title: Set cipher suites used by WinHTTP
body: <p>I would like to use WinHTTP to verify the correctness of some cipher suites which are a modified version of OpenSSL ciphers.</p>
  
  <p>However, I am not able to force WinHTTP to use a specific cipher when contacting a TLS/SSL server. I tried a couple of things, but none worked.</p>
  
  <p>Here is what I tried:</p>
  
  <ol>
  <li>Using the CryptoAPI to remove cipher suites: I basically removed all cipher suites and added the one I wanted to test using the API functions: <code>BCryptAddContextFunction()</code> and <code>BCryptRemoveContextFunction()</code>. Here is a <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/bb870930%28v=vs.85%29.aspx?f=255&amp;MSPPError=-2147217396" rel="nofollow">link</a>.</li>
  <li>Followed instructions <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/bb870930(v=vs.85).aspx" rel="nofollow">here</a> to in the section "To configure the SSL Cipher Suite Order group policy setting".</li>
  </ol>
  
  <p>But none of these worked. Is there any clue how to do this?</p>
  
  <p>btw, I am using Windows 7 Enterprise. And I am verifying what ciphers are being used using Wireshark.</p>
  
  <p>Thank you in advance.</p>