gistfile1.js

if (!crypto.subtle) {
  crypto.subtle = crypto.webkitSubtle
}

// Encrypt some data using AES-CBC and alert() the result:
// ----------------------------------------
var keyBytes1 = asciiToArrayBufferView("raw key bytes 1.");
crypto.subtle.importKey('raw', keyBytes1, {name: 'aes-cbc'}, false, ['encrypt', 'decrypt']).then(function(key) {
  // Initialization vector of all zeros.
  var iv = asciiToArrayBufferView("16 bytes of iv..");
  var dataToEncrypt = asciiToArrayBufferView("hello world.");
  return crypto.subtle.encrypt({name: 'aes-cbc', iv: iv}, key, dataToEncrypt);
}).then(function(encryptedData) {
  alert('result of encryption: ' + arrayBufferToHexString(encryptedData));
}).then(undefined, function() { alert('failed :(') });

// Sign some data with SHA1 HMAC and alert() the result:
// ----------------------------------------
var keyBytes2 = asciiToArrayBufferView("raw key bytes 2.");
crypto.subtle.importKey('raw', keyBytes2, {name: 'hmac', hash: {name: 'sha-1'}}, false, ['sign']).then(function(key) {
  var dataToSign = asciiToArrayBufferView("it's friday");
  return crypto.subtle.sign({name: 'hmac', hash: {name: 'sha-1'}}, key, dataToSign);
}).then(function(signedData) {
  alert('result of signing: ' + arrayBufferToHexString(signedData));
}).then(undefined, function() { alert('failed :(') });

//---------------------------
// Helper functions to work with arraybuffers
//---------------------------

function asciiToArrayBufferView(str) {
  var chars = [];
  for (var i = 0; i < str.length; ++i)
    chars.push(str.charCodeAt(i));
  return new Uint8Array(chars);
}

function arrayBufferToHexString(arrayBuffer) {
  var bytes = new Uint8Array(arrayBuffer);
  var hexBytes = [];

  for (var i = 0; i < bytes.length; ++i) {
    var byteString = bytes[i].toString(16);
    if (byteString.length < 2)
        byteString = "0" + byteString;
    hexBytes.push(byteString);
  }

  return hexBytes.join("");
}