Protected Extensible Authentication Protocol (PEAP)


The Protected Extensible Authentication Protocol, also known as Protected EAP or simply PEAP, is a protocol that encapsulates the Extensible Authentication Protocol (EAP) within an encrypted and authenticated Transport Layer Security (TLS) tunnel. The purpose was to correct deficiencies in EAP; EAP assumed a protected communication channel, such as that provided by physical security, so facilities for protection of the EAP conversation were not provided.

PEAP was jointly developed by Cisco Systems, Microsoft, and RSA Security. PEAPv0 was the version included with Microsoft Windows XP and was nominally defined in draft-kamath-pppext-peapv0-00. PEAPv1 and PEAPv2 were defined in different versions of draft-josefsson-pppext-eap-tls-eap. PEAPv1 was defined in draft-josefsson-pppext-eap-tls-eap-00 through draft-josefsson-pppext-eap-tls-eap-05, and PEAPv2 was defined in versions beginning with draft-josefsson-pppext-eap-tls-eap-06.

The protocol only specifies chaining multiple EAP mechanisms and not any specific method. However, use of the EAP-MSCHAPv2 and EAP-GTC methods are the most commonly supported.


  1. CIT uses PEAP as part of its authentication infrastructure.