title: Linux equivalent of WinCrypt API
body: <p>when I need to authenticate client applications against X.509 protected SSL, TLS and SSH based servers in Windows, I use the WinCrypt functions to handle the certificate interfacing functionality.</p>
  
  <p>What is the equivalent of WinCrypt for Linux?, I'm looking for smartcard or secure usb token based APIs where possible.</p>
  
  <p>Thanks.</p>