2013/11/13

Devoxx 2013 - Cryptographic operations in the browser

Nick Van den Bleeken
why
  • easy and secure authentication
  • sign/verify messages & docs
  • encrypt docs
existing crypto frameworks (Dojo, CryptoJS, etc.)
  • completely implemented in JavaScript
  • hard to protect against timing attacks (optimizations in JS engine change)
  • Math.random() is not secure
  • hard to get correct
  • performance issues (e.g. number is 64bit float)
alternatives:
  • java plugins
    • disabled in many browsers (recommendation US DHS)
    • not on mobile
  • native extensions
    • separate install
    • browser specific (some browsers drop support for extension!)
    • not on mobile
solution: Web Cryptography API
  • W3C standard: http://www.w3.org/TR/WebCryptoAPI/ (under construction...)
  • JS API for web developers
  • still requires TLS to prevent sniffing communication
  • still relatively complex (requires correct usage of encryption algorithms)
low level API
  • Basic building block: window.crypto.subtle
    • .generateKey(algorithmKeyGen ...)
      • callback when key is generated
    • importKey: add existing keys (e.g. public key of bank)
    • verify() signature
    • decrypt() message
    • sign() message
    • ...
  • use and combine it for more complex operation
high level API:
  • what framework to choose NaCl, KeyCzar, SJCL or ...
  • hard to define
  • existing APIs should address this: JQuery, Dojo, Prototype etc.
  • -> Not for now...
implemented by
  • MS IE11 (old version of spec)
  • chromium (flags)
  • mozilla (under development)
  • missing: Safari...
  • polycrypt (old version of spec)
  • Netflix: webcrypto key discovery
 future need: smartcard support (but: not a focus for US-based companies...)
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