Merge pull request #200 from aion-dk/qz-484-proof-of-election-codes

[QZ-484] Change proof of private key to proof of election codes
aion-dk · Sep 8, 2022 · 1d11d39 · 1d11d39
2 parents 9d56a2a + 9ea8b1b
commit 1d11d39
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Showing 17 changed files with 422 additions and 39 deletions.
diff --git a/.env b/.env
@@ -1,4 +1,5 @@
 DBB_URL="http://dbb:3003/"
 VOTER_AUTHORIZER_URL="http://voter-authorizer:3002/"
+CONFERENCE_HOST_URL="http://localhost:3005/"
 OTP_PROVIDER_URL="http://otp-provider:3001/"
 MAILCATCHER_URL="http://mailcatcher:1080/"
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,4 +1,7 @@
 # AV Client Library Changelog
+## 1.1.6
+- Replace proof-of-private-key with proof-of-election-codes
+
 ## 1.1.5
 - Move authorizationMode under voterAuthorizer and rename values:
   - proof-of-identity and proof-of-private-key

diff --git a/lib/av_client.ts b/lib/av_client.ts
@@ -47,8 +47,8 @@ import { CAST_REQUEST_ITEM, MAX_POLL_ATTEMPTS, POLLING_INTERVAL_MS, SPOIL_REQUES
 import { hexToShortCode, shortCodeToHex } from './av_client/short_codes';
 import { encryptCommitmentOpening, validateCommmitmentOpening } from './av_client/crypto/commitments';
 import { submitBallotCryptograms } from './av_client/actions/submit_ballot_cryptograms';
-import { Curve, DiscreteLogarithmProof } from './av_client/aion_crypto'
 import {AxiosResponse} from "axios";
+import { ProofOfElectionCodes } from "./av_client/crypto/proof_of_election_codes";
 
 /** @internal */
 export const sjcl = sjclLib;
@@ -99,6 +99,7 @@ export class AVClient implements IAVClient {
   private ballotCryptogramItem: BallotCryptogramItem;
   private voterCommitmentOpening: CommitmentOpening;
   private spoilRequest: SpoilRequestItem
+  private proofOfElectionCodes: ProofOfElectionCodes;
 
   /**
    * @param bulletinBoardURL URL to the Assembly Voting backend server, specific for election.
@@ -192,9 +193,13 @@ export class AVClient implements IAVClient {
     this.identityConfirmationToken = await provider.requestOTPAuthorization(code, this.email);
   }
 
+  generateProofOfElectionCodes(electionCodes : Array<string>) {
+    this.proofOfElectionCodes = new ProofOfElectionCodes(electionCodes);
+  }
+
   /**
    * Registers a voter based on the authorization mode of the Voter Authorizer
-   * Authorization is done by 'proof-of-identity' or 'proof-of-private-key'
+   * Authorization is done by 'proof-of-identity' or 'proof-of-election-codes'
    */
   public async createVoterRegistration(): Promise<void> {
     const coordinatorURL = this.getElectionConfig().services.voterAuthorizer.url;
@@ -210,8 +215,11 @@ export class AVClient implements IAVClient {
         throw new InvalidStateError('Cannot register voter without identity confirmation. User has not validated access code.')
 
       authorizationResponse = await this.authorizeIdentity(coordinator)
-    } else if(authorizationMode === 'proof-of-private-key') {
-      authorizationResponse = await this.authorizePrivateKeyProof(coordinator)
+    } else if(authorizationMode === 'proof-of-election-codes') {
+      if(this.proofOfElectionCodes == null)
+        throw new InvalidStateError('Cannot register voter without proof of election codes. User has not generated an election codes proof.')
+
+      authorizationResponse = await coordinator.authorizeProofOfElectionCodes(this.keyPair.publicKey, this.proofOfElectionCodes)
     } else {
       throw new InvalidConfigError('Unknown authorization mode of voter authorizer')
     }
@@ -525,20 +533,6 @@ export class AVClient implements IAVClient {
     );
   }
 
