bigint-crypto-utils/lib/index.browser.mod.js

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/**
* Absolute value. abs(a)==a if a>=0. abs(a)==-a if a<0
*
* @param {number|bigint} a
*
* @returns {bigint} the absolute value of a
*/
function abs (a) {
a = BigInt(a)
return (a >= 0n) ? a : -a
}
/**
* Returns the bitlength of a number
*
* @param {number|bigint} a
* @returns {number} - the bit length
*/
function bitLength (a) {
a = BigInt(a)
if (a === 1n) { return 1 }
let bits = 1
do {
bits++
} while ((a >>= 1n) > 1n)
return bits
}
/**
* @typedef {Object} egcdReturn A triple (g, x, y), such that ax + by = g = gcd(a, b).
* @property {bigint} g
* @property {bigint} x
* @property {bigint} y
*/
/**
* An iterative implementation of the extended euclidean algorithm or extended greatest common divisor algorithm.
* Take positive integers a, b as input, and return a triple (g, x, y), such that ax + by = g = gcd(a, b).
*
* @param {number|bigint} a
* @param {number|bigint} b
*
* @returns {egcdReturn} A triple (g, x, y), such that ax + by = g = gcd(a, b).
*/
function eGcd (a, b) {
a = BigInt(a)
b = BigInt(b)
if (a <= 0n | b <= 0n) throw new RangeError('a and b MUST be > 0') // a and b MUST be positive
let x = 0n
let y = 1n
let u = 1n
let v = 0n
while (a !== 0n) {
const q = b / a
const r = b % a
const m = x - (u * q)
const n = y - (v * q)
b = a
a = r
x = u
y = v
u = m
v = n
}
return {
g: b,
x: x,
y: y
}
}
/**
* Greatest-common divisor of two integers based on the iterative binary algorithm.
*
* @param {number|bigint} a
* @param {number|bigint} b
*
* @returns {bigint} The greatest common divisor of a and b
*/
function gcd (a, b) {
a = abs(a)
b = abs(b)
if (a === 0n) { return b } else if (b === 0n) { return a }
let shift = 0n
while (!((a | b) & 1n)) {
a >>= 1n
b >>= 1n
shift++
}
while (!(a & 1n)) a >>= 1n
do {
while (!(b & 1n)) b >>= 1n
if (a > b) {
const x = a
a = b
b = x
}
b -= a
} while (b)
// rescale
return a << shift
}
/**
* The least common multiple computed as abs(a*b)/gcd(a,b)
* @param {number|bigint} a
* @param {number|bigint} b
*
* @returns {bigint} The least common multiple of a and b
*/
function lcm (a, b) {
a = BigInt(a)
b = BigInt(b)
if (a === 0n && b === 0n) return BigInt(0)
return abs(a * b) / gcd(a, b)
}
/**
* Maximum. max(a,b)==a if a>=b. max(a,b)==b if a<=b
*
* @param {number|bigint} a
* @param {number|bigint} b
*
* @returns {bigint} maximum of numbers a and b
*/
function max (a, b) {
a = BigInt(a)
b = BigInt(b)
return (a >= b) ? a : b
}
/**
* Minimum. min(a,b)==b if a>=b. min(a,b)==a if a<=b
*
* @param {number|bigint} a
* @param {number|bigint} b
*
* @returns {bigint} minimum of numbers a and b
*/
function min (a, b) {
a = BigInt(a)
b = BigInt(b)
return (a >= b) ? b : a
}
/**
* Modular inverse.
