This file is indexed.

/usr/share/doc/python-crypto-doc/Crypto.Cipher.ARC2-module.html is in python-crypto-doc 2.6.1-4ubuntu0.3.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
<?xml version="1.0" encoding="ascii"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
          "DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
  <title>Crypto.Cipher.ARC2</title>
  <link rel="stylesheet" href="epydoc.css" type="text/css" />
  <script type="text/javascript" src="epydoc.js"></script>
</head>

<body bgcolor="white" text="black" link="blue" vlink="#204080"
      alink="#204080">
<!-- ==================== NAVIGATION BAR ==================== -->
<table class="navbar" border="0" width="100%" cellpadding="0"
       bgcolor="#a0c0ff" cellspacing="0">
  <tr valign="middle">
  <!-- Home link -->
      <th>&nbsp;&nbsp;&nbsp;<a
        href="Crypto-module.html">Home</a>&nbsp;&nbsp;&nbsp;</th>

  <!-- Tree link -->
      <th>&nbsp;&nbsp;&nbsp;<a
        href="module-tree.html">Trees</a>&nbsp;&nbsp;&nbsp;</th>

  <!-- Index link -->
      <th>&nbsp;&nbsp;&nbsp;<a
        href="identifier-index.html">Indices</a>&nbsp;&nbsp;&nbsp;</th>

  <!-- Help link -->
      <th>&nbsp;&nbsp;&nbsp;<a
        href="help.html">Help</a>&nbsp;&nbsp;&nbsp;</th>

  <!-- Project homepage -->
      <th class="navbar" align="right" width="100%">
        <table border="0" cellpadding="0" cellspacing="0">
          <tr><th class="navbar" align="center"
            ><a href="http://www.pycrypto.org/">PyCrypto.org</a></th>
          </tr></table></th>
  </tr>
</table>
<table width="100%" cellpadding="0" cellspacing="0">
  <tr valign="top">
    <td width="100%">
      <span class="breadcrumbs">
        <a href="Crypto-module.html">Package&nbsp;Crypto</a> ::
        <a href="Crypto.Cipher-module.html">Package&nbsp;Cipher</a> ::
        Module&nbsp;ARC2
      </span>
    </td>
    <td>
      <table cellpadding="0" cellspacing="0">
        <!-- hide/show private -->
        <tr><td align="right"><span class="options"
            >[<a href="frames.html" target="_top">frames</a
            >]&nbsp;|&nbsp;<a href="Crypto.Cipher.ARC2-module.html"
            target="_top">no&nbsp;frames</a>]</span></td></tr>
      </table>
    </td>
  </tr>
</table>
<!-- ==================== MODULE DESCRIPTION ==================== -->
<h1 class="epydoc">Module ARC2</h1><p class="nomargin-top"></p>
<p>RC2 symmetric cipher</p>
<p><a class="rst-reference external" href="http://en.wikipedia.org/wiki/RC2" target="_top">RC2</a> (Rivest's Cipher version 2)  is a symmetric block cipher designed
by Ron Rivest in 1987. The cipher started as a proprietary design,
that was reverse engineered and anonymously posted on Usenet in 1996.
For this reason, the algorithm was first called <em>Alleged</em> RC2 (ARC2),
since the company that owned RC2 (RSA Data Inc.) did not confirm whether
the details leaked into public domain were really correct.</p>
<p>The company eventually published its full specification in <a class="rst-reference external" href="http://tools.ietf.org/html/rfc2268" target="_top">RFC2268</a>.</p>
<p>RC2 has a fixed data block size of 8 bytes. Length of its keys can vary from
8 to 128 bits. One particular property of RC2 is that the actual
cryptographic strength of the key (<em>effective key length</em>) can be reduced
via a parameter.</p>
<p>Even though RC2 is not cryptographically broken, it has not been analyzed as
thoroughly as AES, which is also faster than RC2.</p>
<p>New designs should not use RC2.</p>
<p>As an example, encryption can be done as follows:</p>
<blockquote>
<pre class="py-doctest">
<span class="py-prompt">&gt;&gt;&gt; </span><span class="py-keyword">from</span> Crypto.Cipher <span class="py-keyword">import</span> ARC2
<span class="py-prompt">&gt;&gt;&gt; </span><span class="py-keyword">from</span> Crypto <span class="py-keyword">import</span> Random
<span class="py-prompt">&gt;&gt;&gt;</span>
<span class="py-prompt">&gt;&gt;&gt; </span>key = b<span class="py-string">'Sixteen byte key'</span>
<span class="py-prompt">&gt;&gt;&gt; </span>iv = Random.new().read(ARC2.block_size)
<span class="py-prompt">&gt;&gt;&gt; </span>cipher = ARC2.new(key, ARC2.MODE_CFB, iv)
<span class="py-prompt">&gt;&gt;&gt; </span>msg = iv + cipher.encrypt(b<span class="py-string">'Attack at dawn'</span>)</pre>
</blockquote>

