utils.ts•10.6 kB
/*! noble-curves - MIT License (c) 2022 Paul Miller (paulmillr.com) */
// 100 lines of code in the file are duplicated from noble-hashes (utils).
// This is OK: `abstract` directory does not use noble-hashes.
// User may opt-in into using different hashing library. This way, noble-hashes
// won't be included into their bundle.
const _0n = BigInt(0);
const _1n = BigInt(1);
const _2n = BigInt(2);
const u8a = (a: any): a is Uint8Array => a instanceof Uint8Array;
export type Hex = Uint8Array | string; // hex strings are accepted for simplicity
export type PrivKey = Hex | bigint; // bigints are accepted to ease learning curve
export type CHash = {
(message: Uint8Array | string): Uint8Array;
blockLen: number;
outputLen: number;
create(opts?: { dkLen?: number }): any; // For shake
};
export type FHash = (message: Uint8Array | string) => Uint8Array;
const hexes = /* @__PURE__ */ Array.from({ length: 256 }, (_, i) =>
i.toString(16).padStart(2, '0')
);
/**
* @example bytesToHex(Uint8Array.from([0xca, 0xfe, 0x01, 0x23])) // 'cafe0123'
*/
export function bytesToHex(bytes: Uint8Array): string {
if (!u8a(bytes)) throw new Error('Uint8Array expected');
// pre-caching improves the speed 6x
let hex = '';
for (let i = 0; i < bytes.length; i++) {
hex += hexes[bytes[i]];
}
return hex;
}
export function numberToHexUnpadded(num: number | bigint): string {
const hex = num.toString(16);
return hex.length & 1 ? `0${hex}` : hex;
}
export function hexToNumber(hex: string): bigint {
if (typeof hex !== 'string') throw new Error('hex string expected, got ' + typeof hex);
// Big Endian
return BigInt(hex === '' ? '0' : `0x${hex}`);
}
/**
* @example hexToBytes('cafe0123') // Uint8Array.from([0xca, 0xfe, 0x01, 0x23])
*/
export function hexToBytes(hex: string): Uint8Array {
if (typeof hex !== 'string') throw new Error('hex string expected, got ' + typeof hex);
const len = hex.length;
if (len % 2) throw new Error('padded hex string expected, got unpadded hex of length ' + len);
const array = new Uint8Array(len / 2);
for (let i = 0; i < array.length; i++) {
const j = i * 2;
const hexByte = hex.slice(j, j + 2);
const byte = Number.parseInt(hexByte, 16);
if (Number.isNaN(byte) || byte < 0) throw new Error('Invalid byte sequence');
array[i] = byte;
}
return array;
}
// BE: Big Endian, LE: Little Endian
export function bytesToNumberBE(bytes: Uint8Array): bigint {
return hexToNumber(bytesToHex(bytes));
}
export function bytesToNumberLE(bytes: Uint8Array): bigint {
if (!u8a(bytes)) throw new Error('Uint8Array expected');
return hexToNumber(bytesToHex(Uint8Array.from(bytes).reverse()));
}
export function numberToBytesBE(n: number | bigint, len: number): Uint8Array {
return hexToBytes(n.toString(16).padStart(len * 2, '0'));
}
export function numberToBytesLE(n: number | bigint, len: number): Uint8Array {
return numberToBytesBE(n, len).reverse();
}
// Unpadded, rarely used
export function numberToVarBytesBE(n: number | bigint): Uint8Array {
return hexToBytes(numberToHexUnpadded(n));
}
/**
* Takes hex string or Uint8Array, converts to Uint8Array.
* Validates output length.
* Will throw error for other types.
