Agent Engineering
Proof Key for Code Exchange
PKCE binds an OAuth authorization-code flow to a client-generated verifier through an earlier challenge. With the S256 method, the challenge derives from hashing the verifier. A party that intercepts a code without the matching verifier should fail that binding check. This is not a replacement for every other authorization safeguard.
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Sources
Member lesson
The definition and sources are public. The complete practical lesson is for members.