Merge pull request #5 from EYBlockchain/westlad/verify

feat: add verify capability and update zokrates

Dockerfile

@@ -1,11 +1,12 @@
-FROM docker.pkg.github.com/eyblockchain/zokrates-zexe/zokrates_zexe:a6bfd3bf3fa81fc4b4ced9d6b4a998cb240b21fe as builder
+FROM zokrates/zokrates:0.6.3 as builder
 
 # Actual application (for testing purposes)
 FROM node:12
 RUN mkdir /app
 WORKDIR /app
 COPY ./package.json ./package-lock.json ./
-COPY --from=builder /home/zokrates/zokrates /app/zokrates
-COPY --from=builder /home/zokrates/.zokrates* /app/stdlib
+COPY --from=builder /home/zokrates/.zokrates/bin/zokrates /app/
+COPY --from=builder /home/zokrates/.zokrates/stdlib/ /app/
+ENV ZOKRATES_HOME='/app'
 RUN npm ci
 RUN npm install jest --g

index.js

@@ -3,11 +3,13 @@ const computeWitness = require('./lib/compute-witness');
 const extractVk = require('./lib/extract-vk');
 const generateProof = require('./lib/generate-proof');
 const setup = require('./lib/setup');
+const verify = require('./lib/verify');
 
 module.exports = {
   compile,
   computeWitness,
   extractVk,
   generateProof,
   setup,
+  verify,
 };

lib/__tests__/ordered-tests.js

@@ -1,11 +1,13 @@
 const fs = require('fs');
-const deleteFile = require('../utils/utils');
+const jsonfile = require('jsonfile');
 
+const deleteFile = require('../utils/utils');
 const compile = require('../compile');
 const setup = require('../setup');
 const computeWitness = require('../compute-witness');
 const generateProof = require('../generate-proof');
 const extractVk = require('../extract-vk');
+const verify = require('../verify');
 
 describe('Compile tests', () => {
   it('should throw an error if file path does not exists', async () => {
@@ -19,13 +21,13 @@ describe('Compile tests', () => {
   });
 
   it('should create the given output file', async () => {
-    await compile('./code/test.zok', './code/test/', 'test-compiled', 'bls12_377');
+    await compile('./code/test.zok', './code/test/', 'test-compiled', 'bn128');
     expect(fs.existsSync('./code/test/test-compiled')).toBe(true);
     deleteFile('./code/test/test-compiled');
   });
 
   it('should return a string given a verbose flag', async () => {
-    const output = await compile('./code/test.zok', './code/test/', 'test-compiled', 'bls12_377', {
+    const output = await compile('./code/test.zok', './code/test/', 'test-compiled', 'bn128', {
       verbose: true,
     });
     expect(typeof output).toBe('string');
@@ -35,34 +37,34 @@ describe('Setup tests', () => {
   it('should throw an error if file path does not exists', async () => {
     expect.assertions(1);
     await expect(
-      setup('./foo', './code/test/', 'gm17', 'zexe', 'test-vk', 'test-pk'),
+      setup('./foo', './code/test/', 'gm17', 'ark', 'test-vk', 'test-pk'),
     ).rejects.toThrow(Error);
   });
 
   it('should throw an error if input file ends with .zok', async () => {
     expect.assertions(1);
     await expect(
-      setup('./code/test/test-compiled.zok', './code/test/', 'gm17', 'zexe', 'test-vk', 'test-pk'),
+      setup('./code/test/test-compiled.zok', './code/test/', 'gm17', 'ark', 'test-vk', 'test-pk'),
     ).rejects.toThrow(Error);
   });
 
   it('should create the given output file with default names', async () => {
     expect.assertions(2);
-    await setup('./code/test/test-compiled', './code/test/', 'gm17', 'zexe', undefined, undefined);
+    await setup('./code/test/test-compiled', './code/test/', 'gm17', 'ark', undefined, undefined);
     expect(fs.existsSync('./code/test/verification.key')).toBe(true);
     expect(fs.existsSync('./code/test/proving.key')).toBe(true);
     deleteFile('./code/test/verification.key');
     deleteFile('./code/test/proving.key');
   });
 
-  it('should allow GM17 proving scheme with Zexe backend', async () => {
+  it('should allow GM17 proving scheme with ark backend', async () => {
     expect.assertions(1);
     const basePath = './code/test/';
     const vkPath = `${basePath}test-vk.key`;
     const pkPath = `${basePath}test-pk.key`;
 
