From 8120d965b61323a56b16b8531cc342fb48d49cee Mon Sep 17 00:00:00 2001
From: James Zaki <james.zaki@proton.me>
Date: Thu, 11 Apr 2024 15:37:13 +0100
Subject: [PATCH] Single recursive function (WIP)

---
 .../circuits/recurse/src/main.nr              | 30 +++----
 how-to/recursive-proofs/main.ts               | 80 +++++++++++--------
 2 files changed, 60 insertions(+), 50 deletions(-)

diff --git a/how-to/recursive-proofs/circuits/recurse/src/main.nr b/how-to/recursive-proofs/circuits/recurse/src/main.nr
index 385b6d5..14de9a2 100644
--- a/how-to/recursive-proofs/circuits/recurse/src/main.nr
+++ b/how-to/recursive-proofs/circuits/recurse/src/main.nr
@@ -1,22 +1,22 @@
 use dep::std;
 
+// recursive summation
+#[recursive]
 fn main(
     verification_key: [Field; 114],
+    proof: [Field; 93],
     public_inputs: [Field; 1],
     key_hash: Field,
-    proof1: [Field; 93],
-    proof2: [Field; 93]
-) {
-    std::verify_proof(
-        verification_key.as_slice(),
-        proof1.as_slice(),
-        public_inputs.as_slice(),
-        key_hash
-    );
-    std::verify_proof(
-        verification_key.as_slice(),
-        proof2.as_slice(),
-        public_inputs.as_slice(),
-        key_hash
-    );
+    sum: Field,
+    n: Field
+) -> pub u64 {
+    if (key_hash != 0) {
+        std::verify_proof(
+            verification_key.as_slice(),
+            proof.as_slice(),
+            public_inputs.as_slice(),
+            key_hash
+        );
+    }
+    sum as u64 + n as u64
 }
diff --git a/how-to/recursive-proofs/main.ts b/how-to/recursive-proofs/main.ts
index c2305f5..edcdfa7 100644
--- a/how-to/recursive-proofs/main.ts
+++ b/how-to/recursive-proofs/main.ts
@@ -35,45 +35,55 @@ type FullNoir = {
 }
 
 async function start() {
-  const simple: FullNoir = await fullNoirFromCircuit('not_odd');
-  const outer: FullNoir = await fullNoirFromCircuit('recurse');
+  const recursive: FullNoir = await fullNoirFromCircuit('recurse');
 
-  // Generate inner proof artifacts
-  console.log("Generating intermediate proof artifacts 1...");
-  const innerWitness1 = (await simple.noir.execute({ n: 2 })).witness;
-  const innerProof1: ProofData = await simple.backend.generateProof(innerWitness1);
-  const artifacts1 = await simple.backend.generateRecursiveProofArtifacts(innerProof1, 1);
-
-  console.log("Generating intermediate proof artifacts 2...");
-  const innerWitness2 = (await simple.noir.execute({ n: 4 })).witness;
-  const innerProof2: ProofData = await simple.backend.generateProof(innerWitness2);
-  const artifacts2 = await simple.backend.generateRecursiveProofArtifacts(innerProof2, 1);
-
-  simple.backend.destroy();
-
-  // Generate and verify outer proof
-  const outerInput = {
-    verification_key: artifacts1.vkAsFields,
-    public_inputs: ["1"], // expect output of inner call to be "true"
-    key_hash: artifacts1.vkHash,
-    proof1: artifacts1.proofAsFields,
-    proof2: artifacts2.proofAsFields
+  // Generate artifacts recursively
+  let verificationProof = {
+    verification_key: Array<string>(114).fill("0x00"),
+    proof: Array<string>(93).fill("0x00"),
+    public_inputs: ["0x06"],
+    key_hash: "0x00" as string, // circuit should skip `verify_proof` when key_hash is 0.
   };
-  const outerWitness = (await outer.noir.execute(
-    outerInput
-  )).witness;
-  try {
-    console.log("Generating outer proof...");
-    const outerProof: ProofData = await outer.backend.generateProof(outerWitness);
-    console.log("Verifying outer proof...");
-    const res: boolean = await outer.backend.verifyProof(outerProof);
-    console.log("Verification", res ? "PASSED" : "failed");
-  }
-  catch (e) {
-    console.log(e);
+  let sum = 1;
+  const nodes = [3, 7];
+  for (const [i, n] of nodes.entries()) {
+    console.log("\n\nExecuting (with key_hash %s, sum %d, n %d)", verificationProof.key_hash, sum, n);
+    verificationProof.public_inputs = ["4"];
+    const { witness, returnValue } = await recursive.noir.execute({
+      ...verificationProof,
+      sum,
+      n
+    });
+    console.log("RESULT:", returnValue, witness);
+    sum = Number(returnValue) as number;
+    console.log("Generating proof data...");
+    const pd: ProofData = await recursive.backend.generateProof(witness);
+    console.log(pd);
+    if (i < nodes.length - 1) {
+      console.log("Generating recursive proof artifacts (depth %d)...", i);
+      ({
+        proofAsFields: verificationProof.proof,
+        vkAsFields: verificationProof.verification_key,
+        vkHash: verificationProof.key_hash
+      } = await recursive.backend.generateRecursiveProofArtifacts(
+        pd,
+        Number(verificationProof.public_inputs[0])
+      ));
+    }
+    else {
+      console.log("Verifying final proof...");
+      try {
+        const res: boolean = await recursive.backend.verifyProof(pd);
+        console.log("Verification", res ? "PASSED" : "failed");
+      }
+      catch (e) {
+        console.log(e);
+      }
+
+    }
   }
 
-  outer.backend.destroy();
+  recursive.backend.destroy();
 }
 
 start();