181 lines
11 KiB
HTML
181 lines
11 KiB
HTML
|
|
|
|
|
|
|
|
<!DOCTYPE html>
|
|
<html lang="en">
|
|
<head>
|
|
<meta charset="utf-8" />
|
|
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
|
|
<title>ImageMagick - Encipher or Decipher an Image</title>
|
|
<meta name="application-name" content="ImageMagick" />
|
|
<meta name="description" content="Use ImageMagick® to create, edit, compose, and convert bitmap images. Resize an image, crop it, change its shades and colors, add captions, and more." />
|
|
<meta name="application-url" content="https://legacy.imagemagick.org" />
|
|
<meta name="generator" content="PHP" />
|
|
<meta name="keywords" content="encipher, or, decipher, an, image, image converter, image resizer, image editor, photo editor, jpg converter, png converter, tiff converter, vector images, online, free, swiss army" />
|
|
<meta name="rating" content="GENERAL" />
|
|
<meta name="robots" content="INDEX, FOLLOW" />
|
|
<meta name="generator" content="ImageMagick Studio LLC" />
|
|
<meta name="author" content="ImageMagick Studio LLC" />
|
|
<meta name="revisit-after" content="2 DAYS" />
|
|
<meta name="resource-type" content="document" />
|
|
<meta name="copyright" content="Copyright (c) 1999-2020 ImageMagick Studio LLC" />
|
|
<meta name="distribution" content="Global" />
|
|
<meta name="magick-serial" content="P131-S030410-R485315270133-P82224-A6668-G1245-1" />
|
|
<meta property='og:url' content='https://legacy.imagemagick.org/' />
|
|
<meta property='og:title' content='ImageMagick Legacy' />
|
|
<meta property='og:image' content='https://legacy.imagemagick.org/images/logo.png' />
|
|
<meta property='og:type' content='website' />
|
|
<meta property='og:site_name' content='ImageMagick Legacy' />
|
|
<meta property='og:description' content="Create, Edit, Compose, or Convert Bitmap Images" />
|
|
<meta name="google-site-verification" content="_bMOCDpkx9ZAzBwb2kF3PRHbfUUdFj2uO8Jd1AXArz4" />
|
|
<meta name="msvalidate.01" content="103012B23499FEB70AEA89C83C274AC7" />
|
|
<link href="cipher.html" rel="canonical" />
|
|
<link href="../images/wand.png" rel="icon" />
|
|
<link href="../images/wand.ico" rel="shortcut icon" />
|
|
<link href="assets/magick.css" rel="stylesheet" />
|
|
</head>
|
|
<body>
|
|
<nav class="navbar navbar-expand-md navbar-dark fixed-top bg-dark">
|
|
<a class="navbar-brand" href="../index.html"><img class="d-block" id="wand" alt="ImageMagick" width="32" height="32" src="../images/wand.ico"/></a>
|
|
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarsMagick" aria-controls="navbarsMagick" aria-expanded="false" aria-label="Toggle navigation">
|
|
<span class="navbar-toggler-icon"></span>
|
|
</button>
|
|
|
|
<div class="navbar-collapse collapse" id="navbarsMagick" style="">
|
|
<ul class="navbar-nav mr-auto">
|
|
<li class="nav-item ">
|
|
<a class="nav-link" href="../index.html">Home <span class="sr-only">(current)</span></a>
|
|
</li>
|
|
<li class="nav-item ">
|
|
<a class="nav-link" href="download.html">Download</a>
|
|
</li>
|
|
<li class="nav-item ">
|
|
<a class="nav-link" href="command-line-tools.html">Tools</a>
|
|
</li>
|
|
<li class="nav-item ">
|
|
<a class="nav-link" href="command-line-processing.html">Command-line</a>
|
|
</li>
|
|
<li class="nav-item ">
|
|
<a class="nav-link" href="develop.html">Develop</a>
|
|
</li>
|
|
<li class="nav-item">
|
|
<a class="nav-link" target="_blank" href="https://github.com/ImageMagick/ImageMagick6/discussions">Community</a>
|
|
</li>
|
|
<li class="nav-item">
|
|
<iframe src="https://github.com/sponsors/ImageMagick/button" title="Sponsor ImageMagick" height="35" width="107" style="border: 0;"></iframe>
|
