What do you think to a solution to something like this;
http://aspalliance.com/1513_Cross_Site_Authentication_and_Data_Transfer.all#Page3
my custom app encrypts a ticket with various parameters userid, expiry date ect... passes it in the querystring thru https to umbraco.
umbraco user control decrypts the querystring (known key) and makes invocation to the database and authenticates the user and gets any data that is required.
the expiry date will be a short time, the encryption key will be private
to gain access to umbraco user details (whatever is retrieved from the usercontrol) - a hacker would need to steal the encrypted querystring within expiry time (this is encrypted over ssl) - or steal our private key, know a users userid and any other information we encrypt in the querystring to gain access to umbraco pages and other user details that are displayed on the umbraco pages - this can also then create its own authentication ticket.
is this an acceptable secure solution?
in what situation would you not use this? and why not? given this information and implementation could you easily steal data?