title: The difference between ECDH-ECDSA-AES128-SHA256 and ECDHE-ECDSA-AES128-SHA256?
body: <p>I am using ECC certificate to observe how TLS works，Can someone helps me the difference between <code>ECDH-ECDSA-AES128-SHA256</code> and <code>ECDHE-ECDSA-AES128-SHA256</code>.</p>
  
  <p>When use <code>ECDHE-ECDSA-AES128-SHA256</code>,client and server works fine.</p>
  
  <pre><code>New, TLSv1/SSLv3, Cipher is ECDHE-ECDSA-AES128-SHA256
  Server public key is 256 bit
  Secure Renegotiation IS supported
  Compression: NONE
  Expansion: NONE
  No ALPN negotiated
  SSL-Session:
      Protocol  : TLSv1.2
      Cipher    : ECDHE-ECDSA-AES128-SHA256
  </code></pre>
  
  <p>When use <code>ECDH-ECDSA-AES128-SHA256</code> ,the <code>SERVER_HELLO</code> fails:</p>
  
  <pre><code>140344027961248:error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure:s23_clnt.c:769:
  </code></pre>