3.3.1. TLS Extension

3.3.1. TLS Extension

The SCT can be sent during the TLS handshake using a TLS extension with type "signed_certificate_timestamp".

Clients that support the extension SHOULD send a ClientHello extension with the appropriate type and empty "extension_data".

Servers MUST only send SCTs to clients who have indicated support for the extension in the ClientHello, in which case the SCTs are sent by setting the "extension_data" to a "SignedCertificateTimestampList".

Session resumption uses the original session information: clients SHOULD include the extension type in the ClientHello, but if the session is resumed, the server is not expected to process it or include the extension in the ServerHello.