     // eslint-disable-next-line no-await-in-loop
-    await setup('./code/test/test-compiled', './code/test/', 'gm17', 'zexe', 'test-vk', 'test-pk');
+    await setup('./code/test/test-compiled', './code/test/', 'gm17', 'ark', 'test-vk', 'test-pk');
     expect(fs.existsSync(vkPath) && fs.existsSync(pkPath)).toBe(true);
     deleteFile('./code/test/test-vk.key');
     deleteFile('./code/test/test-pk.key');
@@ -73,7 +75,7 @@ describe('Setup tests', () => {
       './code/test/test-compiled',
       './code/test/',
       'gm17',
-      'zexe',
+      'ark',
       'test-vk',
       'test-pk',
       {
@@ -85,24 +87,15 @@ describe('Setup tests', () => {
 });
 describe('verifier key extraction tests', () => {
   it('should return a json version of the verifier key', async () => {
-    expect.assertions(8);
+    expect.assertions(7);
     const vk = extractVk('./code/test/test-vk.key');
-    expect(Object.keys(vk)).toEqual([
-      'h',
-      'g_alpha',
-      'h_beta',
-      'g_gamma',
-      'h_gamma',
-      'query',
-      'raw',
-    ]);
+    expect(Object.keys(vk)).toEqual(['h', 'g_alpha', 'h_beta', 'g_gamma', 'h_gamma', 'query']);
     expect(vk.h).toEqual(expect.anything());
     expect(vk.g_alpha).toEqual(expect.anything());
     expect(vk.h_beta).toEqual(expect.anything());
     expect(vk.g_gamma).toEqual(expect.anything());
     expect(vk.h_gamma).toEqual(expect.anything());
     expect(vk.query).toEqual(expect.anything());
-    expect(vk.raw).toEqual(expect.anything());
   });
   it('should handle unknown vk filenames gracefully', async () => {
     const vk = extractVk('./code/test/non-existent-filename.key');
@@ -158,7 +151,7 @@ describe('Generate proof tests', () => {
         './code/test/test-compiled',
         './code/test/test-witness',
         'gm17',
-        'zexe',
+        'ark',
         {
           createFile: true,
           directory: './code/',
@@ -168,18 +161,11 @@ describe('Generate proof tests', () => {
     ).rejects.toThrow(Error);
 
     await expect(
-      generateProof(
-        './code/test/test-pk.key',
-        './foo',
-        './code/test/test-witness',
-        'gm17',
-        'zexe',
-        {
-          createFile: true,
-          directory: './code/',
-          fileName: 'test-proof.json',
-        },
-      ),
+      generateProof('./code/test/test-pk.key', './foo', './code/test/test-witness', 'gm17', 'ark', {
+        createFile: true,
+        directory: './code/',
+        fileName: 'test-proof.json',
+      }),
     ).rejects.toThrow(Error);
   });
 
@@ -206,7 +192,7 @@ describe('Generate proof tests', () => {
       './code/test/test-compiled',
       './code/test/test-witness',
       'gm17',
-      'zexe',
+      'ark',
       {
         createFile: true,
         directory: './code/test/',
@@ -222,7 +208,7 @@ describe('Generate proof tests', () => {
       './code/test/test-compiled',
       './code/test/test-witness',
       'gm17',
-      'zexe',
+      'ark',
       {
         createFile: true,
         directory: './code/test/',
@@ -233,3 +219,14 @@ describe('Generate proof tests', () => {
     deleteFile('./code/test/proof.json');
   });
 });
+describe('Verification tests', () => {
+  it('Should verify true, when the proof and verifier are correct', async () => {
+    // get data from existing files to act as inputs for the call
+    const [proof, vk] = await Promise.all([
+      jsonfile.readFile('./code/test/test-proof.json'),
+      jsonfile.readFile('./code/test/test-vk.key'),
+    ]);
+    const response = await verify(vk, proof, 'gm17', 'ark', 'bn128');
+    expect(response).toBe(true);
+  });
+});

lib/generate-proof.js

@@ -23,7 +23,7 @@ const { spawn } = childProcess;
  * @param {String} provingKeyPath - Path to proving key
  * @param {String} codePath - Path to code file (Result of compile that doesn't end in .code)
  * @param {String} provingScheme - Available options are 'g16', 'pghr13', 'gm17'
- * @param {String} backEnd - Available options are 'libsnark', 'bellman', 'zexe'
+ * @param {String} backEnd - Available options are 'libsnark', 'bellman', 'ark'
  * @param {Object} [options] - Options for output
  * @param {Boolean} options.createFile - Whether or not to output a json file
  * @param {String} [options.directory=./] - Directory to output files in
@@ -35,7 +35,7 @@ async function generateProof(
   codePath,
   witnessPath,
   provingScheme = 'gm17',
-  backend = 'zexe',
+  backend = 'ark',
   options = {},
 ) {
   if (!fs.existsSync(codePath)) {

