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132 lines
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132 lines
7.3 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>生成一个伪随机字节串</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.openssl-random-pseudo-bytes" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">openssl_random_pseudo_bytes</h1>
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<p class="verinfo">(PHP 5 >= 5.3.0, PHP 7)</p><p class="refpurpose"><span class="refname">openssl_random_pseudo_bytes</span> — <span class="dc-title">生成一个伪随机字节串</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.openssl-random-pseudo-bytes-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>openssl_random_pseudo_bytes</strong></span>
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( <span class="methodparam"><span class="type">int</span> <code class="parameter">$length</code></span>
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[, <span class="methodparam"><span class="type">bool</span> <code class="parameter reference">&$crypto_strong</code></span>
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] ) : <span class="type">string</span></div>
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<p class="para rdfs-comment">
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生成一个伪随机字节串 <span class="type"><a href="language.types.string.html" class="type string">string</a></span> ，字节数由 <code class="parameter">length</code> 参数指定。
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</p>
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<p class="para">
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通过 <code class="parameter">crypto_strong</code> 参数可以表示在生成随机字节的过程中是否使用了强加密算法。返回值为<strong><code>FALSE</code></strong>的情况很少见，但已损坏或老化的有些系统上会出现。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.openssl-random-pseudo-bytes-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">length</code></dt>
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<dd>
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<p class="para">
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所需字节串的长度，必须为正整数。PHP会试着将该参数转换为非空整数来使用它。
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</p>
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</dd>
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<dt>
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<code class="parameter">crypto_strong</code></dt>
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<dd>
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<p class="para">
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如果传递到该函数中，将会保存为一个 <span class="type"><a href="language.types.boolean.html" class="type boolean">boolean</a></span> 值来表明是否使用了“强加密”，如果被用于GPG和密码之类的将返回<strong><code>TRUE</code></strong> , 否则返回 <strong><code>FALSE</code></strong>
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</p>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.openssl-random-pseudo-bytes-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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成功，返回生成的字节串 <span class="type"><a href="language.types.string.html" class="type string">string</a></span> ， 或者在失败时返回 <strong><code>FALSE</code></strong>.
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.openssl-random-pseudo-bytes-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-943">
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<p><strong>Example #1 <span class="function"><strong>openssl_random_pseudo_bytes()</strong></span> 范例：</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">for (</span><span style="color: #0000BB">$i </span><span style="color: #007700">= -</span><span style="color: #0000BB">1</span><span style="color: #007700">; </span><span style="color: #0000BB">$i </span><span style="color: #007700"><= </span><span style="color: #0000BB">4</span><span style="color: #007700">; </span><span style="color: #0000BB">$i</span><span style="color: #007700">++) {<br /> </span><span style="color: #0000BB">$bytes </span><span style="color: #007700">= </span><span style="color: #0000BB">openssl_random_pseudo_bytes</span><span style="color: #007700">(</span><span style="color: #0000BB">$i</span><span style="color: #007700">, </span><span style="color: #0000BB">$cstrong</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$hex </span><span style="color: #007700">= </span><span style="color: #0000BB">bin2hex</span><span style="color: #007700">(</span><span style="color: #0000BB">$bytes</span><span style="color: #007700">);<br /><br /> echo </span><span style="color: #DD0000">"Lengths: Bytes: </span><span style="color: #0000BB">$i</span><span style="color: #DD0000"> and Hex: " </span><span style="color: #007700">. </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$hex</span><span style="color: #007700">) . </span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$hex</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$cstrong</span><span style="color: #007700">);<br /> echo </span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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<div class="example-contents"><p>以上例程的输出类似于：</p></div>
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<div class="example-contents screen">
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<div class="cdata"><pre>
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Lengths: Bytes: -1 and Hex: 0
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string(0) ""
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NULL
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Lengths: Bytes: 0 and Hex: 0
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string(0) ""
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NULL
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Lengths: Bytes: 1 and Hex: 2
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string(2) "42"
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bool(true)
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Lengths: Bytes: 2 and Hex: 4
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string(4) "dc6e"
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bool(true)
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Lengths: Bytes: 3 and Hex: 6
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string(6) "288591"
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bool(true)
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Lengths: Bytes: 4 and Hex: 8
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string(8) "ab86d144"
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bool(true)
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</pre></div>
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</div>
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</div>
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</p>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.openssl-random-pseudo-bytes-seealso">
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<h3 class="title">参见</h3>
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="random_bytes.html" class="function" rel="rdfs-seeAlso">random_bytes()</a> - Generates cryptographically secure pseudo-random bytes</span></li>
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<li class="member"><span class="function"><a href="bin2hex.html" class="function" rel="rdfs-seeAlso">bin2hex()</a> - 函数把包含数据的二进制字符串转换为十六进制值</span></li>
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<li class="member"><span class="function"><a href="crypt.html" class="function" rel="rdfs-seeAlso">crypt()</a> - 单向字符串散列</span></li>
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<li class="member"><span class="function"><a href="mt_rand.html" class="function" rel="rdfs-seeAlso">mt_rand()</a> - 生成更好的随机数</span></li>
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<li class="member"><span class="function"><a href="uniqid.html" class="function" rel="rdfs-seeAlso">uniqid()</a> - 生成一个唯一ID</span></li>
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</ul>
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</div>
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</div></div></div></body></html> |