*
* @param {number|bigint} a The number to find an inverse for
* @param {number|bigint} n The modulo
*
* @returns {bigint|NaN} the inverse modulo n or NaN if it does not exist
*/
function modInv (a, n) {
try {
const egcd = eGcd(toZn(a, n), n)
if (egcd.g !== 1n) {
return NaN // modular inverse does not exist
} else {
return toZn(egcd.x, n)
}
} catch (error) {
return NaN
}
}
/**
* Modular exponentiation b**e mod n. Currently using the right-to-left binary method
*
* @param {number|bigint} b base
* @param {number|bigint} e exponent
* @param {number|bigint} n modulo
*
* @returns {bigint} b**e mod n
*/
function modPow (b, e, n) {
n = BigInt(n)
if (n === 0n) { return NaN } else if (n === 1n) { return BigInt(0) }
b = toZn(b, n)
e = BigInt(e)
if (e < 0n) {
return modInv(modPow(b, abs(e), n), n)
}
let r = 1n
while (e > 0) {
if ((e % 2n) === 1n) {
r = (r * b) % n
}
e = e / 2n
b = b ** 2n % n
}
return r
}
/**
* Finds the smallest positive element that is congruent to a in modulo n
* @param {number|bigint} a An integer
* @param {number|bigint} n The modulo
*
* @returns {bigint} The smallest positive representation of a in modulo n
*/
function toZn (a, n) {
n = BigInt(n)
if (n <= 0) { return NaN }
a = BigInt(a) % n
return (a < 0) ? a + n : a
}
/**
* The test first tries if any of the first 250 small primes are a factor of the input number and then passes several
* iterations of Miller-Rabin Probabilistic Primality Test (FIPS 186-4 C.3.1)
*
* @param {number | bigint} w A positive integer to be tested for primality
* @param {number} [iterations = 16] The number of iterations for the primality test. The value shall be consistent with Table C.1, C.2 or C.3
* @param {boolean} [disableWorkers = false] Disable the use of workers for the primality test
*
* @throws {RangeError} w MUST be >= 0
*
* @returns {Promise<boolean>} A promise that resolves to a boolean that is either true (a probably prime number) or false (definitely composite)
*/
function isProbablyPrime (w, iterations = 16, disableWorkers = false) {
if (typeof w === 'number') {
w = BigInt(w)
}
if (w < 0) throw RangeError('w MUST be >= 0')
/* eslint-disable no-lone-blocks */
{ // browser
return new Promise((resolve, reject) => {
const worker = new Worker(_isProbablyPrimeWorkerUrl())
worker.onmessage = (event) => {
worker.terminate()
resolve(event.data.isPrime)
}
worker.onmessageerror = (event) => {
reject(event)
}
worker.postMessage({
rnd: w,
iterations: iterations,
id: 0
})
})
}
/* eslint-enable no-lone-blocks */
}
/**
* A probably-prime (Miller-Rabin), cryptographically-secure, random-number generator.
* The browser version uses web workers to parallelise prime look up. Therefore, it does not lock the UI
* main process, and it can be much faster (if several cores or cpu are available).
* The node version can also use worker_threads if they are available (enabled by default with Node 11 and
* and can be enabled at runtime executing node --experimental-worker with node >=10.5.0).
*
* @param {number} bitLength The required bit length for the generated prime
* @param {number} [iterations = 16] The number of iterations for the Miller-Rabin Probabilistic Primality Test
*
* @throws {RangeError} bitLength MUST be > 0
*
* @returns {Promise<bigint>} A promise that resolves to a bigint probable prime of bitLength bits.
*/
function prime (bitLength, iterations = 16) {
if (bitLength < 1) throw new RangeError('bitLength MUST be > 0')
/* istanbul ignore if */
if (!_useWorkers) { // If there is no support for workers
let rnd = 0n
do {
rnd = fromBuffer(randBitsSync(bitLength, true))
} while (!_isProbablyPrime(rnd, iterations))
return new Promise((resolve) => { resolve(rnd) })
}
return new Promise((resolve) => {
const workerList = []
const _onmessage = (msg, newWorker) => {
if (msg.isPrime) {
// if a prime number has been found, stop all the workers, and return it
for (let j = 0; j < workerList.length; j++) {
workerList[j].terminate()
}
while (workerList.length) {
workerList.pop()
}
resolve(msg.value)
} else { // if a composite is found, make the worker test another random number
const buf = randBitsSync(bitLength, true)
const rnd = fromBuffer(buf)
try {
newWorker.postMessage({
rnd: rnd,
iterations: iterations,
id: msg.id
})
} catch (error) {
// The worker has already terminated. There is nothing to handle here
}
}
}
/* eslint-disable no-lone-blocks */
{ // browser
const workerURL = _isProbablyPrimeWorkerUrl()
for (let i = 0; i < self.navigator.hardwareConcurrency - 1; i++) {
const newWorker = new Worker(workerURL)
newWorker.onmessage = (event) => _onmessage(event.data, newWorker)
workerList.push(newWorker)
}
}
/* eslint-enable no-lone-blocks */
for (let i = 0; i < workerList.length; i++) {
randBits(bitLength, true).then(function (buf) {
const rnd = fromBuffer(buf)
workerList[i].postMessage({
rnd: rnd,
iterations: iterations,
id: i
})
})
}
})
}
/**
* A probably-prime (Miller-Rabin), cryptographically-secure, random-number generator.
