Use isZeroUint8Array to check for empty bytes

This commit is contained in:
dapplion 2020-11-29 23:52:27 +00:00
parent 6fe9b09a92
commit 32266dae20
6 changed files with 46 additions and 17 deletions

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@ -1,9 +1,10 @@
import * as blst from "@chainsafe/blst"; import * as blst from "@chainsafe/blst";
import {bytesToHex, hexToBytes, randomBytes} from "../helpers"; import {bytesToHex, hexToBytes, isZeroUint8Array, randomBytes} from "../helpers";
import {SECRET_KEY_LENGTH} from "../constants"; import {SECRET_KEY_LENGTH} from "../constants";
import {IPrivateKey} from "../interface"; import {IPrivateKey} from "../interface";
import {PublicKey} from "./publicKey"; import {PublicKey} from "./publicKey";
import {Signature} from "./signature"; import {Signature} from "./signature";
import {ZeroPrivateKeyError} from "../errors";
export class PrivateKey implements IPrivateKey { export class PrivateKey implements IPrivateKey {
readonly value: blst.SecretKey; readonly value: blst.SecretKey;
@ -13,6 +14,11 @@ export class PrivateKey implements IPrivateKey {
} }
static fromBytes(bytes: Uint8Array): PrivateKey { static fromBytes(bytes: Uint8Array): PrivateKey {
// draft-irtf-cfrg-bls-signature-04 does not allow SK == 0
if (isZeroUint8Array(bytes)) {
throw new ZeroPrivateKeyError();
}
const sk = blst.SecretKey.fromBytes(bytes); const sk = blst.SecretKey.fromBytes(bytes);
return new PrivateKey(sk); return new PrivateKey(sk);
} }

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@ -3,5 +3,3 @@ export const SIGNATURE_LENGTH = 96;
export const FP_POINT_LENGTH = 48; export const FP_POINT_LENGTH = 48;
export const PUBLIC_KEY_LENGTH = FP_POINT_LENGTH; export const PUBLIC_KEY_LENGTH = FP_POINT_LENGTH;
export const G2_HASH_PADDING = 16; export const G2_HASH_PADDING = 16;
export const EMPTY_PUBLIC_KEY = new Uint8Array(PUBLIC_KEY_LENGTH);
export const EMPTY_SIGNATURE = new Uint8Array(SIGNATURE_LENGTH);

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@ -3,14 +3,6 @@ import randomBytes from "randombytes";
// Single import to ease changing this lib if necessary // Single import to ease changing this lib if necessary
export {randomBytes}; export {randomBytes};
export function isEqualBytes(a: Buffer | Uint8Array, b: Buffer | Uint8Array): boolean {
return toBuffer(a).equals(toBuffer(b));
}
export function toBuffer(input: Uint8Array): Buffer {
return Buffer.from(input.buffer, input.byteOffset, input.length);
}
/** /**
* Validate bytes to prevent confusing WASM errors downstream if bytes is null * Validate bytes to prevent confusing WASM errors downstream if bytes is null
*/ */
@ -24,3 +16,7 @@ export function validateBytes(
} }
} }
} }
export function isZeroUint8Array(bytes: Uint8Array): boolean {
return bytes.every((byte) => byte === 0);
}

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@ -1,7 +1,7 @@
import {PublicKeyType} from "bls-eth-wasm"; import {PublicKeyType} from "bls-eth-wasm";
import {getContext} from "./context"; import {getContext} from "./context";
import {EMPTY_PUBLIC_KEY, PUBLIC_KEY_LENGTH} from "../constants"; import {PUBLIC_KEY_LENGTH} from "../constants";
import {bytesToHex, hexToBytes, isEqualBytes} from "../helpers"; import {bytesToHex, hexToBytes, isZeroUint8Array} from "../helpers";
import {IPublicKey} from "../interface"; import {IPublicKey} from "../interface";
import {ZeroPublicKeyError} from "../errors"; import {ZeroPublicKeyError} from "../errors";
@ -23,7 +23,7 @@ export class PublicKey implements IPublicKey {
const context = getContext(); const context = getContext();
const publicKey = new context.PublicKey(); const publicKey = new context.PublicKey();
if (!isEqualBytes(EMPTY_PUBLIC_KEY, bytes)) { if (!isZeroUint8Array(bytes)) {
publicKey.deserialize(bytes); publicKey.deserialize(bytes);
} }
return new PublicKey(publicKey); return new PublicKey(publicKey);

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@ -1,8 +1,8 @@
import {SIGNATURE_LENGTH, EMPTY_SIGNATURE} from "../constants"; import {SIGNATURE_LENGTH} from "../constants";
import {SignatureType} from "bls-eth-wasm"; import {SignatureType} from "bls-eth-wasm";
import {getContext} from "./context"; import {getContext} from "./context";
import {PublicKey} from "./publicKey"; import {PublicKey} from "./publicKey";
import {bytesToHex, hexToBytes, isEqualBytes} from "../helpers"; import {bytesToHex, hexToBytes, isZeroUint8Array} from "../helpers";
import {ISignature} from "../interface"; import {ISignature} from "../interface";
export class Signature implements ISignature { export class Signature implements ISignature {
@ -23,7 +23,7 @@ export class Signature implements ISignature {
const context = getContext(); const context = getContext();
const signature = new context.Signature(); const signature = new context.Signature();
if (!isEqualBytes(EMPTY_SIGNATURE, bytes)) { if (!isZeroUint8Array(bytes)) {
signature.deserialize(bytes); signature.deserialize(bytes);
} }
return new Signature(signature); return new Signature(signature);

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@ -0,0 +1,29 @@
import {expect} from "chai";
import {isZeroUint8Array} from "../../../src/helpers/utils";
describe("helpers / bytes", () => {
describe("isZeroUint8Array", () => {
const testCases: {isZero: boolean; hex: string}[] = [
{hex: "0x00", isZero: true},
{hex: "0x" + "00".repeat(32), isZero: true},
{hex: "0x" + "00".repeat(96), isZero: true},
{hex: "0x" + "00".repeat(31) + "01", isZero: false},
{
hex: "0xb6f21199594b56d77670564bf422cb331d5281ca2c1f9a45588a56881d8287ef8619efa6456d6cd2ef61306aa5b21311",
isZero: false,
},
];
for (const {hex, isZero} of testCases) {
it(`${hex} isZero = ${isZero}`, () => {
const bytes = hexToBytesNode(hex);
console.log(bytes);
expect(isZeroUint8Array(bytes)).to.equal(isZero);
});
}
});
});
function hexToBytesNode(hex: string): Buffer {
return Buffer.from(hex.replace("0x", ""), "hex");
}