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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>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]50
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]51<P>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]52
53
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]54<P>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]55This module handles the OpenSSL pseudo random number generator (PRNG) and
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]56declares the following:
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]57
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]58<P>
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]59<dl><dt><b><a name='l2h-89'><tt class='function'>add</tt></a></b>(<var>string, entropy</var>)
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]60<dd>
61Mix bytes from <var>string</var> into the PRNG state. The <var>entropy</var> argument is
62(the lower bound of) an estimate of how much randomness is contained in
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]63<var>string</var>, measured in bytes. For more information, see e.g. <a class="rfc" name="rfcref-1858"
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]64href="http://www.ietf.org/rfc/rfc1750.txt">RFC 1750</a>.
65</dl>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]66
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]67<P>
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]68<dl><dt><b><a name='l2h-90'><tt class='function'>egd</tt></a></b>(<var>path</var><big>[</big><var>, bytes</var><big>]</big>)
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]69<dd>
70Query the Entropy Gathering Daemon<A NAME="tex2html3"
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]71 HREF="#foot956"><SUP>3</SUP></A> on socket <var>path</var> for <var>bytes</var>
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]72bytes of random data and and uses <tt class="function">add</tt> to seed the PRNG. The default
73value of <var>bytes</var> is 255.
74</dl>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]75
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]76<P>
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]77<dl><dt><b><a name='l2h-91'><tt class='function'>load_file</tt></a></b>(<var>path</var><big>[</big><var>, bytes</var><big>]</big>)
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]78<dd>
79Read <var>bytes</var> bytes (or all of it, if <var>bytes</var> is negative) of data from
80the file <var>path</var> to seed the PRNG. The default value of <var>bytes</var> is -1.
81</dl>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]82
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]83<P>
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]84<dl><dt><b><a name='l2h-92'><tt class='function'>screen</tt></a></b>()
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]85<dd>
86Add the current contents of the screen to the PRNG state.
87Availability: Windows.
88</dl>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]89
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]90<P>
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]91<dl><dt><b><a name='l2h-93'><tt class='function'>seed</tt></a></b>(<var>string</var>)
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]92<dd>
93This is equivalent to calling <tt class="function">add</tt> with <var>entropy</var> as the length
94of the string.
95</dl>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]96
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]97<P>
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]98<dl><dt><b><a name='l2h-94'><tt class='function'>status</tt></a></b>()
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]99<dd>
100Returns true if the PRNG has been seeded with enough data, and false otherwise.
101</dl>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]102
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]103<P>
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]104<dl><dt><b><a name='l2h-95'><tt class='function'>write_file</tt></a></b>(<var>path</var>)
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]105<dd>
106Write a number of random bytes (currently 1024) to the file <var>path</var>. This
107file can then be used with <tt class="function">load_file</tt> to seed the PRNG again.
108</dl>
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500[diff] [blame]109
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]110<P>
111<BR><HR><H4>Footnotes</H4>
112<DL>
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400[diff] [blame]113<DT><A NAME="foot956">... Daemon</A><A
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500[diff] [blame]114 href="openssl-rand.html#tex2html3"><SUP>3</SUP></A></DT>
115<DD>See
116<a class="url" href="http://www.lothar.com/tech/crypto/">http://www.lothar.com/tech/crypto/</a>
117
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