List and briefly defined categories of security services.

There are six categories of security services: authenticiation, access control, data confidentiality, data integrity, nonrepudiation, and availability service. First, is authentication service, which defines as the assurance that the communicator is legitimate and is the one that it claims to be. It can either be peer entity or data origin authentication. Second, access control which is to prevent any unauthorized uses of resources. After one is being authenticiated, then this service limit/controls who access? what accessing rights to the resources are allowed depending on the identified individuals. Data confifentiality: the protection of data from unauthorized disclosure. Data integrity: the assurance that data received are exactly as sent by an authorized entity (e.t.c, contain no modificafion, insertion, deletion, or replay).

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