feat: expose verifyNotRoot API

src/codec.spec.ts

@@ -53,6 +53,7 @@ describe("RLN codec with version 0", () => {
 
     expect(msg.rateLimitProof).to.not.be.undefined;
     expect(msg.verify()).to.be.true;
+    expect(msg.verifyNoRoot()).to.be.true;
     expect(msg.epoch).to.not.be.undefined;
     expect(msg.epoch).to.be.gt(0);
 
@@ -92,6 +93,7 @@ describe("RLN codec with version 0", () => {
     expect(msg.rateLimitProof).to.not.be.undefined;
 
     expect(msg.verify()).to.be.true;
+    expect(msg.verifyNoRoot()).to.be.true;
     expect(msg.epoch).to.not.be.undefined;
     expect(msg.epoch).to.be.gt(0);
 
@@ -134,6 +136,7 @@ describe("RLN codec with version 1", () => {
 
     expect(msg.rateLimitProof).to.not.be.undefined;
     expect(msg.verify()).to.be.true;
+    expect(msg.verifyNoRoot()).to.be.true;
     expect(msg.epoch).to.not.be.undefined;
     expect(msg.epoch).to.be.gt(0);
 
@@ -175,6 +178,7 @@ describe("RLN codec with version 1", () => {
     expect(msg.rateLimitProof).to.not.be.undefined;
 
     expect(msg.verify()).to.be.true;
+    expect(msg.verifyNoRoot()).to.be.true;
     expect(msg.epoch).to.not.be.undefined;
     expect(msg.epoch).to.be.gt(0);
 
@@ -216,6 +220,7 @@ describe("RLN codec with version 1", () => {
 
     expect(msg.rateLimitProof).to.not.be.undefined;
     expect(msg.verify()).to.be.true;
+    expect(msg.verifyNoRoot()).to.be.true;
     expect(msg.epoch).to.not.be.undefined;
     expect(msg.epoch).to.be.gt(0);
 
@@ -258,6 +263,7 @@ describe("RLN codec with version 1", () => {
     expect(msg.rateLimitProof).to.not.be.undefined;
 
     expect(msg.verify()).to.be.true;
+    expect(msg.verifyNoRoot()).to.be.true;
     expect(msg.epoch).to.not.be.undefined;
     expect(msg.epoch).to.be.gt(0);
 
@@ -302,6 +308,7 @@ describe("RLN Codec - epoch", () => {
     expect(msg.rateLimitProof).to.not.be.undefined;
 
     expect(msg.verify()).to.be.true;
+    expect(msg.verifyNoRoot()).to.be.true;
     expect(msg.epoch).to.not.be.undefined;
     expect(msg.epoch!.toString(10).length).to.eq(9);
     expect(msg.epoch).to.eq(epoch);

src/message.ts

@@ -22,6 +22,15 @@ export class RlnMessage<T extends Message> implements Message {
       : undefined;
   }
 
+  public verifyNoRoot(): boolean | undefined {
+    return this.rateLimitProof
+      ? this.rlnInstance.verifyWithNoRoot(
+          this.rateLimitProof,
+          toRLNSignal(this)
+        ) // this.rlnInstance.verifyRLNProof once issue status-im/nwaku#1248 is fixed
+      : undefined;
+  }
+
   get payload(): Uint8Array | undefined {
     return this.msg.payload;
   }

src/rln.ts

@@ -225,4 +225,25 @@ export class RLNInstance {
       root
     );
   }
+
+  verifyWithNoRoot(
+    proof: RateLimitProof | Uint8Array,
+    msg: Uint8Array
+  ): boolean {
+    let pBytes: Uint8Array;
+    if (proof instanceof Uint8Array) {
+      pBytes = proof;
+    } else {
+      pBytes = proofToBytes(proof);
+    }
+
+    // calculate message length
+    const msgLen = writeUIntLE(new Uint8Array(8), msg.length, 0, 8);
+
+    return zerokitRLN.verifyWithRoots(
+      this.zkRLN,
+      concatenate(pBytes, msgLen, msg),
+      new Uint8Array()
+    );
+  }
 }