Specifies the order of message signing and encryption.
This property is useful when the message must be signed and encrypted at the same time. It lets you choose the order of these actions. Signing of the message after encryption is useful because such order lets everyone to 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.