Utils for working with cryptography using native JS (stage 3) implementation of BigInt. It includes some extra functions to work with modular arithmetics along with secure random numbers and a fast strong probable prime generator/tester (parallelised multi-threaded Miller-Rabin primality test). It can be used by any Web Browser or webview supporting BigInt and with Node.js (>=10.4.0). In the latter case, for multi-threaded primality tests, you should use Node.js 11 or enable at runtime with node --experimental-worker with Node.js >=10.5.0.
The operations supported on BigInts are not constant time. BigInt can be therefore unsuitable for use in cryptography. Many platforms provide native support for cryptography, such as Web Cryptography API or Node.js Crypto.
bigint-crypto-utils is distributed for web browsers and/or webviews supporting BigInt as an ES6 module or an IIFE file; and for Node.js (>=10.4.0), as a CJS module.
bigint-crypto-utils can be imported to your project with npm:
npm install bigint-crypto-utilsNPM installation defaults to the ES6 module for browsers and the CJS one for Node.js.
For web browsers, you can also directly download the minimised version of the IIFE file or the ES6 module from GitHub.
With node js:
const bigintCryptoUtils = require('bigint-crypto-utils');
/* Stage 3 BigInts with value 666 can be declared as BigInt('666')
or the shorter new no-so-linter-friendly syntax 666n.
Notice that you can also pass a number, e.g. BigInt(666), but it is not
recommended since values over 2**53 - 1 won't be safe but no warning will
be raised.
*/
let a = BigInt('5');
let b = BigInt('2');
let n = BigInt('19');
console.log(bigintCryptoUtils.modPow(a, b, n)); // prints 6
console.log(bigintCryptoUtils.modInv(BigInt('2'), BigInt('5'))); // prints 3
console.log(bigintCryptoUtils.modInv(BigInt('3'), BigInt('5'))); // prints 2
// Generation of a probable prime of 2048 bits
const prime = await bigintCryptoUtils.prime(2048);
// Testing if a prime is a probable prime (Miller-Rabin)
if ( await bigintCryptoUtils.isProbablyPrime(prime) )
// code if is prime
// Get a cryptographically secure random number between 1 and 2**256 bits.
const rnd = bigintCryptoUtils.randBetween(BigInt(2) ** BigInt(256));From a browser, you can just load the module in a html page as:
<script type="module">
import * as bigintCryptoUtils from 'bigint-utils-latest.browser.mod.min.js';
let a = BigInt('5');
let b = BigInt('2');
let n = BigInt('19');
console.log(bigintCryptoUtils.modPow(a, b, n)); // prints 6
console.log(bigintCryptoUtils.modInv(BigInt('2'), BigInt('5'))); // prints 3
console.log(bigintCryptoUtils.modInv(BigInt('3'), BigInt('5'))); // prints 2
(async function () {
// Generation of a probable prime of 2018 bits
const p = await bigintCryptoUtils.prime(2048);
// Testing if a prime is a probable prime (Miller-Rabin)
const isPrime = await bigintCryptoUtils.isProbablyPrime(p);
alert(p.toString() + '\nIs prime?\n' + isPrime);
// Get a cryptographically secure random number between 1 and 2**256 bits.
const rnd = bigintCryptoUtils.randBetween(BigInt(2) ** BigInt(256));
alert(rnd);
})();
</script>- abs(a) ⇒
bigint Absolute value. abs(a)==a if a>=0. abs(a)==-a if a<0
- bitLength(a) ⇒
number Returns the bitlength of a number
- eGcd(a, b) ⇒
egcdReturn 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).
- gcd(a, b) ⇒
bigint Greatest-common divisor of two integers based on the iterative binary algorithm.
- isProbablyPrime(w, iterations) ⇒
Promise 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)
- lcm(a, b) ⇒
bigint The least common multiple computed as abs(a*b)/gcd(a,b)
- modInv(a, n) ⇒
bigint Modular inverse.
- modPow(b, e, n) ⇒
bigint Modular exponentiation b**e mod n. Currently using the right-to-left binary method
- prime(bitLength, iterations) ⇒
Promise 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).
