I get the message "Secure Renegotiation IS NOT supported" if a TLS 1.3 cipher will be chosen at a TLS handshake with openssl s_client. Since TLS 1.3 does not support renegotiation at all I assume that this message can be ignored. Is my assumption correct?

  • $\begingroup$ Welcome to crypto.stackexchange - This appears to be a question about programming, rather than about cryptography itself. Is it a programming question? If so, it belongs on stackoverflow, and I can move it there for you. Programming questions are off-topic here, even if they are working with cryptography. If not, you'll want to explain why it is not so that the community does not vote to close it as a programming question. $\endgroup$ – Ella Rose Jan 28 at 20:42
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    $\begingroup$ @EllaRose+ there is no programming here; this is a question about the protocol, which is at least primarily a security-by-crypto protocol (though some features like SNI, NPN/ALPN, and close_notify are arguably noncrypto) and protocols are listed in the help center $\endgroup$ – dave_thompson_085 Jan 29 at 5:22
  • $\begingroup$ @dave_thompson_085 I think we will need OP to state that and modify their question to be more clear about this; There are 3 votes from the community attempting to close it as a programming question, so it's definitely not clear as it is written now. $\endgroup$ – Ella Rose Jan 29 at 14:59

Yes, since TLS1.3 forbids any renegotiation, supporting rfc5746 with it would be meaningless, and rfc8446 doesn't even mention the possibility.

Of course an endpoint that supports both 1.3 and lower versions should (in the 2119-capitalized sense) use 5746 for sessions that negotiate a lower version, and (AFAIK) OpenSSL does.


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