154 lines
6.0 KiB
HTML
Executable File
154 lines
6.0 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>BN_rand</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="#notes">NOTES</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="#history">HISTORY</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>BN_rand_ex, BN_rand, BN_priv_rand_ex, BN_priv_rand, BN_pseudo_rand,
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BN_rand_range_ex, BN_rand_range, BN_priv_rand_range_ex, BN_priv_rand_range,
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BN_pseudo_rand_range
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- generate pseudo-random number</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/bn.h></pre>
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<pre>
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int BN_rand_ex(BIGNUM *rnd, int bits, int top, int bottom, BN_CTX *ctx);
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int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);</pre>
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<pre>
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int BN_priv_rand_ex(BIGNUM *rnd, int bits, int top, int bottom, BN_CTX *ctx);
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int BN_priv_rand(BIGNUM *rnd, int bits, int top, int bottom);</pre>
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<pre>
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int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);</pre>
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<pre>
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int BN_rand_range_ex(BIGNUM *rnd, BIGNUM *range, BN_CTX *ctx);
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int BN_rand_range(BIGNUM *rnd, BIGNUM *range);</pre>
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<pre>
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int BN_priv_rand_range_ex(BIGNUM *rnd, BIGNUM *range, BN_CTX *ctx);
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int BN_priv_rand_range(BIGNUM *rnd, BIGNUM *range);</pre>
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<pre>
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int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range);</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><code>BN_rand_ex()</code> generate a cryptographically strong pseudo-random
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number of <strong>bits</strong> in length and stores it in <strong>rnd</strong> using the random number
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generator for the library context associated with <strong>ctx</strong>. The parameter <strong>ctx</strong>
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may be NULL in which case the default library context is used.
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If <strong>bits</strong> is less than zero, or too small to
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accommodate the requirements specified by the <strong>top</strong> and <strong>bottom</strong>
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parameters, an error is returned.
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The <strong>top</strong> parameters specifies
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requirements on the most significant bit of the generated number.
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If it is <strong>BN_RAND_TOP_ANY</strong>, there is no constraint.
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If it is <strong>BN_RAND_TOP_ONE</strong>, the top bit must be one.
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If it is <strong>BN_RAND_TOP_TWO</strong>, the two most significant bits of
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the number will be set to 1, so that the product of two such random
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numbers will always have 2*<strong>bits</strong> length.
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If <strong>bottom</strong> is <strong>BN_RAND_BOTTOM_ODD</strong>, the number will be odd; if it
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is <strong>BN_RAND_BOTTOM_ANY</strong> it can be odd or even.
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If <strong>bits</strong> is 1 then <strong>top</strong> cannot also be <strong>BN_RAND_FLG_TOPTWO</strong>.</p>
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<p><code>BN_rand()</code> is the same as <code>BN_rand_ex()</code> except that the default library context
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is always used.</p>
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<p><code>BN_rand_range_ex()</code> generates a cryptographically strong pseudo-random
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number <strong>rnd</strong> in the range 0 <= <strong>rnd</strong> < <strong>range</strong> using the random number
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generator for the library context associated with <strong>ctx</strong>. The parameter <strong>ctx</strong>
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may be NULL in which case the default library context is used.</p>
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<p><code>BN_rand_range()</code> is the same as <code>BN_rand_range_ex()</code> except that the default
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library context is always used.</p>
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<p><code>BN_priv_rand_ex()</code>, <code>BN_priv_rand()</code>, <code>BN_priv_rand_rand_ex()</code> and
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<code>BN_priv_rand_range()</code> have the same semantics as <code>BN_rand_ex()</code>, <code>BN_rand()</code>,
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<code>BN_rand_range_ex()</code> and <code>BN_rand_range()</code> respectively. They are intended to be
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used for generating values that should remain private, and mirror the
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same difference between <em>RAND_bytes(3)</em> and <em>RAND_priv_bytes(3)</em>.</p>
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<p>
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</p>
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<hr />
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<h1><a name="notes">NOTES</a></h1>
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<p>Always check the error return value of these functions and do not take
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randomness for granted: an error occurs if the CSPRNG has not been
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seeded with enough randomness to ensure an unpredictable byte sequence.</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>The functions return 1 on success, 0 on error.
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The error codes can be obtained by <em>ERR_get_error(3)</em>.</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>ERR_get_error(3)</em>,
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<em>RAND_add(3)</em>,
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<em>RAND_bytes(3)</em>,
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<em>RAND_priv_bytes(3)</em>,
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<em>RAND(7)</em>,
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<em>RAND_DRBG(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="history">HISTORY</a></h1>
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<ul>
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<li>
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<p>Starting with OpenSSL release 1.1.0, <code>BN_pseudo_rand()</code> has been identical
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to <code>BN_rand()</code> and <code>BN_pseudo_rand_range()</code> has been identical to
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<code>BN_rand_range()</code>.
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The "pseudo" functions should not be used and may be deprecated in
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a future release.</p>
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</li>
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<li>
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<p>The
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<code>BN_priv_rand()</code> and <code>BN_priv_rand_range()</code> functions were added in OpenSSL 1.1.1.</p>
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</li>
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<li>
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<p>The <code>BN_rand_ex()</code>, <code>BN_priv_rand_ex()</code>, <code>BN_rand_range_ex()</code> and
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<code>BN_priv_rand_range_ex()</code> functions were added in OpenSSL 3.0.</p>
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</li>
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</ul>
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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 2000-2019 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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