-  /**
-   * Registers a voter by proof of private key
-   * Used when the authorization mode of the Voter Authorizer is 'proof-of-private-key'
-   * @returns AxiosResponse or throws an error
-   */
-  private async authorizePrivateKeyProof(coordinator): Promise<AxiosResponse> {
-    const privateKeyBn = sjcl.bn.fromBits(sjcl.codec.hex.toBits(this.keyPair.privateKey))
-    const proofOfPrivateKey = DiscreteLogarithmProof.generate(Curve.G, privateKeyBn).toString()
-    return await coordinator.authorizeProof(
-        this.keyPair.publicKey,
-        proofOfPrivateKey
-    );
-  }
-
   /**
    * Should be called after spoilBallot.
    * Gets the verifier public key from the DBB

diff --git a/lib/av_client/aion_crypto.js b/lib/av_client/aion_crypto.js
@@ -857,6 +857,19 @@ function addBigNums(bn1_hex, bn2_hex) {
   return sum_hex
 }
 
+/**
+ * Converts an election code string into a big num, for use as a private key.
+ *
+ * The private key is derived using pbkdf2-hmac-sha256.
+ * @param {string} electionCode the code to convert to a private key
+ * @param {number} curveSize the size of the curve in bits, used to determine the size of the private key
+ * @returns {string} the hex representation of the private key
+ */
+function electionCodeToPrivateKey(electionCode, curveSize = 256) {
+  let privateKeyBits = sjcl.misc.pbkdf2(electionCode, "", 10_000, curveSize);
+  return sjcl.codec.hex.fromBits(privateKeyBits);
+}
+
 module.exports = {
   Curve,
   DiscreteLogarithmProof,
@@ -888,4 +901,5 @@ module.exports = {
   //'orderObjectByKeys': orderObjectByKeys,                 // Not used?
   hashString,
   addBigNums,
+  electionCodeToPrivateKey
 }
diff --git a/lib/av_client/connectors/voter_authorization_coordinator.ts b/lib/av_client/connectors/voter_authorization_coordinator.ts
@@ -1,6 +1,7 @@
 import axios, { AxiosInstance, AxiosResponse } from 'axios'
 import { IdentityConfirmationToken } from "./otp_provider";
 import { EmailDoesNotMatchVoterRecordError, NetworkError, UnsupportedServerReplyError, VoterRecordNotFoundError } from "../errors";
+import { ProofOfElectionCodes } from "../crypto/proof_of_election_codes";
 
 export default class VoterAuthorizationCoordinator {
   private backend: AxiosInstance;
@@ -55,11 +56,12 @@ export default class VoterAuthorizationCoordinator {
     })
   }
 
-  authorizeProof(publicKey: string, proof: string): Promise<AxiosResponse> {
+  authorizeProofOfElectionCodes(publicKey: string, proof: ProofOfElectionCodes): Promise<AxiosResponse> {
     return this.backend.post('authorize_proof', {
       electionContextUuid: this.electionContextUuid,
-      publicKey: publicKey,
-      proof: proof
+      voterPublicKey: proof.mainKeyPair.publicKey, // This public key is used by the VA to find the voter to authorize.
+      sessionPublicKey: publicKey, // This public key is used for the auth token
+      proof: proof.proof,
     })
   }
 

diff --git a/lib/av_client/crypto/proof_of_election_codes.ts b/lib/av_client/crypto/proof_of_election_codes.ts
@@ -0,0 +1,21 @@
+import {
+  electionCodeToPrivateKey,
+  addBigNums,
+  generateDiscreteLogarithmProof,
+  generateKeyPair,
+} from "../aion_crypto.js";
+import {KeyPair} from "../types";
+
+export class ProofOfElectionCodes {
+  readonly proof: string;
+  readonly mainKeyPair: KeyPair;
+
+  constructor(electionCodes : Array<string>) {
+    const privateKey = <string>electionCodes
+      .map(electionCode => electionCodeToPrivateKey(electionCode))
+      .reduce(addBigNums);
+    this.proof = generateDiscreteLogarithmProof(privateKey);
+    const { public_key: publicKey } = generateKeyPair(privateKey);
+    this.mainKeyPair = { privateKey, publicKey }
+  }
+}
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@aion-dk/js-client",
-  "version": "1.1.5",
+  "version": "1.1.6",
   "license": "MIT",
   "description": "Assembly Voting JS client",
   "main": "dist/lib/av_client.js",

