The SignedMessage element represents the secure wrapper used to submit USEF XML messages from the local message queue to the message queue of a remote participant. It contains minimal metadata (which is distinct from the common metadata used for all other messages), allowing the recipient to look up the sender's cryptographic scheme and public keys, and the actual XML message, as transformed (signed/sealed) using that cryptographic scheme. The Internet domain of the USEF participant sending this message. Upon receiving a message, the recipient should validate that its value matches the corresponding attribute value specified in the inner XML message, once un-sealed: if not, the message must be rejected as invalid. The USEF role of the participant sending this message: AGR, BRP, CRO, DSO or MDC. Receive-time validation should take place as described for the SenderDomain attribute above. The Base-64 encoded inner XML message contained in this wrapper, as transformed (signed/sealed) using the sender's cryptographic scheme. The recipient can determine which scheme applies using a DNS or configuration file lookup, based on the combination of SenderDomain and SenderRole. Version of the Shapeshifter specification used by the USEF participant sending this message. The Internet domain of the USEF participant sending this message. When receiving a message, its value should match the value specified in the SignedMessage wrapper: otherwise, the message must be rejected as invalid. When replying to this message, this attribute is used to look up the USEF endpoint the reply message should be delivered to. Internet domain of the participant this message is intended for. When sending a message this attribute is used to look up the Shapeshifter endpoint the message should be delivered to. Date and time this message was created, including the time zone (ISO 8601 formatted as per http://www.w3.org/TR/NOTE-datetime). Unique identifier (UUID/GUID as per IETF RFC 4122) for this message, to be generated when composing each message. Unique identifier (UUID/GUID as per IETF RFC 4122) used to correlate responses with requests, to be generated when composing the first message in a conversation and subsequently copied from the original message to each reply message. MessageID of the message that has just been accepted or rejected. Indication whether the query was executed successfully or failed. In case the query failed, this attribute must contain a human-readable description of the failure reason.