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
|
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Decrypting an encrypted document</title>
<meta name="GENERATOR" content="Modular DocBook HTML Stylesheet Version 1.79">
<link rel="HOME" title="XML Security Library Reference Manual" href="index.html">
<link rel="UP" title="Verifing and decrypting documents." href="xmlsec-notes-verify-decrypt.html">
<link rel="PREVIOUS" title="Verifying a signed document" href="xmlsec-notes-verify.html">
<link rel="NEXT" title="Keys." href="xmlsec-notes-keys.html">
<style type="text/css">.synopsis, .classsynopsis {
background: #eeeeee;
border: solid 1px #aaaaaa;
padding: 0.5em;
}
.programlisting {
background: #eeeeff;
border: solid 1px #aaaaff;
padding: 0.5em;
}
.variablelist {
padding: 4px;
margin-left: 3em;
}
.navigation {
background: #ffeeee;
border: solid 1px #ffaaaa;
margin-top: 0.5em;
margin-bottom: 0.5em;
}
.navigation a {
color: #770000;
}
.navigation a:visited {
color: #550000;
}
.navigation .title {
font-size: 200%;
}</style>
<style type="text/css">
table.CALSTABLE > tbody > tr:nth-child(1) > td:nth-child(1) {
width: 20em;
}
.synopsis, .classsynopsis {
background: #eeeeee;
border: solid 1px #aaaaaa;
}
.programlisting {
background: #eeeeee;
border: solid 1px #000000;
}
.navigation {
background: #eeeeee;
border: solid 1px #000000;
}
.navigation a {
color: initial;
}
.navigation a:visited {
color: initial;
}
</style>
</head>
<body><table width="100%" valign="top"><tr valign="top">
<td valign="top" align="left" width="210">
<img src="../images/logo.gif" alt="XML Security Library" border="0"><p></p>
<ul>
<li><a href="../index.html">Home</a></li>
<li><a href="../download.html">Download</a></li>
<li><a href="../news.html">News</a></li>
<li><a href="../documentation.html">Documentation</a></li>
<ul>
<li><a href="../faq.html">FAQ</a></li>
<li><a href="../api/xmlsec-notes.html">Tutorial</a></li>
<li><a href="../api/xmlsec-reference.html">API reference</a></li>
<li><a href="../api/xmlsec-examples.html">Examples</a></li>
</ul>
<li><a href="../xmldsig.html">XML Digital Signature</a></li>
<ul><li><a href="http://www.aleksey.com/xmlsec/xmldsig-verifier.html">Online Verifier</a></li></ul>
<li><a href="../xmlenc.html">XML Encryption</a></li>
<li><a href="../c14n.html">XML Canonicalization</a></li>
<li><a href="../bugs.html">Reporting Bugs</a></li>
<li><a href="http://www.aleksey.com/pipermail/xmlsec">Mailing list</a></li>
<li><a href="../related.html">Related</a></li>
<li><a href="../authors.html">Authors</a></li>
</ul>
<table width="100%">
<tr>
<td width="15"></td>
<td><a href="http://xmlsoft.org/"><img src="../images/libxml2-logo.png" alt="LibXML2" border="0"></a></td>
</tr>
<tr>
<td width="15"></td>
<td><a href="http://xmlsoft.org/XSLT"><img src="../images/libxslt-logo.png" alt="LibXSLT" border="0"></a></td>
</tr>
<tr>
<td width="15"></td>
<td><a href="http://www.openssl.org/"><img src="../images/openssl-logo.png" alt="OpenSSL" border="0"></a></td>
</tr>
<!--Links - start--><!--Links - end-->
</table>
</td>
<td valign="top"><table width="100%" valign="top"><tr><td valign="top" align="left" id="xmlsecContent">
<table width="100%" class="navigation" summary="Navigation header" cellpadding="2" cellspacing="2"><tr valign="middle">
<td><a accesskey="p" href="xmlsec-notes-verify.html"><img src="left.png" width="16" height="16" border="0" alt="Prev"></a></td>
<td><a accesskey="u" href="xmlsec-notes-verify-decrypt.html"><img src="up.png" width="16" height="16" border="0" alt="Up"></a></td>
<td><a accesskey="h" href="index.html"><img src="home.png" width="16" height="16" border="0" alt="Home"></a></td>
<th width="100%" align="center">XML Security Library Reference Manual</th>
<td><a accesskey="n" href="xmlsec-notes-keys.html"><img src="right.png" width="16" height="16" border="0" alt="Next"></a></td>
</tr></table>
<br clear="all"><div class="SECT1">
<h1 class="SECT1"><a name="XMLSEC-NOTES-DECRYPT">Decrypting an encrypted document</a></h1>
<p>The typical decryption process includes following steps:
</p>
<p></p>
<ul>
<li><p> Load keys, X509 certificates, etc. in the <a href="xmlsec-keysmngr.html#XMLSECKEYSMNGR">keys manager</a> .
