1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta content="Apache Forrest" name="Generator">
<meta name="Forrest-version" content="0.6">
<meta name="Forrest-skin-name" content="pelt">
<title>Frequently Asked Questions - Java</title>
<link type="text/css" href="../skin/basic.css" rel="stylesheet">
<link media="screen" type="text/css" href="../skin/screen.css" rel="stylesheet">
<link media="print" type="text/css" href="../skin/print.css" rel="stylesheet">
<link type="text/css" href="../skin/profile.css" rel="stylesheet">
<script src="../skin/getBlank.js" language="javascript" type="text/javascript"></script><script src="../skin/getMenu.js" language="javascript" type="text/javascript"></script><script src="../skin/fontsize.js" language="javascript" type="text/javascript"></script>
</head>
<body onload="init()">
<script type="text/javascript">ndeSetTextSize();</script>
<div id="top">
<!--+
|breadtrail
+-->
<div class="breadtrail">
<a href="http://www.apache.org/">apache</a> > <a href="http://xml.apache.org/">xml.apache</a><script src="../skin/breadcrumbs.js" language="JavaScript" type="text/javascript"></script>
</div>
<!--+
|header
+-->
<div class="header">
<!--+
|start group logo
+-->
<div class="grouplogo">
<a href="http:///xml.apache.org"><img class="logoImage" alt="Apache XML" src="../images/group-logo.gif"></a>
</div>
<!--+
|end group logo
+-->
<!--+
|start Project Logo
+-->
<div class="projectlogo">
<a href="http://xml.apache.org/security"><img class="logoImage" alt="Apache XML Security" src="../images/project-logo.gif"></a>
</div>
<!--+
|end Project Logo
+-->
<!--+
|start Search
+-->
<div class="searchbox">
<form action="http://www.google.com/search" method="get" class="roundtopsmall">
<input value="xml.apache.org/security" name="sitesearch" type="hidden"><input onFocus="getBlank (this, 'Search the site with google:');" value="Search the site with google:" size="25" name="q" id="query" type="text">
<input name="Search" value="Search" type="submit">
</form>
</div>
<!--+
|end search
+-->
<!--+
|start Tabs
+-->
<ul id="tabs">
<li>
<a class="base-not-selected" href="../index.html">Home</a>
</li>
<li class="current">
<a class="base-selected" href="../Java/index.html">Java</a>
</li>
<li>
<a class="base-not-selected" href="../c/index.html">C++</a>
</li>
</ul>
<!--+
|end Tabs
+-->
</div>
</div>
<div id="main">
<div id="publishedStrip">
<!--+
|start Subtabs
+-->
<div id="level2tabs"></div>
<!--+
|end Endtabs
+-->
<script type="text/javascript" language="JavaScript"><!--
document.write("Published: " + document.lastModified);
// --></script>
</div>
<!--+
|breadtrail
+-->
<div class="breadtrail">
</div>
<!--+
|start Menu, mainarea
+-->
<!--+
|start Menu
+-->
<div id="menu">
<div onclick="SwitchMenu('menu_selected_1.1', '../skin/')" id="menu_selected_1.1Title" class="menutitle" style="background-image: url('../skin/images/chapter_open.gif');">Java</div>
<div id="menu_selected_1.1" class="selectedmenuitemgroup" style="display: block;">
<div class="menuitem">
<a title="" href="../Java/index.html">Index</a>
</div>
<div class="menuitem">
<a title="" href="../Java/installation.html">Installation</a>
</div>
<div class="menuitem">
<a title="" href="../Java/examples.html">Examples</a>
</div>
<div class="menupage">
<div class="menupagetitle">FAQs</div>
</div>
<div class="menuitem">
<a title="" href="../Java/api.html">API Docs</a>
</div>
<div class="menuitem">
<a title="" href="../Java/interop.html">Interoperability</a>
</div>
<div class="menuitem">
<a title="" href="http://lsd.student.utwente.nl/gump/xml-security/xml-security.html">Gump results</a>
</div>
<div class="menuitem">
<a title="" href="../Java/resolver.html">Resolvermania</a>
</div>
</div>
<div id="credit"></div>
<div id="roundbottom">
<img style="display: none" class="corner" height="15" width="15" alt="" src="../skin/images/rc-b-l-15-1body-2menu-3menu.png"></div>
<!--+
|alternative credits
+-->
</div>
<!--+
|end Menu
+-->
<!--+
|start content
+-->
<div id="content">
<div id="skinconf-txtlink"></div>
<h1>Frequently Asked Questions - Java</h1>
<a name="N10008"></a><a name="Questions"></a>
<h2 class="h3">Questions</h2>
<div class="section">
<a name="N1000C"></a><a name="general_j"></a>
<h3 class="h4">1. Questions about Java</h3>
<a name="N10010"></a><a name="security_j"></a>
<h4 class="faq">1.1.
