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Access Tokens

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Cybersecurity 20 Sep 2026 7 min read

DPoP Binds OAuth Access Tokens to a Client Key

DPoP Binds OAuth Access Tokens to a Client Key A bearer access token is usable by any party that obtains the token and can present it to the resource server. TLS protects the token while it crosses a correctly authenticated connection, but it does not change that bearer property after the token reaches an endpoint, log, process, browser context, or other storage location. Demonstrating Proof of Possession (DPoP), specified by RFC 9449, adds a key-bound layer at the application protocol. The client creates an asymmetric key pair and signs a DPoP proof JWT. An authorization server can bind an issued access token to the public key represented by that proof. The resource server then requires both the token and a valid proof created with the corresponding private key.