No, don't do this. People who use the GPG system can handle the decryption of themselves offline.
Simply encrypting the message via JS is just ~3 lines of calling a premade library on the JS side, and a new DB column like the added Bitcoin addresses.
Then they can encrypt it themselves offline too, It takes less than 2 seconds to encrypt it using that site. what's the point of semi automatic pgp system. lazyness?