diff --git a/test/crypto/aion_crypto.test.ts b/test/crypto/aion_crypto.test.ts
@@ -0,0 +1,35 @@
+import { expect } from "chai";
+
+import { electionCodeToPrivateKey } from "../../lib/av_client/aion_crypto.js"
+
+describe("#electionCodeToPrivateKey", () => {
+
+  it("deterministically converts election codes to private keys", () => {
+    const electionCodes = ['s3cr3t5', 'hidden', '1', 'sellus', 's3cr3t5'];
+
+    const privateKeys = electionCodes.map(electionCode => electionCodeToPrivateKey(electionCode));
+
+    expect(privateKeys).to.eql([
+      '631a1838f1e82b7b39f2b620a790de69ca8feb0cfd4ba984350a5fe3a2fda299',
+      '502b2a265be9cb1d3b25028904ca63687b5384bf862ad1c5ae8929f31e2afd39',
+      'a259f4b44e30abc0cd53379381bdc86f44723911a5bc03bf4ff21d1b49b53efd',
+      '1c4e46d624d7de41249bd8d3e5538f3464d43c23e22251468a356c29926b1c24',
+      '631a1838f1e82b7b39f2b620a790de69ca8feb0cfd4ba984350a5fe3a2fda299',
+    ]);
+  });
+
+  it('generates a hex string representing 32 bytes (64 nibbles)', () => {
+    const privateKey = electionCodeToPrivateKey('test');
+
+    expect(privateKey.length).to.eql(64);
+  })
+
+  context('when creating keys for a different curve size', () => {
+    it('generates a hex string representing 16 bytes (32 nibbles)', () => {
+      const privateKey = electionCodeToPrivateKey('test', 128);
+
+      expect(privateKey.length).to.eql(32);
+    })
+  })
+})
+
diff --git a/test/crypto/proof_of_election_code.test.ts b/test/crypto/proof_of_election_code.test.ts
@@ -0,0 +1,41 @@
+import { expect } from "chai";
+import { ProofOfElectionCodes } from "../../lib/av_client/crypto/proof_of_election_codes";
+import { DiscreteLogarithmProof, Curve } from "../../lib/av_client/aion_crypto.js"
+import { pointFromHex } from "../../lib/av_client/crypto/util";
+
+describe("Proof of election codes", () => {
+
+  it("converts a single election code into a keyPair", () => {
+    const electionCode = 's3cr3t5';
+
+    const proof = new ProofOfElectionCodes([electionCode]);
+
+    expect(proof.mainKeyPair).to.eql({
+      privateKey: "631a1838f1e82b7b39f2b620a790de69ca8feb0cfd4ba984350a5fe3a2fda299",
+      publicKey: "021d1ccab6d4bc1e4cea12a13d291b2f5772f0c10e8ed4ac4c30be348137005759",
+    });
+  })
+
+  it("converts multiple election codes into a keyPair", () => {
+    const electionCodes = ['s3cr3t5','t0','k33p'];
+
+    const proof = new ProofOfElectionCodes(electionCodes);
+
+    expect(proof.mainKeyPair).to.eql({
+      privateKey: "e71d8edd52ff20ff8a741a9ae0f651193e183eafd639ebde02c847b2a35f9a8d",
+      publicKey: "020936bd7dacd0bfc974c717877fff2b0c4257a3ef0ea545b6acca9fa3e7857463"
+    });
+  })
+
+  it("generates a discrete logarithm proof", () => {
+    const electionCodes = ['s3cr3t5','t0','k33p'];
+
+    const proof = new ProofOfElectionCodes(electionCodes);
+    const discreteLogarithmProof = DiscreteLogarithmProof.fromString(proof.proof);
+
+    expect(proof.proof).to.exist;
+    const publicKey = pointFromHex(proof.mainKeyPair.publicKey).toEccPoint();
+    expect(discreteLogarithmProof.verifyWithoutChallenge(Curve.G, publicKey)).to.be.true;
+  })
+})
+
