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<a name="TLS-Handshake-Protocol"></a>
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Next: <a href="TLS-Authentication-Methods.html#TLS-Authentication-Methods" accesskey="n" rel="next">TLS Authentication Methods</a>, Previous: <a href="The-TLS-Protocol.html#The-TLS-Protocol" accesskey="p" rel="prev">The TLS Protocol</a>, Up: <a href="Internal-architecture-of-GnuTLS.html#Internal-architecture-of-GnuTLS" accesskey="u" rel="up">Internal architecture of GnuTLS</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Function-and-Data-Index.html#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
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<hr>
<a name="TLS-Handshake-Protocol-1"></a>
<h3 class="section">10.2 TLS Handshake Protocol</h3>
<p>The <acronym>GnuTLS</acronym> handshake protocol is implemented as a state
machine that waits for input or returns immediately when the non-blocking
transport layer functions are used. The main idea is shown in <a href="#fig_002dgnutls_002dhandshake">Figure 10.2</a>.
</p>
<div class="float"><a name="fig_002dgnutls_002dhandshake"></a>
<img src="gnutls-handshake-state.png" alt="gnutls-handshake-state">
<div class="float-caption"><p><strong>Figure 10.2: </strong>GnuTLS handshake state machine.</p></div></div>
<p>Also the way the input is processed varies per ciphersuite. Several
implementations of the internal handlers are available and
<a href="Core-TLS-API.html#gnutls_005fhandshake">gnutls_handshake</a> only multiplexes the input to the appropriate
handler. For example a <acronym>PSK</acronym> ciphersuite has a different
implementation of the <code>process_client_key_exchange</code> than a
certificate ciphersuite. We illustrate the idea in <a href="#fig_002dgnutls_002dhandshake_002dsequence">Figure 10.3</a>.
</p>
<div class="float"><a name="fig_002dgnutls_002dhandshake_002dsequence"></a>
<img src="gnutls-handshake-sequence.png" alt="gnutls-handshake-sequence">
<div class="float-caption"><p><strong>Figure 10.3: </strong>GnuTLS handshake process sequence.</p></div></div>
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