/usr/share/doc/python-crypto-doc/Crypto.Protocol.Chaffing.Chaff-class.html is in python-crypto-doc 2.6.1-6build1.
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 | <?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.Protocol.Chaffing.Chaff</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> <a
href="Crypto-module.html">Home</a> </th>
<!-- Tree link -->
<th> <a
href="module-tree.html">Trees</a> </th>
<!-- Index link -->
<th> <a
href="identifier-index.html">Indices</a> </th>
<!-- Help link -->
<th> <a
href="help.html">Help</a> </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 Crypto</a> ::
<a href="Crypto.Protocol-module.html">Package Protocol</a> ::
<a href="Crypto.Protocol.Chaffing-module.html">Module Chaffing</a> ::
Class Chaff
</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
>] | <a href="Crypto.Protocol.Chaffing.Chaff-class.html"
target="_top">no frames</a>]</span></td></tr>
</table>
</td>
</tr>
</table>
<!-- ==================== CLASS DESCRIPTION ==================== -->
<h1 class="epydoc">Class Chaff</h1><p class="nomargin-top"></p>
<p>Class implementing the chaff adding algorithm.</p>
<p>Methods for subclasses:</p>
<blockquote>
<dl class="rst-docutils">
<dt>_randnum(size):</dt>
<dd>Returns a randomly generated number with a byte-length equal
to size. Subclasses can use this to implement better random
data and MAC generating algorithms. The default algorithm is
probably not very cryptographically secure. It is most
important that the chaff data does not contain any patterns
that can be used to discern it from wheat data without running
the MAC.</dd>
</dl>
</blockquote>
<!-- ==================== INSTANCE METHODS ==================== -->
<a name="section-InstanceMethods"></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">Instance Methods</span></td>
</tr>
<tr>
<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
</td><td class="summary">
<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td><span class="summary-sig"><a href="Crypto.Protocol.Chaffing.Chaff-class.html#__init__" class="summary-sig-name">__init__</a>(<span class="summary-sig-arg">self</span>,
<span class="summary-sig-arg">factor</span>=<span class="summary-sig-default">1.0</span>,
<span class="summary-sig-arg">blocksper</span>=<span class="summary-sig-default">1</span>)</span><br />
Chaff(factor:float, blocksper:int)</td>
<td align="right" valign="top">
</td>
</tr>
</table>
</td>
</tr>
<tr>
<td width="15%" align="right" valign="top" class="summary">
<span class="summary-type"> </span>
</td><td class="summary">
<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td><span class="summary-sig"><a href="Crypto.Protocol.Chaffing.Chaff-class.html#chaff" class="summary-sig-name">chaff</a>(<span class="summary-sig-arg">self</span>,
<span class="summary-sig-arg">blocks</span>)</span><br />
chaff( [(serial-number:int, data:string, MAC:string)] )
: [(int, string, string)]</td>
<td align="right" valign="top">
</td>
</tr>
</table>
</td>
</tr>
</table>
<!-- ==================== METHOD DETAILS ==================== -->
<a name="section-MethodDetails"></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">Method Details</span></td>
</tr>
</table>
<a name="__init__"></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">__init__</span>(<span class="sig-arg">self</span>,
<span class="sig-arg">factor</span>=<span class="sig-default">1.0</span>,
<span class="sig-arg">blocksper</span>=<span class="sig-default">1</span>)</span>
<br /><em class="fname">(Constructor)</em>
</h3>
</td><td align="right" valign="top"
>
</td>
</tr></table>
<p>Chaff(factor:float, blocksper:int)</p>
<p>factor is the number of message blocks to add chaff to,
expressed as a percentage between 0.0 and 1.0. blocksper is
the number of chaff blocks to include for each block being
chaffed. Thus the defaults add one chaff block to every
message block. By changing the defaults, you can adjust how
computationally difficult it could be for an adversary to
brute-force crack the message. The difficulty is expressed
as:</p>
<blockquote>
pow(blocksper, int(factor * number-of-blocks))</blockquote>
<p>For ease of implementation, when factor < 1.0, only the first
int(factor*number-of-blocks) message blocks are chaffed.</p>
<dl class="fields">
</dl>
</td></tr></table>
</div>
<a name="chaff"></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">chaff</span>(<span class="sig-arg">self</span>,
<span class="sig-arg">blocks</span>)</span>
</h3>
</td><td align="right" valign="top"
>
</td>
</tr></table>
<p>chaff( [(serial-number:int, data:string, MAC:string)] )
: [(int, string, string)]</p>
<p>Add chaff to message blocks. blocks is a list of 3-tuples of the
form (serial-number, data, MAC).</p>
<p>Chaff is created by choosing a random number of the same
byte-length as data, and another random number of the same
byte-length as MAC. The message block's serial number is
placed on the chaff block and all the packet's chaff blocks
are randomly interspersed with the single wheat block. This
method then returns a list of 3-tuples of the same form.
Chaffed blocks will contain multiple instances of 3-tuples
with the same serial number, but the only way to figure out
which blocks are wheat and which are chaff is to perform the
MAC hash and compare values.</p>
<dl class="fields">
</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> <a
href="Crypto-module.html">Home</a> </th>
<!-- Tree link -->
<th> <a
href="module-tree.html">Trees</a> </th>
<!-- Index link -->
<th> <a
href="identifier-index.html">Indices</a> </th>
<!-- Help link -->
<th> <a
href="help.html">Help</a> </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 Mon Jan 18 19:39:43 2016
</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>
|