Annex A (normative) UADP Header Layouts ToC Previous Next

A.3 Message headers for Events and Data with dynamic layout ToC Previous Next

A.3.5 Header layout for NetworkMessages with integrity (signing) ToC Previous Next

UADP messages may be signed to ensure integrity. In this case a security header and a signature have to be added to the message. See clause for a complete description of the signing mechanism.

This header layout is basically the same as the header layout defined in A.3.4 but with additional security level ‘Signing but no encryption’. The NetworkMessage header layout with signing is shown in Figure A.8.

readme_files/image059.png readme_files/image060.png Table A.9 shows the configuration for the NetworkMessage header with signing. The table contains only the added or modified rows from Table A.7.

Table A.9 – UADP NetworkMessage header layout with integrity (signing)

Name Type Restrictions
ExtendedFlags1 Byte Bit 4: Security enabled
   SecurityFlags Byte    Bit 0: NetworkMessage Signed enabled   Bit 1: NetworkMessage Encryption disabled   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 The length of the Nonce used to initialize the encryption algorithm.
   MessageNonce Byte[NonceLength] A number used exactly once for a given security key.

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