jsbn

What is jsbn?

The jsbn npm package is a library that implements big number arithmetic and RSA encryption. It is useful for cryptography and other applications that require manipulation of large integers that are beyond the native JavaScript Number limit.

What are jsbn's main functionalities?

Big Number Arithmetic

This feature allows for the addition, subtraction, multiplication, division, and modulus operations on large integers.

var BigInteger = require('jsbn').BigInteger;
var a = new BigInteger('91823918239182398123');
var b = new BigInteger('98237283728372873232');
var sum = a.add(b); // Addition
var difference = a.subtract(b); // Subtraction
var product = a.multiply(b); // Multiplication
var quotient = a.divide(b); // Division
var remainder = a.mod(b); // Modulus

RSA Encryption

This feature allows for RSA encryption and decryption, which is useful for secure data transmission.

var BigInteger = require('jsbn').BigInteger;
var RSAKey = require('jsbn').RSAKey;
var key = new RSAKey();
key.setPublic('...public exponent...', '...modulus...');
var encrypted = key.encrypt('text to encrypt');
key.setPrivate('...modulus...', '...public exponent...', '...private exponent...');
var decrypted = key.decrypt(encrypted);

Other packages similar to jsbn

bignumber.js

bignumber.js is a JavaScript library for arbitrary-precision decimal and non-decimal arithmetic. It provides similar big number arithmetic capabilities as jsbn but with a focus on decimal arithmetic and more extensive API for different mathematical operations.

node-rsa

node-rsa is a Node.js RSA library that provides similar RSA encryption and decryption functionalities as jsbn. It offers a more user-friendly API and additional features such as key generation, signing, and verification.

forge

forge is a JavaScript library that provides a wide range of cryptographic operations including big number arithmetic and RSA encryption. It is more comprehensive than jsbn, offering additional features like symmetric encryption, hashing, and TLS support.

README

jsbn: javascript big number

Tom Wu's Original Website

I felt compelled to put this on github and publish to npm. I haven't tested every other big integer library out there, but the few that I have tested in comparison to this one have not even come close in performance. I am aware of the bi module on npm, however it has been modified and I wanted to publish the original without modifications. This is jsbn and jsbn2 from Tom Wu's original website above, with the modular pattern applied to prevent global leaks and to allow for use with node.js on the server side.

usage

var BigInteger = require('jsbn');

var a = new BigInteger('91823918239182398123');
alert(a.bitLength()); // 67

API

bi.toString()

returns the base-10 number as a string

bi.negate()

returns a new BigInteger equal to the negation of bi

bi.abs

returns new BI of absolute value

bi.compareTo

bi.bitLength

bi.mod

bi.modPowInt

bi.clone

bi.intValue

bi.byteValue

bi.shortValue

bi.signum

bi.toByteArray

bi.equals

bi.min

bi.max

bi.and

bi.or

bi.xor

bi.andNot

bi.not

bi.shiftLeft

bi.shiftRight

bi.getLowestSetBit

bi.bitCount

bi.testBit

bi.setBit

bi.clearBit

bi.flipBit

bi.add

bi.subtract

bi.multiply

bi.divide

bi.remainder

bi.divideAndRemainder

bi.modPow

bi.modInverse

bi.pow

bi.gcd

bi.isProbablePrime

Changelog

v0.1.1

• fixed backwards-incompatible change in v0.1.0 where require('jsbn') != BigInteger. This patch version allows for var BigInteger = require('jsbn') or var BigInteger = require('jsbn').BigInteger.