- randBetween(max, min) ⇒
bigint Returns a cryptographically secure random integer between [min,max]
- randBits(bitLength, forceLength) ⇒
Buffer|Uint8Array Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
- randBytes(byteLength, forceLength) ⇒
Promise Secure random bytes for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
- randBytesSync(byteLength, forceLength) ⇒
Buffer|Uint8Array Secure random bytes for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
- toZn(a, n) ⇒
bigint Finds the smallest positive element that is congruent to a in modulo n
- egcdReturn :
Object A triple (g, x, y), such that ax + by = g = gcd(a, b).
Absolute value. abs(a)==a if a>=0. abs(a)==-a if a<0
Kind: global function
Returns: bigint - the absolute value of a
| Param | Type |
|---|---|
| a | number | bigint |
Returns the bitlength of a number
Kind: global function
Returns: number - - the bit length
| Param | Type |
|---|---|
| a | number | bigint |
eGcd(a, b) ⇒ egcdReturn
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).
Kind: global function
Returns: egcdReturn - A triple (g, x, y), such that ax + by = g = gcd(a, b).
| Param | Type |
|---|---|
| a | number | bigint |
| b | number | bigint |
Greatest-common divisor of two integers based on the iterative binary algorithm.
Kind: global function
Returns: bigint - The greatest common divisor of a and b
| Param | Type |
|---|---|
| a | number | bigint |
| b | number | bigint |
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)
Kind: global function
Returns: Promise - A promise that resolves to a boolean that is either true (a probably prime number) or false (definitely composite)
| Param | Type | Description |
|---|---|---|
| w | number | bigint |
An integer to be tested for primality |
| iterations | number |
The number of iterations for the primality test. The value shall be consistent with Table C.1, C.2 or C.3 |
The least common multiple computed as abs(a*b)/gcd(a,b)
Kind: global function
Returns: bigint - The least common multiple of a and b
| Param | Type |
|---|---|
| a | number | bigint |
| b | number | bigint |
Modular inverse.
Kind: global function
Returns: bigint - the inverse modulo n or NaN if it does not exist
| Param | Type | Description |
|---|---|---|
| a | number | bigint |
The number to find an inverse for |
| n | number | bigint |
The modulo |
Modular exponentiation b**e mod n. Currently using the right-to-left binary method
Kind: global function
Returns: bigint - b**e mod n
| Param | Type | Description |
|---|---|---|
| b | number | bigint |
base |
| e | number | bigint |
exponent |
| n | number | bigint |
modulo |
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).
Kind: global function
Returns: Promise - A promise that resolves to a bigint probable prime of bitLength bits
| Param | Type | Description |
|---|---|---|
| bitLength | number |
The required bit length for the generated prime |
| iterations | number |
The number of iterations for the Miller-Rabin Probabilistic Primality Test |
Returns a cryptographically secure random integer between [min,max]
Kind: global function
Returns: bigint - A cryptographically secure random bigint between [min,max]
| Param | Type | Description |
|---|---|---|
| max | bigint |
Returned value will be <= max |
| min | bigint |
Returned value will be >= min |
Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
Kind: global function
Returns: Buffer | Uint8Array - A Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bits
| Param | Type | Description |
|---|---|---|
| bitLength | number |
The desired number of random bits |
| forceLength | boolean |
If we want to force the output to have a specific bit length. It basically forces the msb to be 1 |
Secure random bytes for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
Kind: global function
Returns: Promise - A promise that resolves to a Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bytes
| Param | Type | Description |
|---|---|---|
| byteLength | number |
The desired number of random bytes |
| forceLength | boolean |
If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1 |
Secure random bytes for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
Kind: global function
Returns: Buffer | Uint8Array - A Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bytes
| Param | Type | Description |
|---|---|---|
| byteLength | number |
The desired number of random bytes |
| forceLength | boolean |
If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1 |
Finds the smallest positive element that is congruent to a in modulo n
Kind: global function
Returns: bigint - The smallest positive representation of a in modulo n
| Param | Type | Description |
|---|---|---|
| a | number | bigint |
An integer |
| n | number | bigint |
The modulo |
A triple (g, x, y), such that ax + by = g = gcd(a, b).
Kind: global typedef
Properties
| Name | Type |
|---|---|
| g | bigint |
| x | bigint |
| y | bigint |