753 lines
18 KiB
JavaScript
753 lines
18 KiB
JavaScript
'use strict';
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Object.defineProperty(exports, '__esModule', { value: true });
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const _ZERO = BigInt(0);
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const _ONE = BigInt(1);
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const _TWO = BigInt(2);
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/**
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* Absolute value. abs(a)==a if a>=0. abs(a)==-a if a<0
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*
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* @param {number|bigint} a
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*
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* @returns {bigint} the absolute value of a
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*/
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function abs(a) {
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a = BigInt(a);
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return (a >= _ZERO) ? a : -a;
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}
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/**
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* Returns the bitlength of a number
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*
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* @param {bigint} a
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* @returns {number} - the bit length
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*/
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function bitLength(a) {
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if (a === _ONE)
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return 1;
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let bits = 1;
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do {
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bits++;
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} while ((a >>= _ONE) > _ONE);
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return bits;
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}
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/**
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* @typedef {Object} egcdReturn A triple (g, x, y), such that ax + by = g = gcd(a, b).
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* @property {bigint} g
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* @property {bigint} x
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* @property {bigint} y
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*/
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/**
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* An iterative implementation of the extended euclidean algorithm or extended greatest common divisor algorithm.
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* Take positive integers a, b as input, and return a triple (g, x, y), such that ax + by = g = gcd(a, b).
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*
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* @param {number|bigint} a
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* @param {number|bigint} b
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*
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* @returns {egcdReturn}
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*/
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function eGcd(a, b) {
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a = BigInt(a);
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b = BigInt(b);
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let x = _ZERO;
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let y = _ONE;
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let u = _ONE;
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let v = _ZERO;
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while (a !== _ZERO) {
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let q = b / a;
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let r = b % a;
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let m = x - (u * q);
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let n = y - (v * q);
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b = a;
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a = r;
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x = u;
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y = v;
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u = m;
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v = n;
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}
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return {
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b: b,
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x: x,
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y: y
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};
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}
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/**
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* Greatest-common divisor of two integers based on the iterative binary algorithm.
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*
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* @param {number|bigint} a
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* @param {number|bigint} b
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*
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* @returns {bigint} The greatest common divisor of a and b
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*/
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function gcd(a, b) {
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a = abs(a);
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b = abs(b);
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let shift = _ZERO;
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while (!((a | b) & _ONE)) {
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a >>= _ONE;
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b >>= _ONE;
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shift++;
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}
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while (!(a & _ONE)) a >>= _ONE;
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do {
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while (!(b & _ONE)) b >>= _ONE;
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if (a > b) {
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let x = a;
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a = b;
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b = x;
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}
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b -= a;
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} while (b);
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// rescale
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return a << shift;
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}
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/**
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* The test first tries if any of the first 250 small primes are a factor of the input number and then passes several
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* iterations of Miller-Rabin Probabilistic Primality Test (FIPS 186-4 C.3.1)
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*
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* @param {bigint} w An integer to be tested for primality
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* @param {number} iterations The number of iterations for the primality test. The value shall be consistent with Table C.1, C.2 or C.3
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*
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* @return {Promise} A promise that resolves to a boolean that is either true (a probably prime number) or false (definitely composite)
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*/
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async function isProbablyPrime(w, iterations = 16) {
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{ // Node.js
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if (_useWorkers) {
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const { Worker } = require('worker_threads');
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return new Promise((resolve, reject) => {
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let worker = new Worker(__filename);
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worker.on('message', (data) => {
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worker.terminate();
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resolve(data.isPrime);
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});
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worker.on('error', reject);
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worker.postMessage({
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'rnd': w,
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'iterations': iterations,
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'id': 0
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});
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});
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} else {
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return new Promise((resolve) => {
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resolve(_isProbablyPrime(w, iterations));
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});
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}
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}
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}
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/**
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* The least common multiple computed as abs(a*b)/gcd(a,b)
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* @param {number|bigint} a
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* @param {number|bigint} b
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*
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* @returns {bigint} The least common multiple of a and b
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*/
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function lcm(a, b) {
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a = BigInt(a);
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b = BigInt(b);
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return abs(a * b) / gcd(a, b);
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}
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/**
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* Modular inverse.
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*
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* @param {number|bigint} a The number to find an inverse for
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* @param {number|bigint} n The modulo
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*
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* @returns {bigint} the inverse modulo n
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*/
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function modInv(a, n) {
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let egcd = eGcd(toZn(a,n), n);
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if (egcd.b !== _ONE) {
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return null; // modular inverse does not exist
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} else {
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return toZn(egcd.x, n);
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}
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}
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/**
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* Modular exponentiation a**b mod n
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* @param {number|bigint} a base
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* @param {number|bigint} b exponent
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* @param {number|bigint} n modulo
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*
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* @returns {bigint} a**b mod n
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*/
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function modPow(a, b, n) {
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// See Knuth, volume 2, section 4.6.3.