* The sync version is NOT RECOMMENDED since it won't use workers and thus it'll be slower and may freeze thw window in browser's javascript. Please consider using prime() instead.
*
* @param {number} bitLength The required bit length for the generated prime
* @param {number} [iterations = 16] The number of iterations for the Miller-Rabin Probabilistic Primality Test
*
* @throws {RangeError} bitLength MUST be > 0
*
* @returns {bigint} A bigint probable prime of bitLength bits.
*/
function primeSync (bitLength, iterations = 16) {
if (bitLength < 1) throw new RangeError('bitLength MUST be > 0')
let rnd = 0n
do {
rnd = fromBuffer(randBitsSync(bitLength, true))
} while (!_isProbablyPrime(rnd, iterations))
return rnd
}
/**
* Returns a cryptographically secure random integer between [min,max]. Both numbers must be >=0
* @param {bigint} max Returned value will be <= max
* @param {bigint} [min = BigInt(1)] Returned value will be >= min
*
* @throws {RangeError} Arguments MUST be: max > 0 && min >=0 && max > min
*
* @returns {bigint} A cryptographically secure random bigint between [min,max]
*/
function randBetween (max, min = 1n) {
if (max <= 0n || min < 0n || max <= min) throw new RangeError('Arguments MUST be: max > 0 && min >=0 && max > min')
const interval = max - min
const bitLen = bitLength(interval)
let rnd
do {
const buf = randBitsSync(bitLen)
rnd = fromBuffer(buf)
} while (rnd > interval)
return rnd + min
}
/**
* Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
*
* @param {number} bitLength The desired number of random bits
* @param {boolean} [forceLength = false] If we want to force the output to have a specific bit length. It basically forces the msb to be 1
*
* @throws {RangeError} bitLength MUST be > 0
*
* @returns {Promise<Buffer | Uint8Array>} A Promise that resolves to a Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bits
*/
function randBits (bitLength, forceLength = false) {
if (bitLength < 1) throw new RangeError('bitLength MUST be > 0')
const byteLength = Math.ceil(bitLength / 8)
const bitLengthMod8 = bitLength % 8
return new Promise((resolve) => {
randBytes(byteLength, false).then(function (rndBytes) {
if (bitLengthMod8) {
// Fill with 0's the extra bits
rndBytes[0] = rndBytes[0] & (2 ** bitLengthMod8 - 1)
}
if (forceLength) {
const mask = bitLengthMod8 ? 2 ** (bitLengthMod8 - 1) : 128
rndBytes[0] = rndBytes[0] | mask
}
resolve(rndBytes)
})
})
}
/**
* Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
* @param {number} bitLength The desired number of random bits
* @param {boolean} [forceLength = false] If we want to force the output to have a specific bit length. It basically forces the msb to be 1
*
* @throws {RangeError} bitLength MUST be > 0
*
* @returns {Buffer | Uint8Array} A Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bits
*/
function randBitsSync (bitLength, forceLength = false) {
if (bitLength < 1) throw new RangeError('bitLength MUST be > 0')
const byteLength = Math.ceil(bitLength / 8)
const rndBytes = randBytesSync(byteLength, false)
const bitLengthMod8 = bitLength % 8
if (bitLengthMod8) {
// Fill with 0's the extra bits
rndBytes[0] = rndBytes[0] & (2 ** bitLengthMod8 - 1)
}
if (forceLength) {
const mask = bitLengthMod8 ? 2 ** (bitLengthMod8 - 1) : 128
rndBytes[0] = rndBytes[0] | mask
}
return rndBytes
}
/**
