title: What size of initialization vector needed for AES-256 encryption in java?
body: <p>I am using AES-256 encryption with CFB mode. I have to use 32 byte key.
  But I am little bit confused about the initialization vector. 
  How many bytes of initialization vector should be used with AES-256 ?
  Is it 16 bytes or 32 bytes  ?</p>
  
  <p>Any code example will be appreciated.</p>