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SynAc
Term

Challenge-Response Authentication Mechanism

A mechanism [R2195], intended for use with IMAP4 AUTHENTICATE, by which an IMAP4 client uses a keyed hash [R2104] to authenticate itself to an IMAP4 server. (See: POP3 APOP.)

Senses

(I) /IMAP4/

A mechanism [R2195], intended for use with IMAP4 AUTHENTICATE, by which an IMAP4 client uses a keyed hash [R2104] to authenticate itself to an IMAP4 server. (See: POP3 APOP.)

Tutorial: The server includes a unique time stamp in its ready response to the client. The client replies with the client's name and the hash result of applying MD5 to a string formed from concatenating the time stamp with a shared secret that is known only to the client and the server.

References
  • IETF RFC 4949 (Internet Security Glossary)Jan 06, 2026
    RFC 4949 — Internet Security Glossary (Version 2)
    https://www.rfc-editor.org/rfc/rfc4949.txt
    RFC 4949 is published by the IETF Trust and marked as "Distribution of this memo is unlimited". Verify IETF Trust copyright/licensing terms for reuse.
    Source: IETF RFC 4949 (rfc-editor.org).