I'll tell you for free that our cookies don't use an auto incrementing id. If you have an asset that is accessed by id, it is beneficial to have a secure, reve

I'll tell you for free that our cookies don't use an auto incrementing id. If you have an asset that is accessed by id, it is beneficial to have a secure, reversable function so that you can prevent trivial crawling while maintaining ease of development. We don't allow chosen plaintexts, so the cryptanalysis here is not relevant. And, even if it did break our use, it would deter most.