Challenge-Handshake Authentication Protocol: Difference between revisions

Revision as of 15:09, 24 February 2014

Revision as of 09:53, 4 August 2014

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In [[computing]], the '''Challenge-Handshake Authentication Protocol''' ('''CHAP)''') [[authentication|authenticates]] a user or network host to an authenticating entity. That entity may be, for example, an [[Internet service provider]]. CHAP is specified in RFC 1994.

CHAP provides protection against [[replay attack]]s by the peer through the use of an incrementally changing identifier and of a variable challenge-value. CHAP requires that both the client and server know the plaintext of the secret, although it is never sent over the network. The [[MS-CHAP]] variant does not require either peer to know the plaintext, but has been broken.<ref>{{cite web