feat: send and receive unflattened public inputs to backend (#3543)

Author: TomAFrench

compiler/integration-tests/test/node/smart_contract_verifier.test.ts

@@ -7,7 +7,7 @@ import toml from 'toml';
 
 import { compile, init_log_level as compilerLogLevel } from '@noir-lang/noir_wasm';
 import { Noir } from '@noir-lang/noir_js';
-import { BarretenbergBackend } from '@noir-lang/backend_barretenberg';
+import { BarretenbergBackend, flattenPublicInputs } from '@noir-lang/backend_barretenberg';
 
 compilerLogLevel('INFO');
 
@@ -59,7 +59,7 @@ test_cases.forEach((testInfo) => {
 
     const contract = await ethers.deployContract(testInfo.compiled, [], {});
 
-    const result = await contract.verify(proofData.proof, proofData.publicInputs);
+    const result = await contract.verify(proofData.proof, flattenPublicInputs(proofData.publicInputs));
 
     expect(result).to.be.true;
   });

tooling/noir_js_backend_barretenberg/src/index.ts

@@ -3,6 +3,9 @@ import { decompressSync as gunzip } from 'fflate';
 import { acirToUint8Array } from './serialize.js';
 import { Backend, CompiledCircuit, ProofData } from '@noir-lang/types';
 import { BackendOptions } from './types.js';
+import { deflattenPublicInputs, flattenPublicInputsAsArray } from './public_inputs.js';
+
+export { flattenPublicInputs } from './public_inputs.js';
 
 // This is the number of bytes in a UltraPlonk proof
 // minus the public inputs.
@@ -18,7 +21,7 @@ export class BarretenbergBackend implements Backend {
   private acirUncompressedBytecode: Uint8Array;
 
   constructor(
-    acirCircuit: CompiledCircuit,
+    private acirCircuit: CompiledCircuit,
     private options: BackendOptions = { threads: 1 },
   ) {
     const acirBytecodeBase64 = acirCircuit.bytecode;
@@ -91,16 +94,8 @@ export class BarretenbergBackend implements Backend {
     const splitIndex = proofWithPublicInputs.length - numBytesInProofWithoutPublicInputs;
 
     const publicInputsConcatenated = proofWithPublicInputs.slice(0, splitIndex);
-
-    const publicInputSize = 32;
-    const publicInputs: Uint8Array[] = [];
-
-    for (let i = 0; i < publicInputsConcatenated.length; i += publicInputSize) {
-      const publicInput = publicInputsConcatenated.slice(i, i + publicInputSize);
-      publicInputs.push(publicInput);
-    }
-
     const proof = proofWithPublicInputs.slice(splitIndex);
+    const publicInputs = deflattenPublicInputs(publicInputsConcatenated, this.acirCircuit.abi);
 
     return { proof, publicInputs };
   }
@@ -185,26 +180,13 @@ export class BarretenbergBackend implements Backend {
 
 function reconstructProofWithPublicInputs(proofData: ProofData): Uint8Array {
   // Flatten publicInputs
-  const publicInputsConcatenated = flattenUint8Arrays(proofData.publicInputs);
+  const publicInputsConcatenated = flattenPublicInputsAsArray(proofData.publicInputs);
 
   // Concatenate publicInputs and proof
   const proofWithPublicInputs = Uint8Array.from([...publicInputsConcatenated, ...proofData.proof]);
 
   return proofWithPublicInputs;
 }
 
-function flattenUint8Arrays(arrays: Uint8Array[]): Uint8Array {
-  const totalLength = arrays.reduce((acc, val) => acc + val.length, 0);
-  const result = new Uint8Array(totalLength);
-
-  let offset = 0;
-  for (const arr of arrays) {
-    result.set(arr, offset);
-    offset += arr.length;
-  }
-
-  return result;
-}
-
 // typedoc exports
 export { Backend, BackendOptions, CompiledCircuit, ProofData };

