subtle.js

/*
crypto.subtle.generateKey({
          name: 'RSA-OAEP',
          modulusLength: 2048,
          publicExponent: new Uint8Array([1, 0, 1]),
          hash: {name: 'SHA-256'}
        }, true, ['encrypt', 'decrypt'])
  .then(keypair => 
    crypto.subtle.encrypt({ name: 'RSA-OAEP', hash: {name: 'SHA-256'}}, keypair.publicKey, (new TextEncoder()).encode('lol'))
      .then(encrypted => crypto.subtle.decrypt({ name: 'RSA-OAEP', hash: {name: 'SHA-256'}}, keypair.privateKey, encrypted))
      .then(content => log((new TextDecoder()).decode(content))))
*/

/// abstract

var log = function(msg) { document.write(msg + '<br/>') }


var subtlePony = function(fnName) {
  var args = Array.prototype.slice.call(arguments).slice(1)
  if (window.crypto)
    return crypto.subtle[fnName].apply(crypto.subtle, args)
  if (window.msCrypto){
    return new Promise(function(resolve, reject) {
      var instance = msCrypto.subtle[fnName].apply(msCrypto.subtle, args)
      instance.oncomplete = function(event) { resolve(event.target.result) }
      instance.onerror = reject
    })
  }
  throw 'Your browser doesn\'t support Crypto.Subtle'
};

subtlePony('generateKey', {
  name: 'RSA-OAEP',
  modulusLength: 2048,
  publicExponent: new Uint8Array([1, 0, 1]),
  hash: {name: 'SHA-256'}
}, true, ['encrypt', 'decrypt'])
.then(function(keypair) {
  return subtlePony('encrypt', { name: 'RSA-OAEP', hash: {name: 'SHA-256'}}, keypair.publicKey, (new TextEncoder()).encode('lol'))
    .then(function(encrypted){ return subtlePony('decrypt', { name: 'RSA-OAEP', hash: {name: 'SHA-256'}}, keypair.privateKey, encrypted)})
    .then(function(content){ log((new TextDecoder()).decode(content))})
    .then(function(){ return subtlePony('exportKey', 'spki', keypair.publicKey)})
    .then(function(exportedKey){ log('-----BEGIN PUBLIC KEY-----\n' + window.btoa(String.fromCharCode.apply(null, new Uint8Array(exportedKey))) + '\n-----END PUBLIC KEY-----')})
    .then(function(){ return subtlePony('exportKey', 'pkcs8', keypair.privateKey)})
    .then(function(exportedKey) { log('-----BEGIN PRIVATE KEY-----\n' + window.btoa(String.fromCharCode.apply(null, new Uint8Array(exportedKey))) + '\n-----END PRIVATE KEY-----')})})
.then(function(){
  var pubKey = `-----BEGIN PUBLIC KEY-----
  MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtcAy8EHtaw22tpqpbe3po3imtgHuynogbW/ydFLMqRIR4Fu+9gRNfXBWDLP10FhjhJWFZjwH3RQXGDTK5zvEKMC61ajiFinDY0tegkOvjsI4x/o/jEB+UxZjS3EZbUaf77Qp7WxaEjwn7/mMW1b4rfy+gmkiebhRx5kMgEwZPWX4HzkbslsSmeHhKWf/NPHaCcvcCzOURhzNrtYlgtg48RzswPmwrxZ6+nHLyC3tnFsSHVuil9hrsup1KIG5XeEKzyjVbIMER6O3NoT35vAlV6/PeW1Rnel+oat02XKNTfb5B3QjF0n2JUHXEHyDZBl7jJ9skOizPC+YMAmJkP1/ywIDAQAB
  -----END PUBLIC KEY-----`
  var privKey = `-----BEGIN PRIVATE KEY-----
  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
  -----END PRIVATE KEY-----`

  var getRawKey = function(type, pem) {
    var pemHeader = `-----BEGIN ${type} KEY-----`;
    var pemFooter = `-----END ${type} KEY-----`;
    var pemContents = pem.substring(pemHeader.length, pem.length - pemFooter.length);
    var binaryDerString = window.atob(pemContents);
    var binaryDer = new ArrayBuffer(binaryDerString.length);
    var bufView = new Uint8Array(binaryDer);
    for (let i = 0, strLen = binaryDerString.length; i < strLen; i++) {
      bufView[i] = binaryDerString.charCodeAt(i);
    }
    return binaryDer;
  }
  subtlePony('importKey', 'spki', getRawKey('PUBLIC', pubKey),
  {
    name: 'RSA-OAEP',
    modulusLength: 2048,
    publicExponent: new Uint8Array([1, 0, 1]),
    hash: {name: 'SHA-256'}
  }, true, ['encrypt'])
    .then(function(publicKey) {
      return subtlePony('encrypt', { name: 'RSA-OAEP', hash: {name: 'SHA-256'}}, publicKey, (new TextEncoder()).encode('lol2')) })
    .then(function(encrypted) {
      return subtlePony('importKey', 'pkcs8', getRawKey('PRIVATE', privKey),
      {
        name: 'RSA-OAEP',
        modulusLength: 2048,
        publicExponent: new Uint8Array([1, 0, 1]),
        hash: {name: 'SHA-256'}
      }, true, ['decrypt'])
        .then(function(privateKey) {
          return subtlePony('decrypt', { name: 'RSA-OAEP', hash: {name: 'SHA-256'}}, privateKey, encrypted)})})
    .then(function(content) { log((new TextDecoder()).decode(content))})
})