Specifies in which order message must be encrypted and signed.
This property is useful when you need to encrypt and sign message at the same time.
It lets you choose the order of these actions. It can be useful to sign the message after encryption, since such order lets one check the signature without decryption. On the other hand, encryption of signed messages is more secure since it hides the signer's identity from unauthorized view.
Default value is True which means that the message will be signed first.