tooling/noir_js_backend_barretenberg/src/public_inputs.ts

@@ -0,0 +1,87 @@
+import { Abi, WitnessMap } from '@noir-lang/types';
+
+export function flattenPublicInputs(publicInputs: WitnessMap): string[] {
+  const publicInputIndices = [...publicInputs.keys()].sort();
+  const flattenedPublicInputs = publicInputIndices.map((index) => publicInputs.get(index) as string);
+  return flattenedPublicInputs;
+}
+
+export function flattenPublicInputsAsArray(publicInputs: WitnessMap): Uint8Array {
+  const flatPublicInputs = flattenPublicInputs(publicInputs);
+  const flattenedPublicInputs = flatPublicInputs.map(hexToUint8Array);
+  return flattenUint8Arrays(flattenedPublicInputs);
+}
+
+export function deflattenPublicInputs(flattenedPublicInputs: Uint8Array, abi: Abi): WitnessMap {
+  const publicInputSize = 32;
+  const chunkedFlattenedPublicInputs: Uint8Array[] = [];
+
+  for (let i = 0; i < flattenedPublicInputs.length; i += publicInputSize) {
+    const publicInput = flattenedPublicInputs.slice(i, i + publicInputSize);
+    chunkedFlattenedPublicInputs.push(publicInput);
+  }
+
+  const return_value_witnesses = abi.return_witnesses;
+  const public_parameters = abi.parameters.filter((param) => param.visibility === 'public');
+  const public_parameter_witnesses: number[] = public_parameters.flatMap((param) =>
+    abi.param_witnesses[param.name].flatMap((witness_range) =>
+      Array.from({ length: witness_range.end - witness_range.start }, (_, i) => witness_range.start + i),
+    ),
+  );
+
+  // We now have an array of witness indices which have been deduplicated and sorted in ascending order.
+  // The elements of this array should correspond to the elements of `flattenedPublicInputs` so that we can build up a `WitnessMap`.
+  const public_input_witnesses = [...new Set(public_parameter_witnesses.concat(return_value_witnesses))].sort();
+
+  const publicInputs: WitnessMap = new Map();
+  public_input_witnesses.forEach((witness_index, index) => {
+    const witness_value = uint8ArrayToHex(chunkedFlattenedPublicInputs[index]);
+    publicInputs.set(witness_index, witness_value);
+  });
+
+  return publicInputs;
+}
+
+function flattenUint8Arrays(arrays: Uint8Array[]): Uint8Array {
+  const totalLength = arrays.reduce((acc, val) => acc + val.length, 0);
+  const result = new Uint8Array(totalLength);
+
+  let offset = 0;
+  for (const arr of arrays) {
+    result.set(arr, offset);
+    offset += arr.length;
+  }
+
+  return result;
+}
+
+function uint8ArrayToHex(buffer: Uint8Array): string {
+  const hex: string[] = [];
+
+  buffer.forEach(function (i) {
+    let h = i.toString(16);
+    if (h.length % 2) {
+      h = '0' + h;
+    }
+    hex.push(h);
+  });
+
+  return '0x' + hex.join('');
+}
+
+function hexToUint8Array(hex: string): Uint8Array {
+  const sanitised_hex = BigInt(hex).toString(16).padStart(64, '0');
+
+  const len = sanitised_hex.length / 2;
+  const u8 = new Uint8Array(len);
+
+  let i = 0;
+  let j = 0;
+  while (i < len) {
+    u8[i] = parseInt(sanitised_hex.slice(j, j + 2), 16);
+    i += 1;
+    j += 2;
+  }
+
+  return u8;
+}

tooling/noir_js_types/src/types.ts

@@ -1,4 +1,6 @@
-import { Abi } from '@noir-lang/noirc_abi';
+import { Abi, WitnessMap } from '@noir-lang/noirc_abi';
+
+export { Abi, WitnessMap } from '@noir-lang/noirc_abi';
 
 export interface Backend {
   /**
@@ -43,7 +45,7 @@ export interface Backend {
  * */
 export type ProofData = {
   /** @description Public inputs of a proof */
-  publicInputs: Uint8Array[];
+  publicInputs: WitnessMap;
   /** @description An byte array representing the proof */
   proof: Uint8Array;
 };