95 lines
3.5 KiB
HTML
Executable File
95 lines
3.5 KiB
HTML
Executable File
<?xml version="1.0" ?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<title>RAND_egd</title>
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<meta http-equiv="content-type" content="text/html; charset=utf-8" />
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<link rev="made" href="mailto:root@localhost" />
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</head>
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<body style="background-color: white">
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<!-- INDEX BEGIN -->
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<div name="index">
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<p><a name="__index__"></a></p>
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<ul>
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<li><a href="#name">NAME</a></li>
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<li><a href="#synopsis">SYNOPSIS</a></li>
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<li><a href="#description">DESCRIPTION</a></li>
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<li><a href="#return_values">RETURN VALUES</a></li>
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<li><a href="#see_also">SEE ALSO</a></li>
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<li><a href="#copyright">COPYRIGHT</a></li>
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</ul>
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<hr name="index" />
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</div>
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<!-- INDEX END -->
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<p>
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</p>
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<hr />
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<h1><a name="name">NAME</a></h1>
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<p>RAND_egd, RAND_egd_bytes, RAND_query_egd_bytes - query entropy gathering daemon</p>
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<p>
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</p>
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<hr />
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<h1><a name="synopsis">SYNOPSIS</a></h1>
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<pre>
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#include <openssl/rand.h></pre>
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<pre>
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int RAND_egd_bytes(const char *path, int num);
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int RAND_egd(const char *path);</pre>
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<pre>
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int RAND_query_egd_bytes(const char *path, unsigned char *buf, int num);</pre>
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<p>
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</p>
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<hr />
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<h1><a name="description">DESCRIPTION</a></h1>
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<p>On older platforms without a good source of randomness such as <code>/dev/urandom</code>,
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it is possible to query an Entropy Gathering Daemon (EGD) over a local
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socket to obtain randomness and seed the OpenSSL RNG.
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The protocol used is defined by the EGDs available at
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<a href="http://egd.sourceforge.net/">http://egd.sourceforge.net/</a> or <a href="http://prngd.sourceforge.net">http://prngd.sourceforge.net</a>.</p>
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<p><code>RAND_egd_bytes()</code> requests <strong>num</strong> bytes of randomness from an EGD at the
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specified socket <strong>path</strong>, and passes the data it receives into <code>RAND_add()</code>.
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<code>RAND_egd()</code> is equivalent to <code>RAND_egd_bytes()</code> with <strong>num</strong> set to 255.</p>
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<p><code>RAND_query_egd_bytes()</code> requests <strong>num</strong> bytes of randomness from an EGD at
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the specified socket <strong>path</strong>, where <strong>num</strong> must be less than 256.
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If <strong>buf</strong> is <strong>NULL</strong>, it is equivalent to <code>RAND_egd_bytes()</code>.
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If <strong>buf</strong> is not <strong>NULL</strong>, then the data is copied to the buffer and
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<code>RAND_add()</code> is not called.</p>
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<p>OpenSSL can be configured at build time to try to use the EGD for seeding
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automatically.</p>
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<p>
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</p>
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<hr />
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<h1><a name="return_values">RETURN VALUES</a></h1>
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<p><code>RAND_egd()</code> and <code>RAND_egd_bytes()</code> return the number of bytes read from the
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daemon on success, or -1 if the connection failed or the daemon did not
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return enough data to fully seed the PRNG.</p>
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<p><code>RAND_query_egd_bytes()</code> returns the number of bytes read from the daemon on
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success, or -1 if the connection failed.</p>
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<p>
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</p>
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<hr />
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<h1><a name="see_also">SEE ALSO</a></h1>
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<p><em>RAND_add(3)</em>,
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<em>RAND_bytes(3)</em>,
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<em>RAND(7)</em></p>
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<p>
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</p>
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<hr />
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<h1><a name="copyright">COPYRIGHT</a></h1>
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<p>Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.</p>
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<p>Licensed under the Apache License 2.0 (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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<a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>
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</body>
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</html>
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