<!-- ==================== CLASSES ==================== -->
<a name="section-Classes"></a>
<table class="summary" border="1" cellpadding="3"
       cellspacing="0" width="100%" bgcolor="white">
<tr bgcolor="#70b0f0" class="table-header">
  <td align="left" colspan="2" class="table-header">
    <span class="table-header">Classes</span></td>
</tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a href="Crypto.Cipher.ARC2.RC2Cipher-class.html" class="summary-name">RC2Cipher</a><br />
      RC2 cipher object
    </td>
  </tr>
</table>
<!-- ==================== FUNCTIONS ==================== -->
<a name="section-Functions"></a>
<table class="summary" border="1" cellpadding="3"
       cellspacing="0" width="100%" bgcolor="white">
<tr bgcolor="#70b0f0" class="table-header">
  <td align="left" colspan="2" class="table-header">
    <span class="table-header">Functions</span></td>
</tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
      <table width="100%" cellpadding="0" cellspacing="0" border="0">
        <tr>
          <td><span class="summary-sig"><a href="Crypto.Cipher.ARC2-module.html#new" class="summary-sig-name">new</a>(<span class="summary-sig-arg">key</span>,
        <span class="summary-sig-arg">*args</span>,
        <span class="summary-sig-arg">**kwargs</span>)</span><br />
      Create a new RC2 cipher</td>
          <td align="right" valign="top">
            
            
          </td>
        </tr>
      </table>
      
    </td>
  </tr>
</table>
<!-- ==================== VARIABLES ==================== -->
<a name="section-Variables"></a>
<table class="summary" border="1" cellpadding="3"
       cellspacing="0" width="100%" bgcolor="white">
<tr bgcolor="#70b0f0" class="table-header">
  <td align="left" colspan="2" class="table-header">
    <span class="table-header">Variables</span></td>
</tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="MODE_ECB"></a><span class="summary-name">MODE_ECB</span> = <code title="1">1</code><br />
      Electronic Code Book (ECB). See <a href="Crypto.Cipher.blockalgo-module.html#MODE_ECB" class="link">blockalgo.MODE_ECB</a>.
    </td>
  </tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="MODE_CBC"></a><span class="summary-name">MODE_CBC</span> = <code title="2">2</code><br />
      Cipher-Block Chaining (CBC). See <a href="Crypto.Cipher.blockalgo-module.html#MODE_CBC" class="link">blockalgo.MODE_CBC</a>.
    </td>
  </tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="MODE_CFB"></a><span class="summary-name">MODE_CFB</span> = <code title="3">3</code><br />
      Cipher FeedBack (CFB). See <a href="Crypto.Cipher.blockalgo-module.html#MODE_CFB" class="link">blockalgo.MODE_CFB</a>.
    </td>
  </tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="MODE_PGP"></a><span class="summary-name">MODE_PGP</span> = <code title="4">4</code><br />
      This mode should not be used.
    </td>
  </tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="MODE_OFB"></a><span class="summary-name">MODE_OFB</span> = <code title="5">5</code><br />
      Output FeedBack (OFB). See <a href="Crypto.Cipher.blockalgo-module.html#MODE_OFB" class="link">blockalgo.MODE_OFB</a>.
    </td>
  </tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="MODE_CTR"></a><span class="summary-name">MODE_CTR</span> = <code title="6">6</code><br />
      CounTer Mode (CTR). See <a href="Crypto.Cipher.blockalgo-module.html#MODE_CTR" class="link">blockalgo.MODE_CTR</a>.
    </td>
  </tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="MODE_OPENPGP"></a><span class="summary-name">MODE_OPENPGP</span> = <code title="7">7</code><br />
      OpenPGP Mode. See <a href="Crypto.Cipher.blockalgo-module.html#MODE_OPENPGP" class="link">blockalgo.MODE_OPENPGP</a>.
    </td>
  </tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="block_size"></a><span class="summary-name">block_size</span> = <code title="8">8</code><br />
      Size of a data block (in bytes)
    </td>
  </tr>
<tr>
    <td width="15%" align="right" valign="top" class="summary">
      <span class="summary-type">&nbsp;</span>
    </td><td class="summary">
        <a name="key_size"></a><span class="summary-name">key_size</span> = <code title="xrange(1, 17)">xrange(1, 17)</code><br />
      Size of a key (in bytes)
    </td>
  </tr>
</table>
<!-- ==================== FUNCTION DETAILS ==================== -->
<a name="section-FunctionDetails"></a>
<table class="details" border="1" cellpadding="3"
       cellspacing="0" width="100%" bgcolor="white">
<tr bgcolor="#70b0f0" class="table-header">
  <td align="left" colspan="2" class="table-header">
    <span class="table-header">Function Details</span></td>
</tr>
</table>
<a name="new"></a>
<div>
<table class="details" border="1" cellpadding="3"
       cellspacing="0" width="100%" bgcolor="white">
<tr><td>
  <table width="100%" cellpadding="0" cellspacing="0" border="0">
  <tr valign="top"><td>
  <h3 class="epydoc"><span class="sig"><span class="sig-name">new</span>(<span class="sig-arg">key</span>,
        <span class="sig-arg">*args</span>,
        <span class="sig-arg">**kwargs</span>)</span>
  </h3>
  </td><td align="right" valign="top"
    >&nbsp;
    </td>
  </tr></table>
  
