I need to encrypt a string at client side and send it to the server. Once there I need to decrypt it.
Is the Using Password-Based Encryption the best solution?
I need it because I have a voting mechanism, where I send ajax posts to vote an entry. This mechanism use the Facebook id from the current user. My goal is to encrypt the FB id from client side to avoid that they hack it by sending requests with differents ids. If a second post with the same id is sent I will block the vote.
Once the id is decrypted I will check if it is a real FB user using the graph.