Use snarkjs API and remove the hardcoding of the snarkjs command line path

circuits/ts/index.ts

@@ -2,14 +2,26 @@ import * as fs from 'fs'
 import * as path from 'path'
 import * as shelljs from 'shelljs'
 import * as tmp from 'tmp'
+import { zKey, groth16 } from 'snarkjs'
 
 import { stringifyBigInts } from 'maci-crypto'
 
-const snarkjsPath = path.join(
-    __dirname,
-    '..',
-    './node_modules/snarkjs/cli.js',
-)
+/*
+ * https://github.com/iden3/snarkjs/issues/152
+ * Need to cleanup the threads to avoid stalling
+ */
+const cleanThreads = async () => {
+    if (!globalThis) {
+      return Promise.resolve(true)
+    }
+
+    const curves = ['curve_bn128', 'curve_bls12381']
+    const promises = Promise.all(curves.map(curve => {
+       return globalThis[curve]?.terminate? globalThis[curve]?.terminate() : null
+    }).filter(Boolean))
+
+    return promises
+}
 
 const genProof = (
     inputs: string[],
@@ -71,69 +83,16 @@ const genProof = (
     return { proof, publicInputs }
 }
 
-const verifyProof = (
-    publicInputs: any,
-    proof: any,
-    vk: any,
-) => {
-    // Create tmp directory
-    const tmpObj = tmp.dirSync()
-    const tmpDirPath = tmpObj.name
-
-    const publicJsonPath = path.join(tmpDirPath, 'public.json')
-    const proofJsonPath = path.join(tmpDirPath, 'proof.json')
-    const vkJsonPath = path.join(tmpDirPath, 'vk.json')
-
-    fs.writeFileSync(
-        publicJsonPath,
-        JSON.stringify(stringifyBigInts(publicInputs)),
-    )
-
-    fs.writeFileSync(
-        proofJsonPath,
-        JSON.stringify(stringifyBigInts(proof)),
-    )
-
-    fs.writeFileSync(
-        vkJsonPath,
-        JSON.stringify(stringifyBigInts(vk)),
-    )
-
-    const verifyCmd = `node ${snarkjsPath} g16v ${vkJsonPath} ${publicJsonPath} ${proofJsonPath}`
-    const output = shelljs.exec(verifyCmd, { silent: true })
-    const isValid = output.stdout && output.stdout.indexOf('OK!') > -1
-
-    //// Generate calldata
-    //const calldataCmd = `node ${snarkjsPath} zkesc ${publicJsonPath} ${proofJsonPath}`
-    //console.log(shelljs.exec(calldataCmd).stdout)
-
-    fs.unlinkSync(proofJsonPath)
-    fs.unlinkSync(publicJsonPath)
-    fs.unlinkSync(vkJsonPath)
-    tmpObj.removeCallback()
-
+const verifyProof = async (publicInputs: any, proof: any, vk: any) => {
+    const isValid = await groth16.verify(vk, publicInputs, proof)
+    await cleanThreads()
     return isValid
 }
 
-const extractVk = (zkeyPath: string) => {
-    // Create tmp directory
-    const tmpObj = tmp.dirSync()
-    const tmpDirPath = tmpObj.name
-    const vkJsonPath = path.join(tmpDirPath, 'vk.json')
-
-    const exportCmd = `node ${snarkjsPath} zkev ${zkeyPath} ${vkJsonPath}`
-    shelljs.exec(exportCmd)
-
-    const vk = JSON.parse(fs.readFileSync(vkJsonPath).toString())
-
-    fs.unlinkSync(vkJsonPath)
-    tmpObj.removeCallback()
-
+const extractVk = async (zkeyPath: string) => {
+    const vk = await zKey.exportVerificationKey(zkeyPath)
+    await cleanThreads()
     return vk
 }
 
-export {
-    genProof,
-    verifyProof,
-    extractVk,
-}
+export { genProof, verifyProof, extractVk }

circuits/ts/snarkjs.d.ts

@@ -0,0 +1,28 @@
+declare module 'snarkjs' {
+    export type NumericString = `${number}` | string
+    export type PublicSignals = NumericString[]
+
+    export interface Groth16Proof {
+        pi_a: NumericString[];
+        pi_b: NumericString[][];
+        pi_c: NumericString[];
+        protocol: string;
+        curve: string;
+    }
+
+    export namespace zKey {
+        function exportVerificationKey(
+            zkeyName: any,
+            logger?: any,
+        ): Promise<any>
+    }
+
+    export namespace groth16 {
+        function verify(
+            _vk_verifier: any,
+            _publicSignals: PublicSignals,
+            _proof: Groth16Proof,
+            logger?: any,
+        ): Promise<boolean>
+    }
+}

cli/ts/checkVerifyingKey.ts

@@ -126,8 +126,8 @@ const checkVerifyingKey = async (args: any) => {
     const pmZkeyFile = path.resolve(args.process_messages_zkey)
     const tvZkeyFile = path.resolve(args.tally_votes_zkey)
 
