Secure cookies

The client uses cookies to track account logins and active survey sessions. Both uses are security sensitive, which means the cookies should be authenticated before they can be trusted.

To do this we a simple signing system for both cookies. An account gets a new secret property which contains random data. This will be used to create a signature for cookie values. On each login a new secret is generated to prevent replay attacks.

See euphorie.client.cookie for the relevant API methods.