rsa-compat.js

JavaScript RSA utils that work on Windows, Mac, and Linux with or without C compiler

In order to provide a module that "just works" everywhere, we mix and match methods from node.js core, ursa, forge, and others.

(in the future we'd like to provide the same API to the browser)

Examples

Generate an RSA Keypair:

var PromiseA = require('bluebird');
var RSA = PromiseA.promisify(require('rsa-compat').RSA);

var bitlen = 1024;
var exp = 65537;
var options = { public: true, pem: true, internal: true };

RSA.generateKeypair(bitlen, exp, options).then(function (keypair) {
  console.log(keypair);
});

console.log(keypair):

// http://crypto.stackexchange.com/questions/6593/what-data-is-saved-in-rsa-private-key

{ publicKeyPem: '/*base64 pem-encoded string*/'
, privateKeyPem: '/*base64 pem-encoded string*/'
, privateKeyJwk: {
    kty: "RSA"
  , n: '/*base64 modulus n = pq*/'
  , e: '/*base64 exponent (usually 65537)*/'
  , d: '/*base64 private exponent (d = e^−1 (mod ϕ(n))/'
  , p: '/*base64 first prime*/'
  , q: /*base64 second prime*/
  , dp: /*base64 first exponent for Chinese remainder theorem (dP = d (mod p−1))*/
  , dq: /*base64 Second exponent, used for CRT (dQ = d (mod q−1))/
  , qi: /*base64 Coefficient, used for CRT (qinv = q^−1 (mod p))*/
  }
, publicKeyJwk: {
    kty: "RSA"
  , n: /*base64 modulus n = pq*/
  , e: /base64 exponent (usually 65537)*/
  }
, _ursa: /*undefined or intermediate ursa object*/
, _forge: /*undefined or intermediate forge object*/
}

// NOTE: this object is JSON safe as _ursa and _forge will be ignored

API

• RSA.generateKeypair(bitlen, exp, options, cb)
• RSA.importPemPrivateKey(privatePem)

RSA.generateKeypair(bitlen, exp, options, cb)

Create a private keypair and export it as PEM, JWK, and/or internal formats

RSA.generateKeypair(null, null, null, function (keypair) { /*...*/ });

RSA.generateKeypair(1024, 65537, { pem: false, public: false, internal: false }, function (keypair) { /*...*/ });

bitlen: 1024 (default), 2048, or 4096

exp: 65537 (default)

options:

{ public: false       // export public keys
, pem: false          // export pems
, jwk: true           // export jwks
, internal: false     // preserve internal intermediate formats (_ursa, _forge)
, thumbprint: false   // JWK sha256 thumbprint
, fingerprint: false  // NOT IMPLEMENTED (RSA key fingerprint)
}

RSA.import(keypair, options, cb)

Import a private key or public key as PEM, JWK, and/or internal formats

rsa:

{ publicKeyPem: '...'
, privateKeyPem: '...'
, privateKeyJwk: { /*...*/ }
, publicKeyJwk: { /*...*/ }
, _ursa: '[Object object]'
, _forge: '[Object object]'
}

options:

// same as above, except the following are also added
{ private: true   // export private key
                  // (as opposed to using a private key
                  // solely to export the public key)
}

Other

(the code is there, but they aren't exposed yet)

• toStandardB64(certbuf.toString('base64'))
• thumbprint(publicPem)
• generateCsr(privateKeyPem, ['example.com'])

    cert = toStandardB64(certbuf.toString('base64'))
    cert=cert.match(/.{1,64}/g).join('\n');
    return '-----BEGIN CERTIFICATE-----\n'+cert+'\n-----END CERTIFICATE-----';