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n = BigInt(n);
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a = toZn(a, n);
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b = BigInt(b);
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if (b < _ZERO) {
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return modInv(modPow(a, abs(b), n), n);
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}
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let result = _ONE;
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let x = a;
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while (b > 0) {
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var leastSignificantBit = b % _TWO;
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b = b / _TWO;
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if (leastSignificantBit == _ONE) {
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result = result * x;
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result = result % n;
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}
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x = x * x;
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x = x % n;
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}
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return result;
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}
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/**
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* A probably-prime (Miller-Rabin), cryptographically-secure, random-number generator.
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* The browser version uses web workers to parallelise prime look up. Therefore, it does not lock the UI
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* main process, and it can be much faster (if several cores or cpu are available).
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* The node version can also use worker_threads if they are available (enabled by default with Node 11 and
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* and can be enabled at runtime executing node --experimental-worker with node >=10.5.0).
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*
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* @param {number} bitLength The required bit length for the generated prime
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* @param {number} iterations The number of iterations for the Miller-Rabin Probabilistic Primality Test
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*
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* @returns {Promise} A promise that resolves to a bigint probable prime of bitLength bits
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*/
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function prime(bitLength, iterations = 16) {
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if (!_useWorkers) {
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let rnd = _ZERO;
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do {
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rnd = fromBuffer(randBytesSync(bitLength / 8, true));
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} while (!_isProbablyPrime(rnd, iterations));
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return new Promise((resolve) => { resolve(rnd); });
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}
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return new Promise((resolve) => {
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let workerList = [];
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const _onmessage = (msg, newWorker) => {
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if (msg.isPrime) {
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// if a prime number has been found, stop all the workers, and return it
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for (let j = 0; j < workerList.length; j++) {
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workerList[j].terminate();
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}
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while (workerList.length) {
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workerList.pop();
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}
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resolve(msg.value);
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} else { // if a composite is found, make the worker test another random number
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let buf = randBits(bitLength, true);
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let rnd = fromBuffer(buf);
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try {
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newWorker.postMessage({
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'rnd': rnd,
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'iterations': iterations,
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'id': msg.id
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});
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} catch (error) {
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// The worker has already terminated. There is nothing to handle here
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}
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}
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};
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{ // Node.js
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const { cpus } = require('os');
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const { Worker } = require('worker_threads');
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for (let i = 0; i < cpus().length; i++) {
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let newWorker = new Worker(__filename);
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newWorker.on('message', (msg) => _onmessage(msg, newWorker));
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workerList.push(newWorker);
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}
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}
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for (let i = 0; i < workerList.length; i++) {
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let buf = randBits(bitLength, true);
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let rnd = fromBuffer(buf);
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workerList[i].postMessage({
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'rnd': rnd,
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'iterations': iterations,
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'id': i
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});
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}
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});
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}
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/**
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* Returns a cryptographically secure random integer between [min,max]
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* @param {bigint} max Returned value will be <= max
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* @param {bigint} min Returned value will be >= min
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*
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* @returns {bigint} A cryptographically secure random bigint between [min,max]
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*/
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function randBetween(max, min = _ONE) {
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if (max <= min) throw new Error('max must be > min');
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const interval = max - min;
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let bitLen = bitLength(interval);
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let rnd;
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do {
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let buf = randBits(bitLen);
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rnd = fromBuffer(buf);
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} while (rnd > interval);
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return rnd + min;
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}
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/**
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* Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
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*
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* @param {number} bitLength The desired number of random bits
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* @param {boolean} forceLength If we want to force the output to have a specific bit length. It basically forces the msb to be 1
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*
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* @returns {Buffer|Uint8Array} A Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bits
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*/
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function randBits(bitLength, forceLength = false) {
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const byteLength = Math.ceil(bitLength / 8);
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let rndBytes = randBytesSync(byteLength, false);
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// Fill with 0's the extra birs
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rndBytes[0] = rndBytes[0] & (2 ** (bitLength % 8) - 1);
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if (forceLength) {
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let mask = (bitLength % 8) ? 2 ** ((bitLength % 8) - 1) : 128;
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rndBytes[0] = rndBytes[0] | mask;
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}
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return rndBytes;
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}
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/**
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* Secure random bytes for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
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*
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* @param {number} byteLength The desired number of random bytes
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* @param {boolean} forceLength If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1
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*
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* @returns {Promise} A promise that resolves to a Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bytes
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*/
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function randBytes(byteLength, forceLength = false) {
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let buf;
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{ // node
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const crypto = require('crypto');
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buf = Buffer.alloc(byteLength);
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return crypto.randomFill(buf, function (resolve) {
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// If fixed length is required we put the first bit to 1 -> to get the necessary bitLength
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if (forceLength)
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buf[0] = buf[0] | 128;
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resolve(buf);
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});
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}
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}
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/**
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* Secure random bytes for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
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*
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* @param {number} byteLength The desired number of random bytes
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* @param {boolean} forceLength If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1
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*
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* @returns {Buffer|Uint8Array} A Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bytes
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*/
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function randBytesSync(byteLength, forceLength = false) {
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let buf;
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{ // node
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const crypto = require('crypto');
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buf = Buffer.alloc(byteLength);
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crypto.randomFillSync(buf);
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}
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// If fixed length is required we put the first bit to 1 -> to get the necessary bitLength
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if (forceLength)
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buf[0] = buf[0] | 128;
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return buf;
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}
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/**
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* Finds the smallest positive element that is congruent to a in modulo n
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* @param {number|bigint} a An integer
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* @param {number|bigint} n The modulo
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*
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* @returns {bigint} The smallest positive representation of a in modulo n
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*/
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function toZn(a, n) {
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n = BigInt(n);
