Apologies, but I am sure I am doing something silly. I can either encrypt a file with another users public key and that works (they can unencrypt it). Or, I can sign a file with my private key and the recipient can verify I signed the file. What is not working for me is to do both e.g. if I merely sign the file it is not protected, but if I sign and encrypt the recipient has trouble verifying I signed the file, but they can un-encrypt. Suggestions please?