I have a Java-(security/cryptography) problem. Can you help me?
</h4>
<div align="right">
<a href="#security_j-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
Go to the <a class="external" href="http://forum.java.sun.com/">java forum</a> of Sun. You can
find forums where you can ask questions like "How do I generate
a keypair", etc.
</p>
</div>
<a name="N1001C"></a><a name="xml_j"></a>
<h4 class="faq">1.2.
I have a Java-XML problem.
</h4>
<div align="right">
<a href="#xml_j-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
Go to the <a class="external" href="http://forum.java.sun.com/">java forum</a> of Sun, section
Java Technology & XML and have a look at <a class="external" href="http://xml.apache.org/xerces2-j/index.html"> Apache Xerces</a>.
</p>
</div>
<a name="N1002C"></a><a name="specific_"></a>
<h3 class="h4">2. Questions about this package</h3>
<a name="N10030"></a><a name="crimson"></a>
<h4 class="faq">2.1.
I'm using Crimson, but it throws Exceptions. Why?
</h4>
<div align="right">
<a href="#crimson-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
Crimson is not supported at the moment. The main reason is that
Crimson did not support the
<span class="codefrag">org.w3c.dom.traversal.TreeWalker</span> interface in the
past. Additionally, it does not support the
<span class="codefrag">org.apache.xerces.dom.DocumentImpl.putIdentifier(String ID,
Element e)</span> functionality where Xerces allows us to enable ID
attributes during document generation.
</p>
<p>
Use <a class="external" href="http://xml.apache.org/xerces2-j/index.html">Apache Xerces</a>
instead of Crimson.
</p>
</div>
<a name="N10045"></a><a name="bouncy"></a>
<h4 class="faq">2.2.
What's up with the Bouncy Castle CSP? / Where is my CSP?
</h4>
<div align="right">
<a href="#bouncy-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
There is <em>no</em> JCE bundled together with this
distribution. This is because the Apache Project web site is hosted
in the US where some export restrictions apply to the cryptographic
primitives.
</p>
<p>
The nice guys from the <a class="external" href="http://www.bouncycastle.org/">Legion of Bouncy
Castle</a> where so helpful to supply their JCE in a simple JAR
package so that we can simply fetch it during the compilation process
and put it into the <span class="codefrag">libs/</span> directory. When you use the
ant makefile <span class="codefrag">build.xml</span> and simply say <span class="codefrag">ant
compile</span> or <span class="codefrag">ant get-jce</span>, <span class="codefrag">ant</span> tries
to fetch this JAR from the australian server. After that step, the
compilation works completely.
</p>
<p>
The ant make tools initiates an automated download of the
BouncyCastle JCE. The file is downloaded into the <span class="codefrag">libs/</span>
directory and a "bc-" is prepended to the filename. This is
done because we want the provider name (bc means BouncyCastle) being
visible in the JAR's filename.
</p>
<div class="frame note">
<div class="label">Note</div>
<div class="content">
The fact that we <em>use</em> Bouncy in this project does not mean
that you <em>must</em> use it, it's only the default. If you take a
look at the configuration
<span class="codefrag">src/org/apache/xml/security/resource/config.xml</span>, you'll
notice the sections which do integrate these alternative JCEs.