  Create a new RC2 cipher
  <dl class="fields">
    <dt>Parameters:</dt>
    <dd><ul class="nomargin-top">
        <li><strong class="pname"><code>key</code></strong> (byte string) - The secret key to use in the symmetric cipher.
Its length can vary from 1 to 128 bytes.</li>
        <li><strong class="pname"><code>mode</code></strong> (a <em>MODE_*</em> constant) - The chaining mode to use for encryption or decryption.
Default is <a href="Crypto.Cipher.ARC2-module.html#MODE_ECB" class="link">MODE_ECB</a>.</li>
        <li><p><strong class="pname"><code>IV</code></strong> (byte string) - The initialization vector to use for encryption or decryption.</p>
<p>It is ignored for <a href="Crypto.Cipher.ARC2-module.html#MODE_ECB" class="link">MODE_ECB</a> and <a href="Crypto.Cipher.ARC2-module.html#MODE_CTR" class="link">MODE_CTR</a>.</p>
<p>For <a href="Crypto.Cipher.ARC2-module.html#MODE_OPENPGP" class="link">MODE_OPENPGP</a>, IV must be <a href="Crypto.Cipher.ARC2-module.html#block_size" class="link">block_size</a> bytes long for encryption
and <a href="Crypto.Cipher.ARC2-module.html#block_size" class="link">block_size</a> +2 bytes for decryption (in the latter case, it is
actually the <em>encrypted</em> IV which was prefixed to the ciphertext).
It is mandatory.</p>
<p>For all other modes, it must be <a href="Crypto.Cipher.ARC2-module.html#block_size" class="link">block_size</a> bytes longs.</p></li>
        <li><strong class="pname"><code>counter</code></strong> (callable) - (<em>Only</em> <a href="Crypto.Cipher.ARC2-module.html#MODE_CTR" class="link">MODE_CTR</a>). A stateful function that returns the next
<em>counter block</em>, which is a byte string of <a href="Crypto.Cipher.ARC2-module.html#block_size" class="link">block_size</a> bytes.
For better performance, use <a href="Crypto.Util.Counter-module.html" class="link">Crypto.Util.Counter</a>.</li>
        <li><strong class="pname"><code>segment_size</code></strong> (integer) - (<em>Only</em> <a href="Crypto.Cipher.ARC2-module.html#MODE_CFB" class="link">MODE_CFB</a>).The number of bits the plaintext and ciphertext
are segmented in.
It must be a multiple of 8. If 0 or not specified, it will be assumed to be 8.</li>
        <li><strong class="pname"><code>effective_keylen</code></strong> (integer) - Maximum cryptographic strength of the key, in bits.
It can vary from 0 to 1024. The default value is 1024.</li>
    </ul></dd>
    <dt>Returns:</dt>
        <dd>an <a href="Crypto.Cipher.ARC2.RC2Cipher-class.html" class="link">RC2Cipher</a> object</dd>
  </dl>
</td></tr></table>
</div>
<br />
<!-- ==================== NAVIGATION BAR ==================== -->
<table class="navbar" border="0" width="100%" cellpadding="0"
       bgcolor="#a0c0ff" cellspacing="0">
  <tr valign="middle">
  <!-- Home link -->
      <th>&nbsp;&nbsp;&nbsp;<a
        href="Crypto-module.html">Home</a>&nbsp;&nbsp;&nbsp;</th>

  <!-- Tree link -->
      <th>&nbsp;&nbsp;&nbsp;<a
        href="module-tree.html">Trees</a>&nbsp;&nbsp;&nbsp;</th>

  <!-- Index link -->
      <th>&nbsp;&nbsp;&nbsp;<a
        href="identifier-index.html">Indices</a>&nbsp;&nbsp;&nbsp;</th>

  <!-- Help link -->
      <th>&nbsp;&nbsp;&nbsp;<a
        href="help.html">Help</a>&nbsp;&nbsp;&nbsp;</th>

  <!-- Project homepage -->
      <th class="navbar" align="right" width="100%">
        <table border="0" cellpadding="0" cellspacing="0">
          <tr><th class="navbar" align="center"
            ><a href="http://www.pycrypto.org/">PyCrypto.org</a></th>
          </tr></table></th>
  </tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" width="100%%">
  <tr>
    <td align="left" class="footer">
    Generated by Epydoc 3.0.1 on Fri Mar 30 15:40:57 2018
    </td>
    <td align="right" class="footer">
      <a target="mainFrame" href="http://epydoc.sourceforge.net"
        >http://epydoc.sourceforge.net</a>
    </td>
  </tr>
</table>

<script type="text/javascript">
  <!--
  // Private objects are initially displayed (because if
  // javascript is turned off then we want them to be
  // visible); but by default, we want to hide them.  So hide
  // them unless we have a cookie that says to show them.
  checkCookie();
  // -->
</script>
</body>
</html>