bigint-crypto-utils
Arbitrary precision modular arithmetic, cryptographically secure random numbers and strong probable prime generation/testing.
It relies on the native JS implementation of (BigInt). It can be used by any Web Browser or webview supporting BigInt and with Node.js (>=10.4.0). The bundles can be imported directly by the browser or in Angular projects, React apps, Node.js, etc.
Secure random numbers are generated using the native crypto implementation of the browsers (Web Cryptography API) or Node.js Crypto). Strong probable prime generation and testing use Miller-Rabin primality tests and are automatically sped up using parallel workers both in browsers and Node.js.
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.
Installation
bigint-crypto-utils can be imported to your project with npm
:
npm install bigint-crypto-utils
NPM installation defaults to the ES6 module for browsers and the CJS one for Node.js. For web browsers, you can also directly download the IIFE bundle or the ESM bundle from the repository.
Usage examples
Import your module as :
-
Node.js
const bigintCryptoUtils = require('bigint-crypto-utils')
...
-
JavaScript native or TypeScript project (including React and Angular JS)
import * as bigintCryptoUtils from 'bigint-crypto-utils'
...
bigint-crypto-utils
CANNOT BE POLYFILLED to suport older browsers. If you are using webpack/babel to create your production bundles, you should target only the most modern browsers. For instance, for React apps created with create-react-app
, you should edit your package.json
and modify the browserList
so that it only targets the latest browsers (supporting the latest features):
"browserslist": {
"production": [
"last 1 chrome version",
"last 1 firefox version",
"last 1 safari version"
],
"development": [
"last 1 chrome version",
"last 1 firefox version",
"last 1 safari version"
]
}
Also, notice that BigInt implementation is quite recent. In order to use it with TypeScript you will probably need to set lib
, target
and/or module
to esnext
in your project's tsconfig.json
.
-
JavaScript native browser ES module
<script type="module">
import * as bigintCryptoUtils from 'lib/index.browser.bundle.mod.js'
...
</script>
-
JavaScript native browser IIFE
<head>
...
<script src="../../lib/index.browser.bundle.iife.js"></script>
</head>
<body>
...
<script>
...
</script>
</body>
An example of usage could be:
const a = BigInt('5')
const b = BigInt('2')
const n = 19n
console.log(bigintCryptoUtils.modPow(a, b, n))
console.log(bigintCryptoUtils.modInv(2n, 5n))
console.log(bigintCryptoUtils.modInv(BigInt('3'), BigInt('5')))
console.log(bigintCryptoUtils.randBetween(2n ** 256n))
async function primeTesting () {
console.log(await bigintCryptoUtils.prime(2048))
const number = 27n
const isPrime = await bigintCryptoUtils.isProbablyPrime(number)
if (isPrime) {
console.log(`${number} is prime`)
} else {
console.log(`${number} is composite`)
}
}
primeTesting()
You can find examples in the examples folder of the repository.
API reference documentation
Functions
- 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], [disableWorkers]) ⇒
Promise.<boolean>
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)
- max(a, b) ⇒
bigint
Maximum. max(a,b)==a if a>=b. max(a,b)==b if a<=b
- min(a, b) ⇒
bigint
Minimum. min(a,b)==b if a>=b. min(a,b)==a if a<=b
- modInv(a, n) ⇒
bigint
| NaN
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.<bigint>
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).
- primeSync(bitLength, [iterations]) ⇒
bigint
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.
- randBetween(max, [min]) ⇒
bigint
Returns a cryptographically secure random integer between [min,max]. Both numbers must be >=0
- randBits(bitLength, [forceLength]) ⇒
Promise.<(Buffer|Uint8Array)>
Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
- randBitsSync(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.<(Buffer|Uint8Array)>
Secure random bytes for both node and browsers. Node version uses crypto.randomBytes() 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
Typedefs
- egcdReturn :
Object
A triple (g, x, y), such that ax + by = g = gcd(a, b).
