<p>Am I missing something simple here?  You pad pre-encryption and unless the encryption algorithm is completely flawed then slightly different input files will give completely different output.</p>
<p>In a similar (but entirely unrelated way!) look at the MD5/SHA256/your-fav-hash-function of the numbers 11 & 12. Do you see any similarities in the hash?<br></p>
<p>Olaf</p>
<div class="gmail_quote">On 12/07/2013 5:58 PM, "Iraklis ." <<a href="mailto:leontiad@gmail.com">leontiad@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

  
    
  
  <div text="#000000" bgcolor="#FFFFFF">
    <div>But still someone can identify the
      common pattern at the end of two or more similar files so the pad
      can be detected and deleted, thus length is not hidden.<br>
      On 07/11/2013 09:01 PM, Tony Arcieri wrote:<br>
    </div>
    <blockquote type="cite">
      <div dir="ltr">On Wed, Jul 10, 2013 at 7:31 AM, Ed Kapitein <span dir="ltr"><<a href="mailto:ed@kapitein.org" target="_blank">ed@kapitein.org</a>></span>
        wrote:<br>
        <div class="gmail_extra">
          <div class="gmail_quote">
            <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
              <div><span style="color:rgb(34,34,34)">Hi
                  Zooko,</span><br>
              </div>
              <br>
              Be careful with zero padding, it might leave the data open
              for a<br>
              watermarking attack.<br>
            </blockquote>
            <div><br>
            </div>
            <div>How about padding with the output of a PRNG
              seeded with the content hash? That way it'd still be
              deterministic</div>
          </div>
          <div><br>
          </div>
          -- <br>
          Tony Arcieri<br>
        </div>
      </div>
      <br>
      <fieldset></fieldset>
      <br>
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    </blockquote>
    <br>
  </div>

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