Required security level for incoming messages.
Possible ValuesNone (0)
Signed And Encrypted (3)
The default value is "Signed And Encrypted", in which case both a valid signature and encryption are required for incoming messages.
Other values include "Signed" and "Encrypted", in which case only a valid signature and/or encryption is required.
Finally, there is a fourth level, "None", which allows all messages. CAUTION: this level is included for debugging purposes only. There is no security with this level.
This property is not available in the Sender.