Annex C (normative) UADP Header Layouts ToC

C.2 Message headers for periodic data with fixed layout ToC Previous Next

C.2.6 Header layout for NetworkMessages with integrity and confidentiality (signing and encryption) ToC Previous Next

UADP messages may be signed and encrypted. In this case the SecurityHeader and the Signature have to be added to the message. See clause (UADP Message Security) for a complete description of the security mechanisms.

This header layout is basically the same as the header layout defined in C.2.4 but with additional security level ‘Signing and encryption’.

The NetworkMessage header layout with signing is shown in Figure C.3.

readme_files/image005.png Figure C.3 : UADP NetworkMessage header layout with integrity and confidentiality

Table C.4 shows the configuration for the NetworkMessage header with signing and encryption. The table contains only the added or modified rows from Table C.1.

Table C.4 : UADP NetworkMessage header layout with integrity and confidentiality

Name Type Restrictions
ExtendedFlags1 Byte Bit 4: Security enabled
   SecurityFlags Byte    Bit 0: NetworkMessage Signed enabled   Bit 1: NetworkMessage Encryption enabled   Bit 2: SecurityFooter disabled   Bit 3: Force key reset disabledBit range 4-7: Reserved
   SecurityTokenId IntegerId The ID of the security token that identifies the security key in a SecurityGroup.
   NonceLength Byte 4
   MessageNonce Byte[4] A number used exactly once for a given security key.

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