-    const processVk: VerifyingKey = VerifyingKey.fromObj(extractVk(pmZkeyFile))
-    const tallyVk: VerifyingKey = VerifyingKey.fromObj(extractVk(tvZkeyFile))
+    const processVk: VerifyingKey = VerifyingKey.fromObj(await extractVk(pmZkeyFile))
+    const tallyVk: VerifyingKey = VerifyingKey.fromObj(await extractVk(tvZkeyFile))
 
     const signer = await getDefaultSigner()
     if (!await contractExists(signer.provider, maciAddress)) {

cli/ts/genProofs.ts

@@ -232,12 +232,12 @@ const genProofs = async (args: any) => {
             return 1
         }
 
-        subsidyVk = extractVk(args.subsidy_zkey)
+        subsidyVk = await extractVk(args.subsidy_zkey)
     }
 
     // Extract the verifying keys
-    const processVk = extractVk(args.process_zkey)
-    const tallyVk = extractVk(args.tally_zkey)
+    const processVk = await extractVk(args.process_zkey)
+    const tallyVk = await extractVk(args.tally_zkey)
 
     // The coordinator's MACI private key
     let serializedPrivkey
@@ -394,7 +394,7 @@ const genProofs = async (args: any) => {
         }
 
         // Verify the proof
-        const isValid = verifyProof(
+        const isValid = await verifyProof(
             r.publicInputs,
             r.proof,
             processVk,
@@ -440,7 +440,7 @@ const genProofs = async (args: any) => {
             subsidyCircuitInputs = poll.subsidyPerBatch()
             const r = genProof(subsidyCircuitInputs, rapidsnarkExe, args.subsidy_witnessgen, args.subsidy_zkey)
 
-            const isValid = verifyProof(r.publicInputs, r.proof, subsidyVk) 
+            const isValid = await verifyProof(r.publicInputs, r.proof, subsidyVk)
             if (!isValid) {
                 console.error('Error: generated an invalid subsidy calc proof')
                 return 1
@@ -501,7 +501,7 @@ const genProofs = async (args: any) => {
         )
 
         // Verify the proof
-        const isValid = verifyProof(
+        const isValid = await verifyProof(
             r.publicInputs,
             r.proof,
             tallyVk,

cli/ts/setVerifyingKeys.ts

@@ -131,8 +131,8 @@ const setVerifyingKeys = async (args: any) => {
         return 1
     }
 
-    const processVk: VerifyingKey = VerifyingKey.fromObj(extractVk(pmZkeyFile))
-    const tallyVk: VerifyingKey = VerifyingKey.fromObj(extractVk(tvZkeyFile))
+    const processVk: VerifyingKey = VerifyingKey.fromObj(await extractVk(pmZkeyFile))
+    const tallyVk: VerifyingKey = VerifyingKey.fromObj(await extractVk(tvZkeyFile))
 
 
     let ssZkeyFile: string
@@ -144,7 +144,7 @@ const setVerifyingKeys = async (args: any) => {
             return 1
         }
 
-        subsidyVk = VerifyingKey.fromObj(extractVk(ssZkeyFile))
+        subsidyVk = VerifyingKey.fromObj(await extractVk(ssZkeyFile))
     }
 
     // Simple validation

integrationTests/integrations.yml

@@ -17,7 +17,7 @@ invalidVote:
   voteCreditBalance: 1
 constants:
   poll:
-    duration: 120
+    duration: 300
     intStateTreeDepth: 1
     messageTreeDepth: 2
     messageBatchDepth: 1

integrationTests/ts/__tests__/suites.ts

@@ -221,7 +221,7 @@ const executeSuite = async (data: any, expect: any) => {
             }
         }
 
-        const timeTravelCommand = `node build/index.js timeTravel -s ${config.constants.maci.votingDuration}`
+        const timeTravelCommand = `node build/index.js timeTravel -s ${config.constants.poll.duration}`
         execute(timeTravelCommand)
 
         const mergeMessagesCommand = `node build/index.js mergeMessages -x ${maciAddress} -o ${pollId}`