Reading out the current illuminance from the Ambient Light Bricklet looks as following:
Authentication can be activated for the Brick Daemon as well as for the Ethernet/WIFI Extension. Additionally we added an authentication tutorial to ease the beginning. To extend an existing program by authentication you usually only have to add one line to your program that sets the authentication secret.
Internally the authentication is done with the HMAC-SHA1 technique. The same technique is for example also used by amazon to authenticate access to Amazon S3.