abs(a) ⇒ bigint
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 |
bitLength(a) ⇒ number
Returns the bitlength of a number
Kind: global function
Returns: number
- - the bit length
Param | Type |
---|
a | number | bigint |
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 |
egcdReturn : Object
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 |
gcd(a, b) ⇒ 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 |
isProbablyPrime(w, [iterations], [disableWorkers]) ⇒ Promise.<boolean>
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.<boolean>
- A promise that resolves to a boolean that is either true (a probably prime number) or false (definitely composite)
Throws:
RangeError
w MUST be >= 0
Param | Type | Default | Description |
---|
w | number | bigint | | A positive integer to be tested for primality |
[iterations] | number | 16 | The number of iterations for the primality test. The value shall be consistent with Table C.1, C.2 or C.3 |
[disableWorkers] | boolean | false | Disable the use of workers for the primality test |
lcm(a, b) ⇒ bigint
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 |
max(a, b) ⇒ bigint
Maximum. max(a,b)==a if a>=b. max(a,b)==b if a<=b
Kind: global function
Returns: bigint
- maximum of numbers a and b
Param | Type |
---|
a | number | bigint |
b | number | bigint |
min(a, b) ⇒ bigint
Minimum. min(a,b)==b if a>=b. min(a,b)==a if a<=b
Kind: global function
Returns: bigint
- minimum of numbers a and b
Param | Type |
---|
a | number | bigint |
b | number | bigint |
modInv(a, n) ⇒ bigint
| NaN
Modular inverse.
Kind: global function
Returns: bigint
| NaN
- 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 |
modPow(b, e, n) ⇒ bigint
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 |
prime(bitLength, [iterations]) ⇒ Promise.<bigint>
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.<bigint>
- A promise that resolves to a bigint probable prime of bitLength bits.
Throws:
RangeError
bitLength MUST be > 0
Param | Type | Default | Description |
---|
bitLength | number | | The required bit length for the generated prime |
[iterations] | number | 16 | The number of iterations for the Miller-Rabin Probabilistic Primality Test |
primeSync(bitLength, [iterations]) ⇒ bigint
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.
Kind: global function
Returns: bigint
- A bigint probable prime of bitLength bits.
Throws:
RangeError
bitLength MUST be > 0
Param | Type | Default | Description |
---|
bitLength | number | | The required bit length for the generated prime |
[iterations] | number | 16 | The number of iterations for the Miller-Rabin Probabilistic Primality Test |
randBetween(max, [min]) ⇒ bigint
Returns a cryptographically secure random integer between [min,max]. Both numbers must be >=0
Kind: global function
Returns: bigint
- A cryptographically secure random bigint between [min,max]
Throws:
RangeError
Arguments MUST be: max > 0 && min >=0 && max > min
Param | Type | Default | Description |
---|
max | bigint | | Returned value will be <= max |
[min] | bigint | BigInt(1) | Returned value will be >= min |
randBits(bitLength, [forceLength]) ⇒ Promise.<(Buffer|Uint8Array)>
Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()
Kind: global function
Returns: Promise.<(Buffer|Uint8Array)>
- A Promise that resolves to a Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bits
Throws:
RangeError
bitLength MUST be > 0
Param | Type | Default | Description |
---|
bitLength | number | | The desired number of random bits |
[forceLength] | boolean | false | If we want to force the output to have a specific bit length. It basically forces the msb to be 1 |
randBitsSync(bitLength, [forceLength]) ⇒ Buffer
| Uint8Array
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
Throws:
RangeError
bitLength MUST be > 0
Param | Type | Default | Description |
---|
bitLength | number | | The desired number of random bits |
[forceLength] | boolean | false | If we want to force the output to have a specific bit length. It basically forces the msb to be 1 |
randBytes(byteLength, [forceLength]) ⇒ Promise.<(Buffer|Uint8Array)>
Secure random bytes for both node and browsers. Node version uses crypto.randomBytes() and browser one self.crypto.getRandomValues()
Kind: global function
Returns: Promise.<(Buffer|Uint8Array)>
- A promise that resolves to a Buffer/UInt8Array (Node.js/Browser) filled with cryptographically secure random bytes
Throws:
RangeError
byteLength MUST be > 0
Param | Type | Default | Description |
---|
byteLength | number | | The desired number of random bytes |
[forceLength] | boolean | false | If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1 |
randBytesSync(byteLength, [forceLength]) ⇒ Buffer
| Uint8Array
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
Throws:
RangeError
byteLength MUST be > 0
Param | Type | Default | Description |
---|
byteLength | number | | The desired number of random bytes |
[forceLength] | boolean | false | If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1 |
toZn(a, n) ⇒ bigint
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 |