|
</li>
|
|
</ul>
|
|
</div>
|
|
<form class="form-inline my-2 my-lg-0" action="https://legacy.imagemagick.org/script/search.php">
|
|
<input class="form-control mr-sm-2" type="text" name="q" placeholder="Search" aria-label="Search" />
|
|
<button class="btn btn-outline-success my-2 my-sm-0" type="submit" name="sa">Search</button>
|
|
</form>
|
|
</nav>
|
|
<div role="main" class="container">
|
|
<script async="async" src="https://localhost/pagead/js/adsbygoogle.js"></script> <ins class="adsbygoogle"
|
|
style="display:block"
|
|
data-ad-client="ca-pub-3129977114552745"
|
|
data-ad-slot="6345125851"
|
|
data-full-width-responsive="true"
|
|
data-ad-format="horizontal"></ins>
|
|
<script>
|
|
(adsbygoogle = window.adsbygoogle || []).push({});
|
|
</script>
|
|
</div>
|
|
|
|
<main class="container">
|
|
<div class="magick-template">
|
|
<div class="magick-header">
|
|
<h1 class="text-center">Encipher or Decipher an Image</h1>
|
|
<p class="text-center"><a href="cipher.html#encipher">Encipher an Image</a> • <a href="cipher.html#decipher">Decipher an Image</a> • <a href="cipher.html#caveats">Encipher and Decipher Caveats</a></p>
|
|
|
|
<p class="lead magick-description">Most images, by design, are made to be viewed often and by many people. Web images, for example, may be viewed hundreds of times a day by a multitude of vistors. However, in some cases, you may want to keep a particular image private so that only you or perhaps a select group of your friends or web visitors can view it. ImageMagick permits you to scramble your images such that unless someone knows your passphrase, they will be unable to view the original content.</p>
|
|
|
|
<p>You could use an <a href="https://github.com/ImageMagick/WizardsToolkit">enciphering</a> utility to scramble your image but they typically scramble the entire file making it unrecognizable as an image format. With ImageMagick, only the pixels are scrambled. The scrambled image continues to be recognized as an image and will even display in your web page. However, the content appears as gibberish, nothing like the original content.</p>
|
|
|
|
<h2><a class="anchor" id="encipher"></a>Encipher an Image</h2>
|
|
|
|
<p>Use the <a href="command-line-options.html#encipher">-encipher</a> option to scramble your image so that it is unrecognizable. The option requires a filename that contains your passphrase. In this example we scramble an image and save it in the PNG format:</p>
|
|
|
|
<pre class="highlight"><code>convert rose.jpg -encipher passphrase.txt rose.png
|
|
</code></pre>
|
|
|
|
<p>Here we encipher an image using another image as the passphrase:</p>
|
|
|
|
<pre class="highlight"><code>convert rose.jpg -encipher smiley.gif rose.png
|
|
</code></pre>
|
|
|
|
<h2><a class="anchor" id="decipher"></a>Decipher an Image</h2>
|
|
|
|
<p>Use the <a href="command-line-options.html#decipher">-decipher</a> option to unscramble your image so that it is recognizable once again. The option requires a filename that contains your passphrase. In this example we unscramble an image and save it in the JPEG format:</p>
|
|
|
|
<pre class="highlight"><code>convert rose.png -decipher passphrase.txt rose.jpg
|
|
</code></pre>
|
|
|
|
<h2><a class="anchor" id="caveats"></a>Encipher and Decipher Caveats</h2>
|
|
|
|
<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 <var>before</var> you encipher any
|
|
additional images in that format.</p>
|
|
|
|
<p>The image format may only support 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>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 uses the <a
|
|
href="http://en.wikipedia.org/wiki/Advanced_Encryption_Standard">AES</a>
