Document Name: RFC 9163
Document URI: urn:ietf:rfc:9163
Online Version:
Organization: Internet Engineering Task Force (IETF)
Series: Request for Comments (RFC)
Abstract: This document defines a new HTTP header field named "Expect-CT", which allows web host operators to instruct user agents (UAs) to expect valid Signed Certificate Timestamps (SCTs) to be served on connections to these hosts. Expect-CT allows web host operators to discover misconfigurations in their Certificate Transparency (CT) deployments. Further, web host operators can use Expect-CT to ensure that if a UA that supports Expect-CT accepts a misissued certificate, that certificate will be discoverable in Certificate Transparency logs.

Specified Web Concepts:

HTTP Header Fields


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