* @param title descriptive title for an error e.g. 'private key'
* @param hex hex string or Uint8Array
* @param expectedLength optional, will compare to result array's length
* @returns
*/
export function ensureBytes(title: string, hex: Hex, expectedLength?: number): Uint8Array {
let res: Uint8Array;
if (typeof hex === 'string') {
try {
res = hexToBytes(hex);
} catch (e) {
throw new Error(`${title} must be valid hex string, got "${hex}". Cause: ${e}`);
}
} else if (u8a(hex)) {
// Uint8Array.from() instead of hash.slice() because node.js Buffer
// is instance of Uint8Array, and its slice() creates **mutable** copy
res = Uint8Array.from(hex);
} else {
throw new Error(`${title} must be hex string or Uint8Array`);
}
const len = res.length;
if (typeof expectedLength === 'number' && len !== expectedLength)
throw new Error(`${title} expected ${expectedLength} bytes, got ${len}`);
return res;
}
/**
* Copies several Uint8Arrays into one.
*/
export function concatBytes(...arrays: Uint8Array[]): Uint8Array {
const r = new Uint8Array(arrays.reduce((sum, a) => sum + a.length, 0));
let pad = 0; // walk through each item, ensure they have proper type
arrays.forEach((a) => {
if (!u8a(a)) throw new Error('Uint8Array expected');
r.set(a, pad);
pad += a.length;
});
return r;
}
export function equalBytes(b1: Uint8Array, b2: Uint8Array) {
// We don't care about timing attacks here
if (b1.length !== b2.length) return false;
for (let i = 0; i < b1.length; i++) if (b1[i] !== b2[i]) return false;
return true;
}
// Global symbols in both browsers and Node.js since v11
// See https://github.com/microsoft/TypeScript/issues/31535
declare const TextEncoder: any;
/**
* @example utf8ToBytes('abc') // new Uint8Array([97, 98, 99])
*/
export function utf8ToBytes(str: string): Uint8Array {
if (typeof str !== 'string') throw new Error(`utf8ToBytes expected string, got ${typeof str}`);
return new Uint8Array(new TextEncoder().encode(str)); // https://bugzil.la/1681809
}
// Bit operations
/**
* Calculates amount of bits in a bigint.
* Same as `n.toString(2).length`
*/
export function bitLen(n: bigint) {
let len;
for (len = 0; n > _0n; n >>= _1n, len += 1);
return len;
}
/**
* Gets single bit at position.
* NOTE: first bit position is 0 (same as arrays)
* Same as `!!+Array.from(n.toString(2)).reverse()[pos]`
*/
export function bitGet(n: bigint, pos: number) {
return (n >> BigInt(pos)) & _1n;
}
/**
* Sets single bit at position.
*/
export const bitSet = (n: bigint, pos: number, value: boolean) => {
return n | ((value ? _1n : _0n) << BigInt(pos));
};
/**
* Calculate mask for N bits. Not using ** operator with bigints because of old engines.
* Same as BigInt(`0b${Array(i).fill('1').join('')}`)
*/
export const bitMask = (n: number) => (_2n << BigInt(n - 1)) - _1n;
// DRBG
const u8n = (data?: any) => new Uint8Array(data); // creates Uint8Array
const u8fr = (arr: any) => Uint8Array.from(arr); // another shortcut
type Pred<T> = (v: Uint8Array) => T | undefined;
/**
* Minimal HMAC-DRBG from NIST 800-90 for RFC6979 sigs.
* @returns function that will call DRBG until 2nd arg returns something meaningful
* @example
* const drbg = createHmacDRBG<Key>(32, 32, hmac);
* drbg(seed, bytesToKey); // bytesToKey must return Key or undefined
*/
export function createHmacDrbg<T>(
hashLen: number,
qByteLen: number,
hmacFn: (key: Uint8Array, ...messages: Uint8Array[]) => Uint8Array
): (seed: Uint8Array, predicate: Pred<T>) => T {
if (typeof hashLen !== 'number' || hashLen < 2) throw new Error('hashLen must be a number');
if (typeof qByteLen !== 'number' || qByteLen < 2) throw new Error('qByteLen must be a number');
if (typeof hmacFn !== 'function') throw new Error('hmacFn must be a function');
// Step B, Step C: set hashLen to 8*ceil(hlen/8)
let v = u8n(hashLen); // Minimal non-full-spec HMAC-DRBG from NIST 800-90 for RFC6979 sigs.
