title: OpenSSL using EVP vs. algorithm API for symmetric crypto
body: <p>Hi i have installed openssl on my linux machine and going through the header files and documentation (which is highly insufficint :( ).</p>
  
  <p>i am trying to build a project(in 'c') which uses symmetric crypto algos (i am focusing on aes256cbc).
  The problem is i am confused as in how to use the library functions in my code.</p>
  
  <p>For my implementation of aes256cbc i can directly use the functions defined in the 'aes.h' header file(which appeared to me at the first place).</p>
  
  <p>But on googling i came accross some tutorial for this which are using 'evp.h' functions to do this <a href="http://saju.net.in/code/misc/openssl_aes.c.txt" rel="noreferrer">http://saju.net.in/code/misc/openssl_aes.c.txt</a></p>
  
  <p>Is there a specific reason for this or directly accessing the aes.h functions is better.</p>
  
  <p><strong>And also if someone can point me to a good documentation/tutorial of any kind on using the crypto library of openssl will be much appreciated.</strong></p>
  
  <p>many thanks</p>
  
  <p>P.S forgive me if i am being naive </p>