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a = BigInt(a) % n;
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return (a < 0) ? a + n : a;
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}
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/* HELPER FUNCTIONS */
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function fromBuffer(buf) {
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let ret = _ZERO;
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for (let i of buf.values()) {
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let bi = BigInt(i);
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ret = (ret << BigInt(8)) + bi;
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}
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return ret;
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}
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function _isProbablyPrime(w, iterations = 16) {
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/*
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PREFILTERING. Even values but 2 are not primes, so don't test.
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1 is not a prime and the M-R algorithm needs w>1.
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*/
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if (w === _TWO)
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return true;
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else if ((w & _ONE) === _ZERO || w === _ONE)
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return false;
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/*
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Test if any of the first 250 small primes are a factor of w. 2 is not tested because it was already tested above.
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*/
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const firstPrimes = [
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3,
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5,
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7,
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11,
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13,
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17,
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19,
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23,
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29,
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31,
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37,
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41,
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43,
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47,
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53,
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59,
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61,
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67,
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71,
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73,
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79,
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83,
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89,
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97,
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101,
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103,
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107,
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109,
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113,
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127,
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131,
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137,
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139,
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149,
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151,
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157,
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163,
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167,
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173,
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179,
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181,
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191,
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193,
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197,
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199,
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211,
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223,
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227,
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229,
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233,
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239,
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241,
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251,
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257,
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263,
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269,
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271,
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277,
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281,
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283,
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293,
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307,
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311,
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313,
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317,
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331,
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337,
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347,
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349,
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353,
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359,
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367,
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373,
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379,
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383,
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389,
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397,
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401,
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409,
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419,
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421,
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431,
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433,
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439,
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443,
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449,
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457,
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461,
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463,
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467,
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479,
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||
487,
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491,
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499,
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503,
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509,
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521,
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523,
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541,
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547,
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557,
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563,
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||
569,
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571,
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||
577,
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||
587,
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593,
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||
599,
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||
601,
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||
607,
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||
613,
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||
617,
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||
619,
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631,
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||
641,
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||
643,
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||
647,
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||
653,
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||
659,
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||
661,
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||
673,
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||
677,
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||
683,
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||
691,
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||
701,
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709,
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719,
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727,
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||
733,
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739,
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||
743,
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751,
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||
757,
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||
761,
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769,
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||
773,
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||
787,
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797,
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809,
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||
811,
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||
821,
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||
823,
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827,
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||
829,
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839,
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853,
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||
857,
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||
859,
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||
863,
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877,
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881,
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||
883,
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887,
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907,
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911,
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919,
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929,
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937,
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941,
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947,
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953,
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967,
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971,
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977,
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983,
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991,
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997,
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1009,
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1013,
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1019,
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1021,
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1031,
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1033,
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1039,
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1049,
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1051,
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1061,
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1063,
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1069,
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1087,
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1091,
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1093,
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1097,
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1103,
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1109,
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1117,
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1123,
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1129,
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1151,
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1153,
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1163,
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1171,
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1181,
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||
1187,
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1193,
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||
1201,
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||
1213,
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1217,
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1223,
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||
1229,
|
||
1231,
|
||
1237,
|
||
1249,
|
||
1259,
|
||
1277,
|
||
1279,
|
||
1283,
|
||
1289,
|
||
1291,
|
||
1297,
|
||
1301,
|
||
1303,
|
||
1307,
|
||
1319,
|
||
1321,
|
||
1327,
|
||
1361,
|
||
1367,
|
||
1373,
|
||
1381,
|
||
1399,
|
||
1409,
|
||
1423,
|
||
1427,
|
||
1429,
|
||
1433,
|
||
1439,
|
||
1447,
|
||
1451,
|
||
1453,
|
||
1459,
|
||
1471,
|
||
1481,
|
||
1483,
|
||
1487,
|
||
1489,
|
||
1493,
|
||
1499,
|
||
1511,
|
||
1523,
|
||
1531,
|
||
1543,
|
||
1549,
|
||
1553,
|
||
1559,
|
||
1567,
|
||
1571,
|
||
1579,
|
||
1583,
|
||
1597,
|
||
];
|
||
for (let i = 0; i < firstPrimes.length && (BigInt(firstPrimes[i]) <= w); i++) {
|
||
const p = BigInt(firstPrimes[i]);
|
||
if (w === p)
|
||
return true;
|
||
else if (w % p === _ZERO)
|
||
return false;