let k = u8n(hashLen); // Steps B and C of RFC6979 3.2: set hashLen, in our case always same
let i = 0; // Iterations counter, will throw when over 1000
const reset = () => {
v.fill(1);
k.fill(0);
i = 0;
};
const h = (...b: Uint8Array[]) => hmacFn(k, v, ...b); // hmac(k)(v, ...values)
const reseed = (seed = u8n()) => {
// HMAC-DRBG reseed() function. Steps D-G
k = h(u8fr([0x00]), seed); // k = hmac(k || v || 0x00 || seed)
v = h(); // v = hmac(k || v)
if (seed.length === 0) return;
k = h(u8fr([0x01]), seed); // k = hmac(k || v || 0x01 || seed)
v = h(); // v = hmac(k || v)
};
const gen = () => {
// HMAC-DRBG generate() function
if (i++ >= 1000) throw new Error('drbg: tried 1000 values');
let len = 0;
const out: Uint8Array[] = [];
while (len < qByteLen) {
v = h();
const sl = v.slice();
out.push(sl);
len += v.length;
}
return concatBytes(...out);
};
const genUntil = (seed: Uint8Array, pred: Pred<T>): T => {
reset();
reseed(seed); // Steps D-G
let res: T | undefined = undefined; // Step H: grind until k is in [1..n-1]
while (!(res = pred(gen()))) reseed();
reset();
return res;
};
return genUntil;
}
// Validating curves and fields
const validatorFns = {
bigint: (val: any) => typeof val === 'bigint',
function: (val: any) => typeof val === 'function',
boolean: (val: any) => typeof val === 'boolean',
string: (val: any) => typeof val === 'string',
stringOrUint8Array: (val: any) => typeof val === 'string' || val instanceof Uint8Array,
isSafeInteger: (val: any) => Number.isSafeInteger(val),
array: (val: any) => Array.isArray(val),
field: (val: any, object: any) => (object as any).Fp.isValid(val),
hash: (val: any) => typeof val === 'function' && Number.isSafeInteger(val.outputLen),
} as const;
type Validator = keyof typeof validatorFns;
type ValMap<T extends Record<string, any>> = { [K in keyof T]?: Validator };
// type Record<K extends string | number | symbol, T> = { [P in K]: T; }
export function validateObject<T extends Record<string, any>>(
object: T,
validators: ValMap<T>,
optValidators: ValMap<T> = {}
) {
const checkField = (fieldName: keyof T, type: Validator, isOptional: boolean) => {
const checkVal = validatorFns[type];
if (typeof checkVal !== 'function')
throw new Error(`Invalid validator "${type}", expected function`);
const val = object[fieldName as keyof typeof object];
if (isOptional && val === undefined) return;
if (!checkVal(val, object)) {
throw new Error(
`Invalid param ${String(fieldName)}=${val} (${typeof val}), expected ${type}`
);
}
};
for (const [fieldName, type] of Object.entries(validators)) checkField(fieldName, type!, false);
for (const [fieldName, type] of Object.entries(optValidators)) checkField(fieldName, type!, true);
return object;
}
// validate type tests
// const o: { a: number; b: number; c: number } = { a: 1, b: 5, c: 6 };
// const z0 = validateObject(o, { a: 'isSafeInteger' }, { c: 'bigint' }); // Ok!
// // Should fail type-check
// const z1 = validateObject(o, { a: 'tmp' }, { c: 'zz' });
// const z2 = validateObject(o, { a: 'isSafeInteger' }, { c: 'zz' });
// const z3 = validateObject(o, { test: 'boolean', z: 'bug' });
// const z4 = validateObject(o, { a: 'boolean', z: 'bug' });