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Viktor,</div>
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Thank you for clarifying it.</div>
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<br>
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Yury<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> openssl-users <openssl-users-bounces@openssl.org> on behalf of Viktor Dukhovni <openssl-users@dukhovni.org><br>
<b>Sent:</b> Friday, September 4, 2020 12:10 PM<br>
<b>To:</b> openssl-users@openssl.org <openssl-users@openssl.org><br>
<b>Subject:</b> Re: [EXTERNAL] - Re: Question about TLS 1.3 and openssl -cipher aNULL option</font>
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<div class="PlainText">On Fri, Sep 04, 2020 at 07:00:01PM +0000, Yury Mazin via openssl-users wrote:<br>
<br>
> Thank you Benjamin,<br>
> <br>
> According to OpenSSL , aNULL stands for no-authentication.<br>
<br>
Specifically, SSL 3.0 through TLS 1.2 ciphers in which the server and<br>
client exchange no certificates, and the TLS handshake consists largely<br>
of an unsigned anonymous ephemeral DH or ECDH key exchang.<br>
<br>
TLS 1.3 dropped support for anonymous DH and ECDH. Server certificates<br>
are *required. And the all-in-one ciphersuites of TLS <= 1.2, are<br>
replaced with separately negotiated components. As a result of which,<br>
in OpenSSL 1.1.1 and later, they are controlled via a different set of<br>
APIs and command-line options.<br>
<br>
Specifically, in your case, the "-ciphers aNULL" option only applies<br>
to TLS <= 1.2<br>
<br>
> Does it mean that all 3 default protocols of TLS 1.3 offer no<br>
> authentication<br>
<br>
No. None of them "support no authentication" (which is not even strictly<br>
true, it is the protocol that does not support "no authentication",<br>
the TLS 1.3 ciphers are simply silent re certificate algorithm selection),<br>
but the "-cipher aNULL" is simply not used when TLS 1.3 is negotiated,<br>
so your question is makes incorrect assumptions to reach its tentative<br>
conclusions.<br>
<br>
-- <br>
Viktor.<br>
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