|
||
}
|
||
|
||
/*
|
||
1. Let a be the largest integer such that 2**a divides w−1.
|
||
2. m = (w−1) / 2**a.
|
||
3. wlen = len (w).
|
||
4. For i = 1 to iterations do
|
||
4.1 Obtain a string b of wlen bits from an RBG.
|
||
Comment: Ensure that 1 < b < w−1.
|
||
4.2 If ((b ≤ 1) or (b ≥ w−1)), then go to step 4.1.
|
||
4.3 z = b**m mod w.
|
||
4.4 If ((z = 1) or (z = w − 1)), then go to step 4.7.
|
||
4.5 For j = 1 to a − 1 do.
|
||
4.5.1 z = z**2 mod w.
|
||
4.5.2 If (z = w−1), then go to step 4.7.
|
||
4.5.3 If (z = 1), then go to step 4.6.
|
||
4.6 Return COMPOSITE.
|
||
4.7 Continue.
|
||
Comment: Increment i for the do-loop in step 4.
|
||
5. Return PROBABLY PRIME.
|
||
*/
|
||
let a = _ZERO, d = w - _ONE;
|
||
while (d % _TWO === _ZERO) {
|
||
d /= _TWO;
|
||
++a;
|
||
}
|
||
|
||
let m = (w - _ONE) / (_TWO ** a);
|
||
|
||
loop: do {
|
||
let b = randBetween(w - _ONE, _TWO);
|
||
let z = modPow(b, m, w);
|
||
if (z === _ONE || z === w - _ONE)
|
||
continue;
|
||
|
||
for (let j = 1; j < a; j++) {
|
||
z = modPow(z, _TWO, w);
|
||
if (z === w - _ONE)
|
||
continue loop;
|
||
if (z === _ONE)
|
||
break;
|
||
}
|
||
return false;
|
||
} while (--iterations);
|
||
|
||
return true;
|
||
}
|
||
|
||
|
||
let _useWorkers = true; // The following is just to check wheter Node.js can use workers
|
||
{ // Node.js
|
||
_useWorkers = (function _workers() {
|
||
try {
|
||
require.resolve('worker_threads');
|
||
return true;
|
||
} catch (e) {
|
||
console.log(`[bigint-crypto-utils] WARNING:
|
||
This node version doesn't support worker_threads. You should enable them in order to greatly speedup the generation of big prime numbers.
|
||
· With Node 11 it is enabled by default (consider upgrading).
|
||
· With Node 10, starting with 10.5.0, you can enable worker_threads at runtime executing node --experimental-worker `);
|
||
return false;
|
||
}
|
||
})();
|
||
}
|
||
|
||
|
||
|
||
if (_useWorkers) { // node.js with support for workers
|
||
const { parentPort, isMainThread } = require('worker_threads');
|
||
if (!isMainThread) { // worker
|
||
parentPort.on('message', function (data) { // Let's start once we are called
|
||
// data = {rnd: <bigint>, iterations: <number>}
|
||
const isPrime = _isProbablyPrime(data.rnd, data.iterations);
|
||
parentPort.postMessage({
|
||
'isPrime': isPrime,
|
||
'value': data.rnd,
|
||
'id': data.id
|
||
});
|
||
});
|
||
}
|
||
}
|
||
|
||
exports.abs = abs;
|
||
exports.bitLength = bitLength;
|
||
exports.eGcd = eGcd;
|
||
exports.gcd = gcd;
|
||
exports.isProbablyPrime = isProbablyPrime;
|
||
exports.lcm = lcm;
|
||
exports.modInv = modInv;
|
||
exports.modPow = modPow;
|
||
exports.prime = prime;
|
||
exports.randBetween = randBetween;
|
||
exports.randBits = randBits;
|
||
exports.randBytes = randBytes;
|
||
exports.randBytesSync = randBytesSync;
|
||
exports.toZn = toZn;
|