CHAP
Challenge Handshake Authentication Protocol
An authentication protocol that verifies identity using a periodic challenge and response.
CHAP authenticates a peer using a three way handshake in which the server sends a challenge, the client returns a hash of the challenge combined with a shared secret, and the server compares it against its own computation. The secret itself never crosses the link, and periodic rechallenges protect against replay during a session. This is a clear improvement over PAP, which transmits credentials in cleartext. CHAP still requires both sides to store the shared secret to verify responses.
Challenge-Handshake: challenges with a hash and never sends the password itself.
Looking CHAP up is step one. Getting tested on it is step two.
A free account opens all 4 Domain 1 objectives, 271 exam-style questions with a lesson and a lab on each, a placement check that skips what you already know, and a dated plan. No card.
Not affiliated with or endorsed by CompTIA.