|
|
cipher in Counter mode. We use the first half of your passphrase to derive the nonce. The second half is the cipher key. When used correctly, AES-CTR provides a high level of confidentiality. To avoid information leaks, you must use a fresh passphrase for each image your encrypt.</p>
|
|
|
|
<p>Currently only ImageMagick can restore your enciphered image content. We
|
|
use a standard cipher and mode so other vendors could support enciphered image content.</p>
|
|
|
|
<p>Some small practical examples of image enciphering can be found in IM
|
|
Examples <a href="https://legacy.imagemagick.org/Usage/transform/#encipher"
|
|
>Encrypting Image Data</a>. </p>
|
|
|
|
</div>
|
|
</div>
|
|
</main><!-- /.container -->
|
|
<footer class="magick-footer">
|
|
<div class="container">
|
|
<p><a href="security-policy.html">Security</a> •
|
|
<a href="news.html">News</a>
|
|
|
|
<a href="cipher.html#"><img class="d-inline" id="wand" alt="And Now a Touch of Magick" width="16" height="16" src="../images/wand.ico"/></a>
|
|
|
|
<a href="links.html">Related</a> •
|
|
<a href="sitemap.html">Sitemap</a>
|
|
<br/>
|
|
|
|
<a href="support.html">Sponsor</a> •
|
|
<a href="http://pgp.mit.edu/pks/lookup?op=get&search=0x89AB63D48277377A">Public Key</a> •
|
|
<a href="https://imagemagick.org/script/contact.php">Contact Us</a>
|
|
<br/>
|
|
<a href="https://github.com/imagemagick/imagemagick6" target="_blank" rel="noopener" aria-label="GitHub"><svg xmlns="http://www.w3.org/2000/svg" class="navbar-nav-svg" viewBox="0 0 512 499.36" width="2%" height="2%" role="img" focusable="false"><title>GitHub</title><path fill="currentColor" fill-rule="evenodd" d="M256 0C114.64 0 0 114.61 0 256c0 113.09 73.34 209 175.08 242.9 12.8 2.35 17.47-5.56 17.47-12.34 0-6.08-.22-22.18-.35-43.54-71.2 15.49-86.2-34.34-86.2-34.34-11.64-29.57-28.42-37.45-28.42-37.45-23.27-15.84 1.73-15.55 1.73-15.55 25.69 1.81 39.21 26.38 39.21 26.38 22.84 39.12 59.92 27.82 74.5 21.27 2.33-16.54 8.94-27.82 16.25-34.22-56.84-6.43-116.6-28.43-116.6-126.49 0-27.95 10-50.8 26.35-68.69-2.63-6.48-11.42-32.5 2.51-67.75 0 0 21.49-6.88 70.4 26.24a242.65 242.65 0 0 1 128.18 0c48.87-33.13 70.33-26.24 70.33-26.24 14 35.25 5.18 61.27 2.55 67.75 16.41 17.9 26.31 40.75 26.31 68.69 0 98.35-59.85 120-116.88 126.32 9.19 7.9 17.38 23.53 17.38 47.41 0 34.22-.31 61.83-.31 70.23 0 6.85 4.61 14.81 17.6 12.31C438.72 464.97 512 369.08 512 256.02 512 114.62 397.37 0 256 0z"/></svg></a> •
|
|
<a href="https://twitter.com/imagemagick" target="_blank" rel="noopener" aria-label="Twitter"><svg xmlns="http://www.w3.org/2000/svg" class="navbar-nav-svg" viewBox="0 0 512 416.32" width="2%" height="2%" role="img" focusable="false"><title>Twitter</title><path fill="currentColor" d="M160.83 416.32c193.2 0 298.92-160.22 298.92-298.92 0-4.51 0-9-.2-13.52A214 214 0 0 0 512 49.38a212.93 212.93 0 0 1-60.44 16.6 105.7 105.7 0 0 0 46.3-58.19 209 209 0 0 1-66.79 25.37 105.09 105.09 0 0 0-181.73 71.91 116.12 116.12 0 0 0 2.66 24c-87.28-4.3-164.73-46.3-216.56-109.82A105.48 105.48 0 0 0 68 159.6a106.27 106.27 0 0 1-47.53-13.11v1.43a105.28 105.28 0 0 0 84.21 103.06 105.67 105.67 0 0 1-47.33 1.84 105.06 105.06 0 0 0 98.14 72.94A210.72 210.72 0 0 1 25 370.84a202.17 202.17 0 0 1-25-1.43 298.85 298.85 0 0 0 160.83 46.92"/></svg></a>
|
|
<br/>
|
|
<small>© 1999-2021 ImageMagick Studio LLC</small></p>
|
|
</div>
|
|
</footer>
|
|
|
|
<!-- Javascript assets -->
|
|
<script>window.jQuery || document.write('<script src="assets/jquery.slim.min.js"><\/script>')</script><script src="assets/bootstrap.bundle.min.js" crossorigin="anonymous" />
|
|
</body>
|
|
</html>
|
|
<!-- Magick Cache 1st January 2021 18:34 -->
|