There are five security services. The sub categories are provided by [[X.800]] - [[authenticity]] - peer [[entity authentication]] - [[data origin authentication]] - [[access control]] - [[confidentiality]] - connection confidentiality - connectionless confidentiality - selective-field confidentiality - traffic-flow confidentiality - [[data integrity]] - note links to [[integrity]] - connection integrity with recovery - connection integrity without recovery - selective-field connection integrity - connectionless integrity - selective-field connectionless integrity - [[non-repudiation]] - origin - proof that the message was sent by the specified party - destination - proof that the message was received by the specified party