Concurrency issues?

Hello! And THANKS for your work with this. I just implemented this on my server and it works 100% perfect! Thanks!!

I'm just having some doubts now about the two variables "en, de" of type "EVP_CIPHER_CTX".

My server runs a thread connection pool and it has to execute a lot of encryptions and decryptions.
Can I use the same variables "en, de" as global variables in concurrent threads that are constantly encrypting and decrypting?
Or should I create and configure a new "en" and "de" for each operation?

Thankss!