native-crypto/lib/rsa.js

native-crypto ===

'use strict';
const publicEncrypt = require('public-encrypt');
const debug = require('debug')('native-crypto:rsa');
const RSA_PKCS1_OAEP_PADDING = 4;
const jwk2pem = require('jwk-to-pem');
var checked = false;
const subtle = global.crypto && global.crypto.subtle;
const PUB_EXPONENT = new Buffer([0x01, 0x00, 0x01]);
function checkNative() {
  if (global.process && !global.process.browser) {
    return Promise.resolve(false);
  }
  if (!subtle || !subtle.importKey || !subtle.encrypt || !subtle.decrypt) {
    return Promise.resolve(false);
  }


  if (checked) {
    return checked;
  }

  let prom = subtle.generateKey({
    name: 'RSA-OAEP',
    modulusLength: 1024,
    publicExponent: PUB_EXPONENT,
    hash: {name: 'SHA-1'}},
    false,
    ['encrypt', 'decrypt']
  ).then(keyPair=>{
    return subtle.encrypt({name: 'RSA-OAEP'}, keyPair.publicKey, PUB_EXPONENT).then(cypher=>subtle.decrypt({name: 'RSA-OAEP'}, keyPair.privateKey, cypher));

  }).then(result=>{
    if (new Buffer(result).toString('hex') === '010001') {
      debug(`has working rsa encryption`);
      return true;
    }
    debug('does not match');
    return false;
  }).catch(e=>{
    debug(`does not have working rsa encryption`);
    return false;
  });
  checked = prom;
  return prom;
}

exports.encrypt = encrypt;

function encrypt(key, data) {
  return checkNative().then(response=>{
    if (response) {
      return subtle.importKey('jwk', key, {
        name: 'RSA-OAEP',
        hash: {name: 'SHA-1'}
      }, false, ['encrypt']).then(key => subtle.encrypt({
        name: 'RSA-OAEP'
      }, key, data)).then(resp=>new Buffer(resp));
    } else {
      return publicEncrypt.publicEncrypt(jwk2pem(key), data);
    }
  });
}
exports.decrypt = decrypt;

function decrypt(key, data) {
  return checkNative().then(response=>{
    if (response) {
      return subtle.importKey('jwk', key, {
        name: 'RSA-OAEP',
        hash: {name: 'SHA-1'}
      }, false, ['decrypt']).then(key => subtle.decrypt({
        name: 'RSA-OAEP'
      }, key, data)).then(resp=>new Buffer(resp));
    } else {
      return publicEncrypt.privateDecrypt(jwk2pem(key, {
        private: true
      }), data);
    }
  });
}