Mission Operations Reference Model. Draft ... - CCSDS

DRAFT RECOMMENDED PRACTICE FOR MISSION OPERATIONS REFERENCE MODEL3.6.3 AUTHENTICATION AND AUTHORISATIONAuthentication is a function of the specific protocol in use. For example, digital signaturesare used to ‘sign’ a specific message, and through some feature specific to the authenticationmechanism, the receiver of that message can confirm that the source actually generated themessage. A digital signature is derived from a specific binary representation (or encoding) ofthat message, and because of this the digital signing can be performed only at the encodingstage. Different encodings may support different authentication technologies and alsodifferent ways of representing authentication signatures.a) Authorisation requires authentication; any process that attempts to restrict access tospecific functionality must be able to determine where a specific message originatedbefore it can attempt to perform authorisation. Authorisation is performed bychecking that a specific operation is being performed by an authorised consumer. Thespecific checks are application/deployment specific, but it is expected that it willinvolve a lookup of some configuration based on the information passed as part of themessage.b) Authorisation shall be performed in the MAL. Presented to the MAL by the lowerTransport layer is a generic message with authenticated consumer credentials (whichmay contain time information for ensuring ‘freshness’). It is the responsibility of theMAL to confirm, using an implementation-dependent mechanism through a standardMAL service interface, that the specific consumer is authorised to perform theoperation. If the operation is permitted, then the MAL passes the message to thehigher layer as normal; if not, then a standard error message is returned to theconsumer indicating an authorisation failure.c) The Login service provided by the Common Services (reference [3]) provides themechanisms by which an operator provides his or her security credentials to thesystem; from this point the MAL performs authentication and authorisation usingthese verified credentials.CCSDS 520.1-R-1 Page 3-9 October 2009