* Secure random bytes for both node and browsers. Node version uses crypto.randomBytes() and browser one self.crypto.getRandomValues()
*
* @param {number} byteLength The desired number of random bytes
* @param {boolean} [forceLength = false] If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1
*
* @throws {RangeError} byteLength MUST be > 0
*
* @returns {Promise<Buffer | Uint8Array>} A promise that resolves to a Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bytes
*/
function randBytes (byteLength, forceLength = false) {
if (byteLength < 1) throw new RangeError('byteLength MUST be > 0')
return new Promise(function (resolve, reject) {
/* eslint-disable no-lone-blocks */
{ // browser
const buf = new Uint8Array(byteLength)
self.crypto.getRandomValues(buf)
// If fixed length is required we put the first bit to 1 -> to get the necessary bitLength
if (forceLength) buf[0] = buf[0] | 128
resolve(buf)
}
/* eslint-enable no-lone-blocks */
})
}
/**
* Secure random bytes for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
*
* @param {number} byteLength The desired number of random bytes
* @param {boolean} [forceLength = false] If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1
*
* @throws {RangeError} byteLength MUST be > 0
*
* @returns {Buffer | Uint8Array} A Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bytes
*/
function randBytesSync (byteLength, forceLength = false) {
if (byteLength < 1) throw new RangeError('byteLength MUST be > 0')
/* eslint-disable no-lone-blocks */
{ // browser
const buf = new Uint8Array(byteLength)
self.crypto.getRandomValues(buf)
// If fixed length is required we put the first bit to 1 -> to get the necessary bitLength
if (forceLength) buf[0] = buf[0] | 128
return buf
}
/* eslint-enable no-lone-blocks */
}
/* HELPER FUNCTIONS */
function fromBuffer (buf) {
let ret = 0n
for (const i of buf.values()) {
const bi = BigInt(i)
ret = (ret << BigInt(8)) + bi
}
return ret
}
function _isProbablyPrimeWorkerUrl () {
// Let's us first add all the required functions
let workerCode = `'use strict';const ${eGcd.name}=${eGcd.toString()};const ${modInv.name}=${modInv.toString()};const ${modPow.name}=${modPow.toString()};const ${toZn.name}=${toZn.toString()};const ${randBitsSync.name}=${randBitsSync.toString()};const ${randBytesSync.name}=${randBytesSync.toString()};const ${randBetween.name}=${randBetween.toString()};const ${isProbablyPrime.name}=${_isProbablyPrime.toString()};${bitLength.toString()}${fromBuffer.toString()}`
const onmessage = async function (event) { // Let's start once we are called
// event.data = {rnd: <bigint>, iterations: <number>}
const isPrime = await isProbablyPrime(event.data.rnd, event.data.iterations)
postMessage({
isPrime: isPrime,
value: event.data.rnd,
id: event.data.id
})
}
workerCode += `onmessage = ${onmessage.toString()};`
return _workerUrl(workerCode)
}
function _workerUrl (workerCode) {
workerCode = `(() => {${workerCode}})()` // encapsulate IIFE
const _blob = new Blob([workerCode], { type: 'text/javascript' })
return window.URL.createObjectURL(_blob)
}
function _isProbablyPrime (w, iterations = 16) {
/*
PREFILTERING. Even values but 2 are not primes, so don't test.
1 is not a prime and the M-R algorithm needs w>1.
*/
if (w === 2n) return true
else if ((w & 1n) === 0n || w === 1n) return false
/*
Test if any of the first 250 small primes are a factor of w. 2 is not tested because it was already tested above.