diff --git a/test/replies/otp_flow/get_b54bf489_3234d498d846_20_configuration.json b/test/replies/otp_flow/get_b54bf489_3234d498d846_20_configuration.json
@@ -0,0 +1,102 @@
+{
+  "electionConfig": {
+    "dbbPublicKey": "03a05ae5f22282d04ca5655bb5903d05c8f4e0d1ec37eeb34ba4c228f88c626156",
+    "encryptionKey": "0232c3623ad6dec442ac0284fe50fda0f96af187f0b1d36cbed065e3fbf1c5639f",
+    "thresholdConfig": {
+      "encryptionKey": "0232c3623ad6dec442ac0284fe50fda0f96af187f0b1d36cbed065e3fbf1c5639f",
+      "threshold": 1,
+      "trustees": [
+        {
+          "publicKey": "0232c3623ad6dec442ac0284fe50fda0f96af187f0b1d36cbed065e3fbf1c5639f",
+          "id": 22,
+          "polynomialCoefficients": []
+        }
+      ]
+    },
+    "curveName": "secp256r1",
+    "services": {
+      "voterAuthorizer": {
+        "electionContextUuid": "a5ac8cfd-ba29-4016-b559-8abbdb8c9daf",
+        "publicKey": "0290a6759edfc186fd71077ba165edfb13df8f14b2741f96c7518ab1749a8e19c5",
+        "url": "http://localhost:3005/voting/b54bf489",
+        "authorizationMode": "proof-of-election-codes"
+      },
+      "otpProvider": {
+        "electionContextUuid": "a5ac8cfd-ba29-4016-b559-8abbdb8c9daf",
+        "publicKey": "0290a6759edfc186fd71077ba165edfb13df8f14b2741f96c7518ab1749a8e19c5",
+        "url": "http://localhost:3005/voting/b54bf489"
+      }
+    },
+    "ballotConfigs": {
+      "20": {
+        "reference": "20",
+        "voterGroup": "20",
+        "contestReferences": [
+          "20"
+        ]
+      }
+    },
+    "contestConfigs": {
+      "20": {
+        "reference": "20",
+        "markingType": {
+          "blankSubmission": "active_choice",
+          "minMarks": 1,
+          "maxMarks": 1,
+          "encoding": {
+            "codeSize": 1,
+            "maxSize": 1,
+            "cryptogramCount": 1
+          }
+        },
+        "options": [
+          {
+            "reference": "2b6e8b8ed9b52fed",
+            "code": 1,
+            "title": {
+              "en": "It tolls for the fallen",
+              "da": "Den ringer for de faldne",
+              "de": "Es läutet für die Gefallenen"
+            }
+          },
+          {
+            "reference": "e30fe1fc5bc910ba",
+            "code": 2,
+            "title": {
+              "en": "It tolls for abandoned",
+              "da": "Den ringer for de efterladte",
+              "de": "Es läutet für die Verlassenen"
+            }
+          },
+          {
+            "reference": "2b842e4ff597b603",
+            "code": 3,
+            "title": {
+              "en": "It tolls for thee",
+              "da": "Den ringer for dig",
+              "de": "Es läutet für dich"
+            }
+          }
+        ],
+        "title": {
+          "en": "Example ballot",
+          "da": "Eksempel valgseddel",
+          "de": "Beispielwahlzettel"
+        },
+        "resultType": {
+          "name": "regular"
+        }
+      }
+    },
+    "genesisConfig": {
+      "publicKey": "03a05ae5f22282d04ca5655bb5903d05c8f4e0d1ec37eeb34ba4c228f88c626156",
+      "authorizationMode": null,
+      "curveName": "secp256r1"
