hybrid-crypto-js/src/rsa.js

Hybrid (RSA+AES) encryption and decryption toolkit for JavaScript

// @flow
var forge = require('node-forge');
var pki = forge.pki;

type RSAProps = {
    keySize: number,
    entropy?: string | number,
};

class RSA {
    options: RSAProps;

    constructor(options: RSAProps = {}) {
        this.options = {
            keySize: 4096,
            entropy: undefined,
            ...options,
        };

        if (this.options.entropy) {
            this._entropy(this.options.entropy);
        }
    }

    /**
     * Generates RSA keypair
     *
     * @param {function} callback Function that gets called when keys are generated
     * @param {int} [keySize=4096] Integer that determines the RSA key size
     *
     * @example
     * rsa.generateKeyPair(keys => console.log(keys), 1024);
     *
     * @method
     */
    generateKeyPair(callback: Function, keySize: number): void {
        // Generate key pair using forge
        pki.rsa.generateKeyPair(
            { bits: keySize || this.options.keySize, workers: -1 },
            (err, keyPair) => {
                // Cast key pair to PEM format
                keyPair.publicKey = pki.publicKeyToPem(keyPair.publicKey);
                keyPair.privateKey = pki.privateKeyToPem(keyPair.privateKey);

                callback(keyPair);
            },
        );
    }

    /**
     * Generates RSA keypair
     *
     * @param {int} [keySize=4096] Integer that determines the RSA key size
     *
     * @example
     * rsa.generateKeyPair(1024).then(keys => console.log(keys));
     *
     * @return {Promise} Promise that gets resolved when generation is ready
     * @method
     */
    generateKeyPairAsync(keySize: number): Object {
        return new Promise<void>(resolve => {
            this.generateKeyPair(resolve, keySize);
        });
    }

    /**
     * Private function to add more entropy
     *
     * @param {String|Number} input Something random
     *
     * @method
     */
    _entropy(input: any): void {
        const inputString = String(input);
        const bytes = forge.util.encodeUtf8(inputString);

        forge.random.collect(bytes);
    }
}

module.exports = RSA;