function.mcrypt-generic.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>This function encrypts data</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.mcrypt-generic-init.html">mcrypt_generic_init</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.mcrypt-get-block-size.html">mcrypt_get_block_size</a></div> <div class="up"><a href="ref.mcrypt.html">Mcrypt Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.mcrypt-generic" class="refentry"> <div class="refnamediv"> <h1 class="refname">mcrypt_generic</h1> <p class="verinfo">(PHP 4 >= 4.0.2, PHP 5)</p><p class="refpurpose"><span class="refname">mcrypt_generic</span> — <span class="dc-title">This function encrypts data</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">string</span> <span class="methodname"><b><b>mcrypt_generic</b></b></span> ( <span class="methodparam"><span class="type">resource</span> <tt class="parameter">$td</tt></span> , <span class="methodparam"><span class="type">string</span> <tt class="parameter">$data</tt></span> )</div> <p class="para rdfs-comment"> This function encrypts data. The data is padded with "<i>\0</i>" to make sure the length of the data is n * blocksize. This function returns the encrypted data. Note that the length of the returned string can in fact be longer then the input, due to the padding of the data. </p> <p class="para"> If you want to store the encrypted data in a database make sure to store the entire string as returned by mcrypt_generic, or the string will not entirely decrypt properly. If your original string is 10 characters long and the block size is 8 (use <a href="function.mcrypt-enc-get-block-size.html" class="function">mcrypt_enc_get_block_size()</a> to determine the blocksize), you would need at least 16 characters in your database field. Note the string returned by <a href="function.mdecrypt-generic.html" class="function">mdecrypt_generic()</a> will be 16 characters as well...use rtrim($str, "\0") to remove the padding. </p> <p class="para"> If you are for example storing the data in a MySQL database remember that varchar fields automatically have trailing spaces removed during insertion. As encrypted data can end in a space (ASCII 32), the data will be damaged by this removal. Store data in a tinyblob/tinytext (or larger) field instead. </p> <p class="para"> The encryption handle should always be initialized with <a href="function.mcrypt-generic-init.html" class="function">mcrypt_generic_init()</a> with a key and an IV before calling this function. Where the encryption is done, you should free the encryption buffers by calling <a href="function.mcrypt-generic-deinit.html" class="function">mcrypt_generic_deinit()</a>. See <a href="function.mcrypt-module-open.html" class="function">mcrypt_module_open()</a> for an example. </p> <p class="para"> See also <a href="function.mdecrypt-generic.html" class="function">mdecrypt_generic()</a>, <a href="function.mcrypt-generic-init.html" class="function">mcrypt_generic_init()</a>, and <a href="function.mcrypt-generic-deinit.html" class="function">mcrypt_generic_deinit()</a>. </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.mcrypt-generic-init.html">mcrypt_generic_init</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.mcrypt-get-block-size.html">mcrypt_get_block_size</a></div> <div class="up"><a href="ref.mcrypt.html">Mcrypt Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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