title: How to pick an appropriate IV (Initialization Vector) for AES/CTR/NoPadding?
body: <p>I would like to encrypt the cookies that are written by a webapp and I would like to keep the size of the cookies to minimum, hence the reason I picked AES/CTR/NoPadding.</p>
  
  <p>What would you recommend to use as IV that's random enough and still keep the app stateless. I know that I can just generate a random IV and append it to the message, but that will increase the size of the cookie.</p>
  
  <p>In addition, what's the recommended size of IV for 128-bit AES?</p>
  
  <p>How else is everyone doing this? Do any "tried and true" ways exist? I don't want to reinvent the wheel.</p>