Technical Brief
1. Problem Statement
1.1 GPS Spoofing & Location Fraud
Modern digital infrastructure relies heavily on GPS for location-dependent services. However, GPS signals were not originally designed for security. They are trivially spoofable at the OS level using mock-location applications, emulators, or signal replayers.
1.2 Impact on Digital Economies
Location fraud results in billions of dollars in losses annually, particularly in:
- Mobile Ad-Tech: Payment for impressions or clicks that did not occur in the claimed geographic region.
- Logistics & Delivery: Lack of verifiable proof for regional delivery claims.
- Regional Compliance: Inability to strictly enforce geographic boundaries for regulated services.
1.3 The Gap
Existing solutions rely on IP-based geolocation (imprecise and easily bypassed via VPNs) or software-only checks (vulnerable to compromised operating systems). There is no standard for hardware-anchored, verifiable location proofs.
2. System Overview
GeoProof is the verification layer built on the GEO Protocol, designed to convert location data into a billable utility through hardware-anchored proofs.
2.1 TEE Layer (Trusted Execution Environment)
The core of GeoProof's trust model on the GEO Protocol is the use of hardware-isolated secure enclaves (e.g., ARM TrustZone, Apple Secure Enclave, Android Keystore with StrongBox). These environments are isolated from the main Operating System (OS), making them resistant to OS-level tampering and spoofing.
2.2 Cryptographic Verification
Location data is captured and signed directly within the TEE. This creates a "GeoProof" packet that includes coordinates, secure timestamps, and hardware attestation.
2.3 Spatial Indexing (S2 Geometry)
GeoProof utilizes Google's S2 Geometry library for deterministic spatial indexing on the GEO Protocol, allowing for efficient regional mapping and scalable auditing.
3. Verification Flow
Request
An application requests a location proof for a specific event (e.g., an ad impression).
Capture
The GeoProof SDK interacts with the device's hardware enclave to capture raw location signals.
Signing
The TEE signs the location data and timestamp using a unique, hardware-rooted key.
Proof Generation
A GeoProof packet is generated, containing the signed data and attestation certificate.
Submission
The packet is sent to the GeoProof Verification API.
Validation
The API validates the hardware signature, checks for signal consistency, and verifies the spatial index (S2 cell) on the GEO Protocol.
Result
A boolean verification result is returned, accompanied by a unique Verification Hash for auditing.
4. Trust Model
Assumptions
- Hardware Integrity: TEE hardware has not been compromised at the silicon level.
- Signal Source: Initial raw GPS signal is legitimate; heuristics detect replaying.
Limitations
- Early Stage: Implementation is a technical prototype.
- Device Support: Requires modern hardware with compatible enclaves.
- Latency: Verification adds ~1.5s - 2.0s to the event lifecycle.
5. Current Status
GeoProof is currently in the Alpha Stage on the GEO Protocol. A working proof-generation loop is under implementation using simulated TEE environments, and a test environment is active for early integration testing.