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Glossary

CHAP (Challenge Handshake Authentication Protocol) in 3GPP: meaning and where it is specified

Published 2026-10-16Updated 2026-10-16

At a glance

Term
CHAP
Stands for
Challenge Handshake Authentication Protocol
Defined in
3GPP TR 21.905 V19.2.0, clause 4
Used in
TS 24.008, TS 24.302, TS 33.402

In plain words

CHAP means Challenge Handshake Authentication Protocol, as listed in 3GPP TR 21.905. In TS 33.402, if the external AAA server "supports the CHAP procedure", the ePDG sends the UE an EAP MD5-challenge request. TS 24.008 cites the IETF RFC titled PPP Challenge Handshake Authentication Protocol (CHAP). TS 24.302 says to send an EAP MD5-Challenge request to the UE if CHAP authentication is required.

Source: 3GPP TS 33.402 V18.1.0, clause 6.5.3. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/33_series/33.402/33402-i10.zip

Sources

  1. 3GPP TR 21.905 V19.2.0, clause 4. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/21_series/21.905/21905-j20.zip
  2. 3GPP TS 33.402 V18.1.0, clause 6.5.3. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/33_series/33.402/33402-i10.zip
  3. 3GPP TS 24.008 V18.8.0, clause 2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/24_series/24.008/24008-i80.zip
  4. 3GPP TS 24.302 V16.4.0, clause 7.4.1.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/24_series/24.302/24302-g40.zip

How this page was made

The facts box comes straight from the 3GPP TDoc list and specification archive as indexed by 3GPP Scout. An AI model (GPT-6 Luna) wrote the paragraph and named the source of each sentence. Code checked every quote word for word against the stored source text and every number against the cited source. A second AI model from another company (Claude Opus 5.5) reviewed the paragraph against the same sources. The 3GPP documents themselves govern.