On a permission-based list, the URLs have tracking numbers. The question is, what to use?
Generating a random number for each email is quick and easy, but guaranteeing uniqueness is not as quick. It gets increasingly longer as the space is used, and adding more digits can hurt URL length.
Since every email sent is recorded, each already has a unique number. The problem is predictability.
Two solutions were provided. One, encrypting of the unique number. Second, using the unique number and a non-verified random number.
Encryption is kind of kewl. But decryption takes time (especially when many links are hit at the same time) and hard as it is, there is a single point of failure, for any links that use the same encryption key. The neat upside is, length is lower, and nothing more needs to be stored.
The unique number seems odd. It gives a counter in the table, it adds what needs to be stored, and takes time generating the number.
What do you think?