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[imagemagick] / www / cipher.html

diff --git a/www/cipher.html b/www/cipher.html
index 86015a4d9eeebb795c8a42dc8b8f266356215df1..c4e88a8dee2e8d9a4122f3106ac20e37c86122f3 100644 (file)
--- a/www/cipher.html
+++ b/www/cipher.html
@@ -130,6 +130,9 @@
 <div  class="sponsor">
    <a title="Sponsor: Webdesign" href="http://www.renehornig.com/">Webdesign</a><!-- 20111001000240 -->
 </div>
+<div  class="sponsor">
+  <a title="Sponsor: Druckerei" href="http://print24.com/de/">Druckerei</a><!-- 201110010720 -->
+</div>
 <div  class="sponsor">
   <a title="Sponsor: Image Converter" href="http://www.batchphoto.com">Image Converter</a><!-- 201103010900 Bits Coffee-->
 </div>
@@ -201,17 +204,40 @@
 <h2><a name="caveats"></a>Encipher and Decipher Caveats</h2>
 <div class="doc-section">
 
-<p>Some formats do not support enciphered pixels-- the JPEG or GIF format, for example.  To ensure your image format is supported, encipher a test image and verify you can restore its original content <em>before</em> you encipher any additional images in that format.</p>
+<p>Some formats do not support enciphered pixels-- the JPEG or GIF format, for
+example.  To ensure your image format is supported, encipher a test image and
+verify you can restore its original content <em>before</em> you encipher any
+additional images in that format.</p>
+
+<p>The image format also should be 8-bit and RGB (TrueColor). As such you may
+like to include the options "-depth 8 -type TrueColor" before the output
+filename. </p>
+
+<p>The passphrase can be any combinations of letters and symbols.  It should
+be a minimum of 12 character combinations to help ensure your image remains
+private.  Also make sure your passphrase file permissions prevent others from
+reading it otherwise unintended users may be able to view the original image
+content.</p>
 
-<p>The passphrase can be any combinations of letters and symbols.  It should be a minimum of 12 character combinations to help ensure your image remains private.  Also make sure your passphrase file permissions prevent others from reading it otherwise unintended users may be able to view the original image content.</p>
+<p>You can only restore the original image content if you know your
+passphrase.  If you lose or forget it, your original image content is lost
+forever.</p>
 
-<p>You can only restore the original image content if you know your passphrase.  If you lose or forget it, your original image content is lost forever.</p>
+<p>ImageMagick only scrambles the image pixels.  The image metadata remains
+untouched and readable by anyone with access to the image file.</p>
 
-<p>ImageMagick only scrambles the image pixels.  The image metadata remains untouched and readable by anyone with access to the image file.</p>
+<p>ImageMagick uses the <a
+href="http://en.wikipedia.org/wiki/Advanced_Encryption_Standard">AES</a>
+cipher in cipher feedback mode.  We use the passphrase to derive the cipher
+key and the required nonce.</p>
 
-<p>ImageMagick uses the <a href="http://en.wikipedia.org/wiki/Advanced_Encryption_Standard">AES</a> cipher in cipher feedback mode.  We use the passphrase to derive the cipher key and the required nonce.</p>
+<p>Currently only ImageMagick can restore your enciphered image content.  We
+use a standard cipher and mode so other vendors are encouraged to support
+enciphered image content.</p>
 
-<p>Currently only ImageMagick can restore your enciphered image content.  We use a standard cipher and mode so other vendors are encouraged to support enciphered image content.</p>
+<p>Some small practical examples of image enciphering can be found in IM
+Examples <A HREF="http://www.imagemagick.org/Usage/transform/#encipher"
+>Encrypting Image Data</A>. </p>
 
 </div>
 \r