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gerrit-public.fairphone.software / platform / external / python / pyopenssl / 72b8f0fb39f1029de628e2c64bc00178b51baa90 / . / doc / html / openssl-rand.html
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46<H2><A NAME="SECTION000420000000000000000">&nbsp;</A>
47<BR>
483.2 <tt class="module">rand</tt> -- An interface to the OpenSSL pseudo random number generator
49</H2>
50<P>
51<EM><EM><EM>
52</EM></EM></EM>
53<P>
54<EM><EM><EM>This module handles the OpenSSL pseudo random number generator (PRNG) and
55declares the following:
56</EM></EM></EM>
57<P>
58<dl><dt><b><a name='l2h-82'><tt class='function'>add</tt></a></b>(<var>string, entropy</var>)
59<dd>
60Mix bytes from <var>string</var> into the PRNG state. The <var>entropy</var> argument is
61(the lower bound of) an estimate of how much randomness is contained in
Jean-Paul Calderone72b8f0f2008-02-21 23:57:40 -0500[diff] [blame^]62<var>string</var>, measured in bytes. For more information, see e.g. <a class="rfc" name="rfcref-1801"
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]63href="http://www.ietf.org/rfc/rfc1750.txt">RFC 1750</a>.
64</dl>
65<P>
66<dl><dt><b><a name='l2h-83'><tt class='function'>egd</tt></a></b>(<var>path</var><big>[</big><var>, bytes</var><big>]</big>)
67<dd>
68Query the Entropy Gathering Daemon<A NAME="tex2html3"
Jean-Paul Calderone72b8f0f2008-02-21 23:57:40 -0500[diff] [blame^]69 HREF="#foot916"><SUP>3</SUP></A> on socket <var>path</var> for <var>bytes</var>
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]70bytes of random data and and uses <tt class="function">add</tt> to seed the PRNG. The default
71value of <var>bytes</var> is 255.
72</dl>
73<P>
74<dl><dt><b><a name='l2h-84'><tt class='function'>load_file</tt></a></b>(<var>path</var><big>[</big><var>, bytes</var><big>]</big>)
75<dd>
76Read <var>bytes</var> bytes (or all of it, if <var>bytes</var> is negative) of data from
77the file <var>path</var> to seed the PRNG. The default value of <var>bytes</var> is -1.
78</dl>
79<P>
80<dl><dt><b><a name='l2h-85'><tt class='function'>screen</tt></a></b>()
81<dd>
82Add the current contents of the screen to the PRNG state.
83Availability: Windows.
84</dl>
85<P>
86<dl><dt><b><a name='l2h-86'><tt class='function'>seed</tt></a></b>(<var>string</var>)
87<dd>
88This is equivalent to calling <tt class="function">add</tt> with <var>entropy</var> as the length
89of the string.
90</dl>
91<P>
92<dl><dt><b><a name='l2h-87'><tt class='function'>status</tt></a></b>()
93<dd>
94Returns true if the PRNG has been seeded with enough data, and false otherwise.
95</dl>
96<P>
97<dl><dt><b><a name='l2h-88'><tt class='function'>write_file</tt></a></b>(<var>path</var>)
98<dd>
99Write a number of random bytes (currently 1024) to the file <var>path</var>. This
100file can then be used with <tt class="function">load_file</tt> to seed the PRNG again.
101</dl>
102<P>
103<BR><HR><H4>Footnotes</H4>
104<DL>
Jean-Paul Calderone72b8f0f2008-02-21 23:57:40 -0500[diff] [blame^]105<DT><A NAME="foot916">... Daemon</A><A
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]106 href="openssl-rand.html#tex2html3"><SUP>3</SUP></A></DT>
107<DD>See
108<a class="url" href="http://www.lothar.com/tech/crypto/">http://www.lothar.com/tech/crypto/</a>
109
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