lib/setup.js

@@ -15,15 +15,15 @@ const { spawn } = childProcess;
  * @param {String} codePath - Path of code file to compile
  * @param {String} outputPath - Directory to output, defaults to current directory
  * @param {String} provingScheme - Available options are g16, pghr13, gm17
- * @param {String} backEnd - Available options are 'libsnark', 'bellman', 'zexe'
+ * @param {String} backEnd - Available options are 'libsnark', 'bellman', 'ark'
  * @param {String} vkName - name of verification key file, defaults to verification.key
  * @param {String} pkName - name of proving key file, defaults to proving.key
  */
 async function setup(
   codePath,
   outputPath = './',
   provingScheme = 'gm17',
-  backend = 'zexe',
+  backend = 'ark',
   vkName = 'verification.key',
   pkName = 'proving.key',
   options = {},

lib/verify.js

@@ -0,0 +1,84 @@
+const childProcess = require('child_process');
+const jsonfile = require('jsonfile');
+const deleteFile = require('./utils/utils');
+
+const { spawn } = childProcess;
+const { writeFile } = jsonfile;
+
+/**
+ * Takes in a proof and a verification key and determines if the proof verifies.
+ *
+ * @example
+ * generateProof('./code/ft-mint/ft-mint-pk.key',
+ *   './code/ft-mint/ft-mint-compiled',
+ *   'gm17',
+ *   {
+ *     createFile: true,
+ *     directory: './code/ft-mint',
+ *     fileName: 'ft-mint-proof.json',
+ *   },
+ * );
+ *
+ * @param {String} provingKeyPath - Path to proving key
+ * @param {String} codePath - Path to code file (Result of compile that doesn't end in .code)
+ * @param {String} provingScheme - Available options are 'g16', 'pghr13', 'gm17'
+ * @param {String} backEnd - Available options are 'libsnark', 'bellman', 'ark'
+ * @param {Object} [options] - Options for output
+ * @param {Boolean} options.createFile - Whether or not to output a json file
+ * @param {String} [options.directory=./] - Directory to output files in
+ * @param {String} [options.fileName=proof.json] - Name of JSON proof file ()
+ * @returns {Object} JSON of the proof.
+ */
+async function verify(vk, proof, provingScheme = 'gm17', backend = 'ark', curve = 'bn128') {
+  // we've provided a json proof and a verifying key but Zokrates needs to read
+  // these from a file. Thus we should write them to temporary files.
+  const proofTempFile = '/tmp/proof.json';
+  const vkTempFile = '/tmp/verify.key';
+  await Promise.all([writeFile(vkTempFile, vk), writeFile(proofTempFile, proof)]);
+
+  const args = [
+    'verify',
+    '-v',
+    vkTempFile,
+    '-j',
+    proofTempFile,
+    '--proving-scheme',
+    provingScheme,
+    '--backend',
+    backend,
+    '--curve',
+    curve,
+  ];
+
+  return new Promise((resolve, reject) => {
+    const zokrates = spawn('/app/zokrates', args, {
+      stdio: ['ignore', 'pipe', 'pipe'],
+      env: {
+        ZOKRATES_HOME: '/app/stdlib',
+      },
+    });
+
+    let output = '';
+    zokrates.stdout.on('data', data => {
+      output += data.toString('utf8');
+    });
+
+    zokrates.stderr.on('data', err => {
+      reject(new Error(`Verify failed: ${err}`));
+    });
+
+    zokrates.on('close', () => {
+      // we no longer need the temporary files
+      deleteFile(proofTempFile);
+      deleteFile(vkTempFile);
+      // ZoKrates sometimes outputs error through stdout instead of stderr,
+      // so we need to catch those errors manually.
+      if (output.includes('panicked')) reject(new Error(output.slice(output.indexOf('panicked'))));
+
+      if (output.includes('PASS')) resolve(true);
+      else resolve(false);
+    });
+  });
+}
+
+module.exports = verify;

package.json

@@ -23,7 +23,9 @@
     "jest": "^24.9.0",
     "markdownlint-cli": "^0.18.0"
   },
-  "dependencies": {},
+  "dependencies": {
+    "jsonfile": "^6.1.0"
+  },
   "publishConfig": {
     "registry": "https://npm.pkg.github.com"
   },