Decrypting data with javascript - ASP.NET website

Question

I use a hidden variable (input type=hidden) to store ID information on a page. To prevent attackers, I decided to encrypt the data stored using System.Security.Cryptography.

The hidden variable is accessed in JS and executes validation logic. I will need to decrypt the data before executing the validation logic. Is there a way to decrypt data in JS that was encrypted using System.Security.Cryptography

Answer 1

If you can decrypt it using JavaScript on the client side, so can any attacker. This approach is flawed for that reason. The Validation logic also needs to be done server side. You should never trust client side validation for anything that could potentially hurt your site.