GSS-API provides per-message security services that can provide confidentiality and/or integrity. Some IETF protocols, such as NFS and SSH, take advantage of these services. As a result, GSS-EAP needs to support these services. As with mutual authentication, per-message security services will limit the set of EAP methods that can be used to those that generate a Master Session Key (MSK). Any EAP method that produces an MSK is able to support per-message security services as described in [RFC2743].