</div>
</div>
<p>
More information can be found in the <a href="../Java/installation.html">Installation</a> section.
</p>
</div>
<a name="N1007F"></a><a name="logging"></a>
<h4 class="faq">2.3.
How do I enable/turn off logging?
</h4>
<div align="right">
<a href="#logging-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
The logging is configured in the <span class="codefrag">config.xml</span> file which
either in the <span class="codefrag">xmlsec.jar</span> file or in the class path. This
is a little bit complicated as config.xml is used both for library
wide configurations like algorithms as well as for the user setting
about log4j. This will be changed someday ;-))
</p>
<p>OK, so it goes: In the
<a class="external" href="http://cvs.apache.org/viewcvs.cgi/xml-security/src/org/apache/xml/security/resource/config.xml?rev=HEAD&content-type=text/vnd.viewcvs-markup">
<span class="codefrag">xml-security/src/org/apache/xml/security/resource/config.xml</span>
</a> file, there is an element called
<span class="codefrag"><log4j:configuration></span>. This element contains the
XML style configuration information as defined in the
<a class="external" href="http://jakarta.apache.org/log4j/docs/api/org/apache/log4j/xml/DOMConfigurator.html">
log4j DOMConfigurator class
</a>. You can find examples
<a class="external" href="http://cvs.apache.org/viewcvs.cgi/jakarta-log4j/tests/input/xml/">here</a>
</p>
</div>
<a name="N100A2"></a><a name="baseURI"></a>
<h4 class="faq">2.4.
What is the meaning of BaseURI?
</h4>
<div align="right">
<a href="#baseURI-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
When you work with URIs like
"<span class="codefrag">http://www.example.com/index.html</span>", it is
quite sure what you mean as this is an absolute URL, i.e. it is clear
which protocol ise used to fetch which file from which server. When
you use such a URL inside a signature, the software can automatically
figure out what you sign. But when you sign something in your local
file system or if you use a relative path like
"<span class="codefrag">../1.txt</span>", it's not possible to understand
this reference without some context. <em>This</em> context is the
<span class="codefrag">BaseURI</span>. For instance, if you sign
<span class="codefrag">URI="../1.txt"</span> and the
<span class="codefrag">BaseURI="file:///home/user/work/signature.xml"</span>,
it is clear that the file
<span class="codefrag">BaseURI="file:///home/user/1.txt"</span> is to be
signed. But when you create the signature, the file
<span class="codefrag">BaseURI="file:///home/user/work/signature.xml"</span>
does not yet exist; therefore, you have to supply the URL where you
intend to store the signature later (relative to the signed objects).
</p>
<p>
The String BaseURI is the systemID on which the Object will be stored
in the future. This is needed to resolve relative links in the
<span class="codefrag">Reference</span> elements which point to the filesystem or
something similar.
</p>
<p>
Example: Imagine that you want to create a signature to store it on a
web server as
<span class="codefrag">http://www.acme.com/signatures/sig1.xml</span>. So
<span class="codefrag">BaseURI="http://www.acme.com/sig1.xml"</span>. This
means that if you create a <span class="codefrag">Reference</span> with
<span class="codefrag">URI="./index.html"</span>, the library can easily use
it's HTTPResourceResolver to fetch
<span class="codefrag">http://www.acme.com/index.html</span> without that you have to
say <span class="codefrag">URI="http://www.acme.com/index.html"</span>.
</p>
</div>
<a name="N100E0"></a><a name="examples"></a>
<h4 class="faq">2.5.
How do I use the package to generate and verify a signature?
</h4>
<div align="right">
<a href="#examples-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
Checkout the samples in
<span class="codefrag">src_samples/org/apache/xml/security/samples/signature/</span>.
</p>
<div class="frame note">
<div class="label">Note</div>
<div class="content">
The samples divide into two groups: Samples that <em>create</em> and
samples that <em>verify</em> Signatures. Eventually, you should
adjust the verifying program to another filename if you get
<span class="codefrag">FileNotFoundException</span>s.
</div>
</div>
</div>
<a name="N100F7"></a><a name="jdk140"></a>
<h4 class="faq">2.6.