*/
const firstPrimes = [
3n,
5n,
7n,
11n,
13n,
17n,
19n,
23n,
29n,
31n,
37n,
41n,
43n,
47n,
53n,
59n,
61n,
67n,
71n,
73n,
79n,
83n,
89n,
97n,
101n,
103n,
107n,
109n,
113n,
127n,
131n,
137n,
139n,
149n,
151n,
157n,
163n,
167n,
173n,
179n,
181n,
191n,
193n,
197n,
199n,
211n,
223n,
227n,
229n,
233n,
239n,
241n,
251n,
257n,
263n,
269n,
271n,
277n,
281n,
283n,
293n,
307n,
311n,
313n,
317n,
331n,
337n,
347n,
349n,
353n,
359n,
367n,
373n,
379n,
383n,
389n,
397n,
401n,
409n,
419n,
421n,
431n,
433n,
439n,
443n,
449n,
457n,
461n,
463n,
467n,
479n,
487n,
491n,
499n,
503n,
509n,
521n,
523n,
541n,
547n,
557n,
563n,
569n,
571n,
577n,
587n,
593n,
599n,
601n,
607n,
613n,
617n,
619n,
631n,
641n,
643n,
647n,
653n,
659n,
661n,
673n,
677n,
683n,
691n,
701n,
709n,
719n,
727n,
733n,
739n,
743n,
751n,
757n,
761n,
769n,
773n,
787n,
797n,
809n,
811n,
821n,
823n,
827n,
829n,
839n,
853n,
857n,
859n,
863n,
877n,
881n,
883n,
887n,
907n,
911n,
919n,
929n,
937n,
941n,
947n,
953n,
967n,
971n,
977n,
983n,
991n,
997n,
1009n,
1013n,
1019n,
1021n,
1031n,
1033n,
1039n,
1049n,
1051n,
1061n,
1063n,
1069n,
1087n,
1091n,
1093n,
1097n,
1103n,
1109n,
1117n,
1123n,
1129n,
1151n,
1153n,
1163n,
1171n,
1181n,
1187n,
1193n,
1201n,
1213n,
1217n,
1223n,
1229n,
1231n,
1237n,
1249n,
1259n,
1277n,
1279n,
1283n,
1289n,
1291n,
1297n,
1301n,
1303n,
1307n,
1319n,
1321n,
1327n,
1361n,
1367n,
1373n,
1381n,
1399n,
1409n,
1423n,
1427n,
1429n,
1433n,
1439n,
1447n,
1451n,
1453n,
1459n,
1471n,
1481n,
1483n,
1487n,
1489n,
1493n,
1499n,
1511n,
1523n,
1531n,
1543n,
1549n,
1553n,
1559n,
1567n,
1571n,
1579n,
1583n,
1597n
]
for (let i = 0; i < firstPrimes.length && (firstPrimes[i] <= w); i++) {
const p = firstPrimes[i]
if (w === p) return true
else if (w % p === 0n) return false
}
/*
1. Let a be the largest integer such that 2**a divides w1.
2. m = (w1) / 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 < w1.
4.2 If ((b ≤ 1) or (b ≥ w1)), 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 = w1), 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 = 0n
const d = w - 1n
let aux = d
while (aux % 2n === 0n) {
aux /= 2n
++a
}
const m = d / (2n ** a)
do {
const b = randBetween(d, 2n)
let z = modPow(b, m, w)
if (z === 1n || z === d) continue
let j = 1
while (j < a) {
z = modPow(z, 2n, w)
if (z === d) break
if (z === 1n) return false
j++
}
if (z !== d) return false
} while (--iterations)
return true
}
let _useWorkers = false // The following is just to check whether we can use workers
/* eslint-disable no-lone-blocks */
{ // Native JS
if (self.Worker) _useWorkers = true
}
export { abs, bitLength, eGcd, gcd, isProbablyPrime, lcm, max, min, modInv, modPow, prime, primeSync, randBetween, randBits, randBitsSync, randBytes, randBytesSync, toZn }