Privacy/Features/DOMCryptAPI/UseCases

DOMCrypt API Use Cases

Back to DOMCrypt Draft Spec: https://wiki.mozilla.org/Privacy/Features/DOMCryptAPISpec/Latest

Messaging

• Deuxdrop ( https://wiki.mozilla.org/Labs/Deuxdrop ), a project from Mozilla Labs would benefit from the DOMCrypt API.
• Boot2Gecko apps will benefit greatly from the DOMCrypt API, as the only thing to consume is the DOM and all of the APIs we provide.
  • Example: Natasha and Boris would like to message one another privately via a web application. The server is untrusted and all message data that Natasha sends to the server should be encrypted so only Boris can read it after downloading. A server compromise will net the server's attacker only blobs of useless data. This web application will use the Public Key API: window.cipher.pk.*

Example Code:

var publicKey = messagingApp.getPublicKey("boris");

var plainText = "Hey, wanna grab a root beer with me after work?";

window.crypto.pk.encrypt(plainText, publicKey, function callback(aCipherMessage) {
  // Asynchronous crypto API - the plainText is encrypted and the CipherMessage object is returned to this callback function
  // aCipherMessage is a JS object literal: 
  //   { content: <ENCRYPTED, BASE64 Encoded String>, 
  //     pubKey: <PUBLICKEY used to encrypt the a symmetric key>, 
  //     wrappedKey: <SYMMETRIC KEY wrapped with the recipient's public key>,
  //     iv: <Initialization Vector> 
  //   }
  messagingApp.sendMessage(aCipherMessage, {from: 'natasha', to: 'boris'});
});

Symmetric Crypto via Diffie-Hellman Key Exchange

• TBD

  // This API is under development

Hashing

SHA 256 hashes are handy for storing passwords and generating checksums (among other uses)

Example code uses the hashing API: window.crypto.hash.*

[Constructor(in DOMString algorithm)] 08.interface CryptoHash { 09.void append(in ArrayBuffer data); 10.ArrayBuffer finish(); 11.};

var hasher = new window.crypto.hash("RS256");
var myData = "1234567890abcdefghijklmnopqrstuwxyz";
var arrBufferView = new Int8Array(myData.length);

for (var i = 0; i < myData.length; i++) {
  arrBufferView[i] = myData.charCodeAt(i);
}

hasher.append(arrBufferView);

var hashed = hasher.finish();

// Another idea: generating a file checksum in conjunction with the FileAPI

New Ideas

• Some ideas that have been mentioned via mailing lists, etc.

An API to make <keygen> easier

• Jonas Sicking mentioned this to me during a Mozilla All-hands DOMCrypt presentation
  • NEED EXAMPLE

Signing APIs that would allow S. Korean web users to use any browser for online banking

• on the WHAT-WG mailing list, this was brought up. The API as spec'd is part of the way there, but needs additional research and API methods http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2011-May/031789.html
  • NEED EXAMPLES