I'm using SUN JDK v1.4.0 or v1.4.1 and it get some exceptions. Any clues?
</h4>
<div align="right">
<a href="#jdk140-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
After SUN released the <a class="external" href="http://java.sun.com/j2se/1.4/index.html"> Java (TM) 2 Platform
Standard Edition v1.4.0 </a>, the xml-security package stopped
working. This is a
<a class="external" href="http://developer.java.sun.com/developer/bugParade/bugs/4615582.html">
known
</a>
problem: SUN packaged a beta of Xalan into the JDK1.4.0, but the
xml-security package requires a stable version of Xalan (v2.2.0 or
later). To fix the problem, you have to put the xalan.jar into a
special directory in your JDK:
<span class="codefrag">j2sdk1.4.0/jre/lib/endorsed/xalan.jar</span>. If you installed
an out-of-the-box JDK1.4 (e.g. on Windows 2000), the
"endorsed" directory does not exist: you'll have to create
it by hand.
</p>
<div class="frame warning">
<div class="label">Warning</div>
<div class="content">Putting this JAR to another location like lib/ext WILL NOT WORK. </div>
</div>
<p>
For more on that, you can also check the <a class="external" href="http://xml.apache.org/~edwingo/jaxp-faq.html#override">
Unofficial JAXP FAQ </a>.
</p>
</div>
<a name="N10114"></a><a name="nullptrexception"></a>
<h4 class="faq">2.7.
I get a NullPointerException, and I don't know what's wrong.
</h4>
<div align="right">
<a href="#nullptrexception-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
Often, this problem is caused by using DOM1 calls like
<span class="codefrag">createElement(), setAttribute(), createAttribute()</span>. These are
non-namespace-aware and will cause XPath and C14N errors.
Always use the DOM2 <span class="codefrag">create(Attribute|Element)NS(...)</span>
methods instead, even if you're creating an element without a namespace
(in that case, you can use null as a namespace).
</p>
<p>
The Xalan-J Team told us that DOM1 calls are deprecated and are not to
be used in code. xml-security has been reviewed and is DOM1 clean now.
The Xalan folks told us that if you create Elements or attributes
using DOM1 calls which are not namespace aware, they do not care about
any problem you have because of incorrect hehaviour of Xalan.
</p>
</div>
<a name="N10125"></a><a name="elementorder"></a>
<h4 class="faq">2.8.
I sign a document and when I try to verify using the same key, it fails
</h4>
<div align="right">
<a href="#elementorder-menu">^</a>
</div>
<div style="margin-left: 15px">
<p>
After you have created the XMLSignature object, before you sign the
document, you <em>must</em> embed the signature element in the owning
document (using a call to <span class="codefrag">XMLSignature.getElement()</span> to
retrieve the newly created Element node from the signature) before
calling the <span class="codefrag">XMLSignature.sign()</span> method,
</p>
<p>
During canonicalisation of the SignedInfo element, the library looks
at the parent and ancestor nodes of the Signature element to find
any namespaces that the SignedInfo node has inherited. Any that are
found are embedded in the canonical form of the SignedInfo. (This
is not true when Exclusive Canonicalisation is used, but it is still
good practice to insert the element node prior to the sign()
method being called).
</p>
<p>
If you have not embedded the signature node in the document, it will
not have any parent or ancestor nodes, so it will not inherit their
namespaces. If you then embed it in the document and call <span class="codefrag">
verify()</span>, the namespaces will be found and the canonical
form of SignedInfo will be different to that generated during
<span class="codefrag">sign()</span>.
</p>
</div>
</div>
</div>
<!--+
|end content
+-->
<div class="clearboth"> </div>
</div>
<div id="footer">
<!--+
|start bottomstrip
+-->
<div class="lastmodified">
<script type="text/javascript"><!--
document.write("Last Published: " + document.lastModified);
// --></script>
</div>
<div class="copyright">
Copyright © 2002-2005 The Apache Software Foundation.</div>
<!--+
|end bottomstrip
+-->
</div>
</body>
</html>
|