</p></li>
<li><p> Create encryption context <a href="xmlsec-xmlenc.html#XMLSECENCCTX">xmlSecEncCtx</a>
using <a href="xmlsec-xmlenc.html#XMLSECENCCTXCREATE">xmlSecEncCtxCreate</a> or
<a href="xmlsec-xmlenc.html#XMLSECENCCTXINITIALIZE">xmlSecEncCtxInitialize</a>
functions.
</p></li>
<li><p> Select start decryption <enc:EncryptedData> node.
</p></li>
<li><p> Decrypt by calling <a href="xmlsec-xmlenc.html#XMLSECENCCTXDECRYPT">xmlSecencCtxDecrypt</a>
function.
</p></li>
<li><p> Check returned value and if necessary consume encrypted data.
</p></li>
<li><p> Destroy encryption context <a href="xmlsec-xmlenc.html#XMLSECENCCTX">xmlSecEncCtx</a>
using <a href="xmlsec-xmlenc.html#XMLSECENCCTXDESTROY">xmlSecEncCtxDestroy</a> or
<a href="xmlsec-xmlenc.html#XMLSECENCCTXFINALIZE">xmlSecEncCtxFinalize</a>
functions.
</p></li>
</ul>
<p> </p>
<div class="EXAMPLE">
<a name="AEN396"></a><p><b>Example 2. Decrypting a document.</b></p>
<pre class="PROGRAMLISTING">int
decrypt_file(const char* enc_file, const char* key_file) {
xmlDocPtr doc = NULL;
xmlNodePtr node = NULL;
xmlSecEncCtxPtr encCtx = NULL;
int res = -1;
assert(enc_file);
assert(key_file);
/* load template */
doc = xmlParseFile(enc_file);
if ((doc == NULL) || (xmlDocGetRootElement(doc) == NULL)){
fprintf(stderr, "Error: unable to parse file \"%s\"\n", enc_file);
goto done;
}
/* find start node */
node = xmlSecFindNode(xmlDocGetRootElement(doc), xmlSecNodeEncryptedData, xmlSecEncNs);
if(node == NULL) {
fprintf(stderr, "Error: start node not found in \"%s\"\n", enc_file);
goto done;
}
/* create encryption context, we don't need keys manager in this example */
encCtx = xmlSecEncCtxCreate(NULL);
if(encCtx == NULL) {
fprintf(stderr,"Error: failed to create encryption context\n");
goto done;
}
/* load DES key */
encCtx->encKey = xmlSecKeyReadBinaryFile(xmlSecKeyDataDesId, key_file);
if(encCtx->encKey == NULL) {
fprintf(stderr,"Error: failed to load des key from binary file \"%s\"\n", key_file);
goto done;
}
/* set key name to the file name, this is just an example! */
if(xmlSecKeySetName(encCtx->encKey, key_file) < 0) {
fprintf(stderr,"Error: failed to set key name for key from \"%s\"\n", key_file);
goto done;
}
/* decrypt the data */
if((xmlSecEncCtxDecrypt(encCtx, node) < 0) || (encCtx->result == NULL)) {
fprintf(stderr,"Error: decryption failed\n");
goto done;
}
/* print decrypted data to stdout */
if(encCtx->resultReplaced != 0) {
fprintf(stdout, "Decrypted XML data:\n");
xmlDocDump(stdout, doc);
} else {
fprintf(stdout, "Decrypted binary data (%d bytes):\n", xmlSecBufferGetSize(encCtx->result));
if(xmlSecBufferGetData(encCtx->result) != NULL) {
fwrite(xmlSecBufferGetData(encCtx->result),
1,
xmlSecBufferGetSize(encCtx->result),
stdout);
}
}
fprintf(stdout, "\n");
/* success */
res = 0;
done:
/* cleanup */
if(encCtx != NULL) {
xmlSecEncCtxDestroy(encCtx);
}
if(doc != NULL) {
xmlFreeDoc(doc);
}
return(res);
}
</pre>
<p><a href="xmlsec-decrypt-with-signle-key.html#XMLSEC-EXAMPLE-DECRYPT1">Full Program Listing</a></p>
</div>
</div>
<table class="navigation" width="100%" summary="Navigation footer" cellpadding="2" cellspacing="2"><tr valign="middle">
<td align="left"><a accesskey="p" href="xmlsec-notes-verify.html"><b><<< Verifying a signed document</b></a></td>
<td align="right"><a accesskey="n" href="xmlsec-notes-keys.html"><b>Keys. >>></b></a></td>
</tr></table>
</td></tr></table></td>
</tr></table></body>
</html>
|