I have a record in a Configuration table to hold an ActivationCode. This ActivationCode will determine how many instructors the end user is allowed to key in(ie 1,2,10,100 etc).

My question is if anyone knows of an algorithm that can both create and decipher this activation code. I am thinking of an alogorithm that I could, for example, key in 3 and it would output like a 10 character string. Then the form that the enduser uses to add instructors would decipher this ActivationCode and then determine whether or not to allow the Add.

Thanks,
Paul