+    },
+    "latestConfigAddress": "f6021d9a93c4e9029c47034f5b1aac617ce6be0a1ffeaa291c2f659f9f430e9e",
+    "status": "open",
+    "sessionTimeout": 5400,
+    "bcTimeout": 600
+  },
+  "receipt": "73b2ba304b971e9512c682ca2ed8886ba9d883adc13fc1fc69022c3ec30f834d,2fbad62bf787943ceb3b9299aab3e56ac7720b9e517a5a0673708d6cf5a22561"
+}
diff --git a/test/replies/otp_flow/post_b54bf489_3234d498d846_20_voting_cast.json b/test/replies/otp_flow/post_b54bf489_3234d498d846_20_voting_cast.json
@@ -0,0 +1,13 @@
+{
+  "castRequest": {
+    "address": "d98b752d71039dc3df90ab138768ba669a08fc9d7e0c2d8b2eeabfc3ab07c338",
+    "author": "voter-voter1",
+    "parentAddress": "5600090a77bb4f28592ebdc81684cf6cb55c53dbc10496447b70848e3eaac854",
+    "previousAddress": "5600090a77bb4f28592ebdc81684cf6cb55c53dbc10496447b70848e3eaac854",
+    "content": {},
+    "registeredAt": "2022-09-07T10:33:58.924Z",
+    "signature": "97b6e799db3b080c2d1ff8c8c8a2e21b0bed0b1f99efb895ea07d07d6a737f54,c03d61089244f654a88c1f041f7da9301a373ec4fbc342c8923fdfbcc1287c15",
+    "type": "CastRequestItem"
+  },
+  "receipt": "46e84599096bc60b29b5daff1cf6c023a1d390d853ca58f3d7c85fda741ac86b,b06fbdaa3a518d1b97cb20528e0c438926651eed2e382920617cd3c7bbbd6e88"
+}
diff --git a/test/replies/otp_flow/post_b54bf489_3234d498d846_20_voting_commitments.json b/test/replies/otp_flow/post_b54bf489_3234d498d846_20_voting_commitments.json
@@ -0,0 +1,32 @@
+{
+  "voterCommitment": {
+    "address": "c17e7052c7a03d26f60cbe2b7e6f2c89218f041f6997b7363846d2bd8da246c6",
+    "author": "voter-voter1",
+    "parentAddress": "b46ac871df62bafaaa168206351f13125c4b9fab95940f57ee1eb50d5da6075e",
+    "previousAddress": "b46ac871df62bafaaa168206351f13125c4b9fab95940f57ee1eb50d5da6075e",
+    "content": {
+      "commitment": "0257dd5f15cc762d05505b7059aaf1fef8906fd17da6da7a634eddecac41107ed8"
+    },
+    "registeredAt": "2022-09-07T10:33:58.234Z",
+    "signature": "f8e5015846a9ca9746fad9558024d44ad85ea5d5dc994656d4d4a2d3b2b38608,befe98c896599e2c34657ea550eef07cb24b8e13609b754b275c5a770b9d1156",
+    "type": "VoterEncryptionCommitmentItem"
+  },
+  "boardCommitment": {
+    "address": "5ad13e017aed983ee275d1be1e53b5a92a36d676034a0570abdc4f7d247e3031",
+    "author": "Digital Ballot Box",
+    "parentAddress": "c17e7052c7a03d26f60cbe2b7e6f2c89218f041f6997b7363846d2bd8da246c6",
+    "previousAddress": "c17e7052c7a03d26f60cbe2b7e6f2c89218f041f6997b7363846d2bd8da246c6",
+    "content": {
+      "commitment": "03aba50419328423ea27434a71c5877bb928607ebc5e7b161095a2e11b90485a82"
+    },
+    "registeredAt": "2022-09-07T10:33:58.362Z",
+    "signature": "2eba8eda5ac77db6e2d0797ba5497dc833b414e6e89e88fd635d47b106cbc7f0,027f85dfc17795c61500bf7e753d0465f8f29b2cdd1267f5db33f88ea0c76790",
+    "type": "BoardEncryptionCommitmentItem"
+  },
+  "envelopes": {
+    "20": [
+      "02cde9f5187eb610fddfcd20f745a8a1f831810d67744ffbc1b01f7ae534ea8eb9,0255b4f9f7595ea66188eb0c7271cb1eaf30dca7d2b13d83c71643ddf97a3d21be"
+    ]
+  },
+  "receipt": "7d15d68985283253847adf52f97239c5d904e12e0ff0930010a4e88ea22ff442,506a1c08952787dc11b9aad642b14414989d3aa7c0d5d3194e7361e7354e2f57"
+}