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<?xml version="1.0" standalone="no"?>
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<!-- $Id$ -->
<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V2.0//EN" "http://forrest.apache.org/dtd/document-v20.dtd">
<document>
<header>
<title>PDF encryption.</title>
<version>$Revision$</version>
<authors>
<person name="J.Pietschmann" email="pietsch@apache.org"/>
<person name="Jeremias Märki" email="jeremias@apache.org"/>
</authors>
</header>
<body>
<section>
<title>Overview</title>
<warning>
PDF Encryption is available in Release 0.20.5 and later. The comments on this page do
not apply to releases earlier than 0.20.5.
</warning>
<p>
FOP supports encryption of PDF output, thanks to Patrick
C. Lankswert. This feature is commonly used to prevent
unauthorized viewing, printing, editing, copying text from the
document and doing annotations. It is also possible to ask the
user for a password in order to view the contents. Note that
there already exist third party applications which can decrypt
an encrypted PDF without effort and allow the aforementioned
operations, therefore the degree of protection is limited.
</p>
<p>
For further information about features and restrictions regarding PDF
encryption, look at the documentation coming with Adobe Acrobat or the
technical documentation on the Adobe web site.
</p>
</section>
<section>
<title>Usage (command line)</title>
<p>
Encryption is enabled by supplying any of the encryption related
options.
</p>
<p>
An owner password is set with the <code>-o</code> option. This
password is actually used as encryption key. Many tools for
PDF processing ask for this password to disregard any
restriction imposed on the PDF document.
</p>
<p>
If no owner password has been supplied but FOP was asked to apply some
restrictions, a random password is used. In this case it is obviously
impossiible to disregard restrictions in PDF processing tools.
</p>
<p>
A user password, supplied with the <code>-u</code> option, will
cause the PDF display software to ask the reader for this password in
order to view the contents of the document. If no user password was
supplied, viewing the content is not restricted.
</p>
<p>
Further restrictions can be imposed by using the <code>-noprint</code>,
<code>-nocopy</code>, <code>-noedit</code> and
<code>-noannotations</code> options, which disable printing, copying
text, editing in Adobe Acrobat and making annotations, respectively.
</p>
</section>
<section>
<title>Usage (embedded)</title>
<p>
When FOP is embedded in another Java application you need to set an
options map on the renderer. These are the supported options:
</p>
<table>
<tr>
<th>Option</th>
<th>Description</th>
<th>Values</th>
<th>Default</th>
</tr>
<tr>
<td>ownerPassword</td>
<td>The owner password</td>
<td>String</td>
<td/>
</tr>
<tr>
<td>userPassword</td>
<td>The user password</td>
<td>String</td>
<td/>
</tr>
<tr>
<td>allowPrint</td>
<td>Allows/disallows printing of the PDF</td>
<td>"TRUE" or "FALSE"</td>
<td>"TRUE"</td>
</tr>
<tr>
<td>allowCopyContent</td>
<td>Allows/disallows copy/paste of content</td>
<td>"TRUE" or "FALSE"</td>
<td>"TRUE"</td>
</tr>
<tr>
<td>allowEditContent</td>
<td>Allows/disallows editing of content</td>
<td>"TRUE" or "FALSE"</td>
<td>"TRUE"</td>
</tr>
<tr>
<td>allowEditAnnotations</td>
<td>Allows/disallows editing of annotations</td>
<td>"TRUE" or "FALSE"</td>
<td>"TRUE"</td>
</tr>
</table>
<note>
Encryption is enabled as soon as one of these options is set.
</note>
<p>
An example to enable PDF encryption in Java code:
</p>
<source><![CDATA[
import org.apache.fop.pdf.PDFEncryptionParams;
[..]
FOUserAgent userAgent = fopFactory.newFOUserAgent();
useragent.getRendererOptions().put("encryption-params", new PDFEncryptionParams(
null, "password", false, false, true, true));
Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, userAgent);
[..]]]></source>
<p>
The parameters for the constructor of PDFEncryptionParams are:
</p>
<ol>
<li>userPassword: String, may be null</li>
<li>ownerPassword: String, may be null</li>
<li>allowPrint: true if printing is allowed</li>
<li>allowCopyContent: true if copying content is allowed</li>
<li>allowEditContent: true if editing content is allowed</li>
<li>allowEditAnnotations: true if editing annotations is allowed</li>
</ol>
<p>
Alternatively, you can set each value separately in the Map provided by
FOUserAgent.getRendererOptions() by using the following keys:
</p>
<ol>
<li>user-password: String</li>
<li>owner-password: String</li>
<li>noprint: Boolean or "true"/"false"</li>
<li>nocopy: Boolean or "true"/"false"</li>
<li>noedit: Boolean or "true"/"false"</li>
<li>noannotations: Boolean or "true"/"false"</li>
</ol>
</section>
<section>
<title>Environment</title>
<p>
In order to use PDF encryption, FOP has to be compiled with
cryptography support. Currently, only <a
href="http://java.sun.com/j2se/1.4/docs/guide/security/jce/JCERefGuide.html">JCE</a>
is supported. JCE is part of JDK 1.4. For earlier JDKs, it can
be installed separately. The build process automatically
detects JCE presence and installs PDF encryption support if
possible, otherwise a stub is compiled in.
</p>
<p>
Cryptography support must also be present at run time. In particular, a
provider for the RC4 cipher is needed. Unfortunately, the sample JCE
provider in Sun's JDK 1.4 does <strong>not</strong> provide RC4. If you
get a message saying
</p>
<source>"Cannot find any provider supporting RC4"</source>
<p>
then you don't have the needed infrastructure.
</p>
<p>
There are several commercial and a few Open Source packages which
provide RC4. A pure Java implementation is produced by <a
href="http://www.bouncycastle.org/">The Legion of the Bouncy
Castle</a>. <a
href="http://www.mozilla.org/projects/security/pki/jss/">Mozilla
JSS</a> is an interface to a native implementation.
</p>
</section>
<section id="install_crypto">
<title>Installing a crypto provider</title>
<p>
The pure Java implementation from <a
href="http://www.bouncycastle.org/">Bouncy Castle</a> is easy to
install.
</p>
<ol>
<li>
Download the binary distribution for your JDK version. If you have JDK
1.3 or earlier you must also download a JCE from the same page.
</li>
<li>
Unpack the distribution. Add the jar file to your classpath. A
convenient way to use the jar on Linux is to simply drop it into the
FOP lib directory, it will be automatically picked up by
<code>fop.sh</code>. If you have JDK 1.3 or earlier don't forget to
install the JCE as well.
</li>
<li>
Open the <code>java.security</code> file and add<br/>
<code>security.provider.6=org.bouncycastle.jce.provider.BouncyCastleProvider</code>,<br/>
preferably at the end of the block defining the other crypto
providers. For JDK 1.4 this is detailed on <a href="http://java.sun.com/j2se/1.4/docs/guide/security/jce/JCERefGuide.html#InstallProvider">Sun's web site</a>.
</li>
</ol>
<p>
If you have any experience with Mozilla JSS or any other
cryptography provider, please post it to the fop-user list.
</p>
</section>
</body>
</document>
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