVE into your requester account: https://docs.succinct.xyz/docs/sp1/prover-network/quickstart then run

cargo run --bin network --release -- --attestation-path ../../att_nyc.json   --constraint-type 0   --bbox-min-lat 406000000   --bbox-min-lon=-741500000   --bbox-max-lat 408000000   --bbox-max-lon=-739000000

Crates Structure

• crates/attestation_mock_client: Generate mock signed attestations
• crates/attestation_types: Shared types for attestations
• crates/attestation_verifier: P256 signature verification and geometry checks
• crates/location_proof/:
  • program/: Contains program whose execution is being proved
  • script/: Scripts for local execution / submitting to succinct network

General Ideas

1. Attestation Generation: Mock client generates a P256 signed attestation with lat/lon/timestamp
2. zkVM Execution: SP1 program verifies the signature and checks constraint satisfaction
3. Public Output: Only the constraint hash, satisfaction result, and timestamp are revealed
4. Privacy: Exact coordinates only revealed to prover

Coordinate Scaling

All coordinates use a fixed scaling factor of 1e7:

• 37.7749° → 377749000
• -122.4194° → -1224194000

This allows integer arithmetic while preserving ~1cm precision.