title: AES encryption of 16 bytes without padding
body: <p>This should be a simple question, but I can't find any examples or figure out the answer from the openssl docs.</p>
  
  <p>I want to encrypt <strong>exactly</strong> 128 bits, which should fit in one encryption block.</p>
  
  <p>So I call <code>EVP_EncyptInit_ex</code>, and then what?</p>
  
  <p>Do I call <code>EVP_EncryptUpdate_ex</code> (to encrypt the 128 bit block) and <code>EVP_EncryptFinal_ex</code> (even though there is nothing more left to encrypt)?</p>
  
  <p>Or only <code>EVP_EncryptUpdate_ex</code>?
  Or only <code>EVP_EncryptFinal_ex</code>?</p>