feat: implement Zero-Knowlde circuits and logic for attaching metadat…

… to exact geopoint proof

contracts/src/logic/public/ExactGeoPoint.ts

@@ -1,7 +1,8 @@
-import { Field } from "o1js";
+import { Field, Poseidon } from "o1js";
 import { GeoPoint } from "../../model/Geography";
-import { GeoPointCommitment } from "../../model/public/Commitment";
+import { GeoPointCommitment, MetadataGeoPointCommitment } from "../../model/public/Commitment";
 import { GeoPointProviderCircuitProof } from "../../zkprogram/private/Geography";
+import { Bytes64, SHA3_512 } from "../../model/public/SHA3";
 
 
 /*
@@ -21,3 +22,16 @@ export function proveExactGeoPointFromProvider(geoPointProviderProof: GeoPointPr
         geoPointHash: geoPointHash
     });
 }
+
+
+export function attachMetadataToGeoPoint(geoPointProviderProof: GeoPointProviderCircuitProof, sha3_512: Bytes64): MetadataGeoPointCommitment {
+    geoPointProviderProof.verify();
+    const geoPoint: GeoPoint = geoPointProviderProof.publicOutput;
+    const geoPointHash: Field = geoPoint.hash();
+    const sha3_512PoseidonHash: Field = Poseidon.hash(sha3_512.toFields());
+
+    return new MetadataGeoPointCommitment({
+        geoPointHash: geoPointHash,
+        metadataHash: sha3_512PoseidonHash
+    });
+}

contracts/src/model/public/Commitment.ts

@@ -6,4 +6,14 @@ export class GeoPointCommitment extends Struct({
   toString(): string {
     return `GeoPoint: ${this.geoPointHash.toString()}`;
   }
-}
+}
+
+export class MetadataGeoPointCommitment extends Struct({
+  geoPointHash: Field,
+  metadataHash: Field,
+}) {
+  toString(): string {
+    return `GeoPoint ${this.geoPointHash.toString()}. Metadata: ${this.metadataHash.toString()}`;
+  }
+}
+

contracts/src/zkprogram/public/Metadata.ts

@@ -0,0 +1,31 @@
+import { ZkProgram } from "o1js";
+import { MetadataGeoPointCommitment } from "../../model/public/Commitment";
+import { GeoPointProviderCircuitProof } from "../private/Geography";
+import { attachMetadataToGeoPoint} from "../../logic/public/ExactGeoPoint";
+import { SHA3_512 } from "../../model/public/SHA3";
+
+// TODO | IMPORTANT //
+// Add a method to ExactGeolocationMetadataCircuit that takes two recursive proofs as inputs:
+// 1. GeoPointProviderCircuitProof
+// 2. A proof that returns SHA3_512.provable as its public output. This way, it's possible to attached authenticated metadata.
+//    This is much better than passing metadata as magic value, since the circuit that produces the metadata itself can
+//    perform verifiable association of the metadata to the GeoPoint in question. For example, the circuit that produced the proof, can
+//    commit the metadata to a particular GeoPoint, and verify that that metadata is indeed associated to that GeoPont.
+
+/*
+* Set of Zero-Knowledge Circuits for associating arbitrary metadata to an exact GeoPoint proof.
+*
+* Visibility: Public
+*/
+export const ExactGeolocationMetadataCircuit = ZkProgram({
+    name: "ExactGeoPointMetadataCircuit",
+    publicOutput: MetadataGeoPointCommitment,
+    methods: {
+        attachMetadataToGeoPoint: {
+            privateInputs: [GeoPointProviderCircuitProof, SHA3_512.provable],
+            method: attachMetadataToGeoPoint,
+        }
+    }
+});
+
+export class ExactGeolocationMetadataCircuitProof extends ZkProgram.Proof(ExactGeolocationMetadataCircuit) { }