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<title>Gets the key size of the specified cipher</title>
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<div class="refnamediv">
<h1 class="refname">mcrypt_get_key_size</h1>
<p class="verinfo">(PHP 4, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0)</p><p class="refpurpose"><span class="refname">mcrypt_get_key_size</span> — <span class="dc-title">Gets the key size of the specified cipher</span></p>
</div>
<div id="function.mcrypt-get-key-size-refsynopsisdiv">
<div class="warning"><strong class="warning">Warning</strong><p class="simpara">This function has been
<em class="emphasis">DEPRECATED</em> as of PHP 7.1.0. Relying on this function
is highly discouraged.</p></div>
</div>
<div class="refsect1 description" id="refsect1-function.mcrypt-get-key-size-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">int</span> <span class="methodname"><strong>mcrypt_get_key_size</strong></span>
( <span class="methodparam"><span class="type">int</span> <code class="parameter">$cipher</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="type">int</span> <span class="methodname"><strong>mcrypt_get_key_size</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$cipher</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$mode</code></span>
)</div>
<p class="para rdfs-comment">
The first prototype is when linked against libmcrypt 2.2.x, the
second when linked against libmcrypt 2.4.x or 2.5.x.
</p>
<p class="para">
<span class="function"><strong>mcrypt_get_key_size()</strong></span> is used to get the size
of a key of the specified <code class="parameter">cipher</code> (in
combination with an encryption mode).
</p>
<p class="para">
It is more useful to use the <span class="function"><a href="function.mcrypt-enc-get-key-size.html" class="function">mcrypt_enc_get_key_size()</a></span>
function as this uses the resource returned by <span class="function"><a href="function.mcrypt-module-open.html" class="function">mcrypt_module_open()</a></span>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.mcrypt-get-key-size-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">cipher</code></dt>
<dd>
<p class="para">One of the <strong><code>MCRYPT_ciphername</code></strong> constants, or the name of the algorithm as string.</p>
</dd>
<dt>
<code class="parameter">mode</code></dt>
<dd>
<p class="para">One of the <strong><code>MCRYPT_MODE_modename</code></strong> constants, or one of the following strings: "ecb", "cbc", "cfb", "ofb", "nofb" or "stream".</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.mcrypt-get-key-size-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the maximum supported key size of the algorithm in bytes
or <strong><code>FALSE</code></strong> on failure.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.mcrypt-get-key-size-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-944">
<p><strong>Example #1 <span class="function"><strong>mcrypt_get_key_size()</strong></span> Example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /> </span><span style="color: #007700">echo </span><span style="color: #0000BB">mcrypt_get_key_size</span><span style="color: #007700">(</span><span style="color: #DD0000">'tripledes'</span><span style="color: #007700">, </span><span style="color: #DD0000">'ecb'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>
The example above shows how to use this function when
linked against libmcrypt 2.4.x or 2.5.x.
</p></div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
24
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.mcrypt-get-key-size-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.mcrypt-get-block-size.html" class="function" rel="rdfs-seeAlso">mcrypt_get_block_size()</a> - Gets the block size of the specified cipher</span></li>
<li class="member"><span class="function"><a href="function.mcrypt-enc-get-key-size.html" class="function" rel="rdfs-seeAlso">mcrypt_enc_get_key_size()</a> - Returns the maximum supported keysize of the opened mode</span></li>
<li class="member"><span class="function"><a href="function.mcrypt-encrypt.html" class="function" rel="rdfs-seeAlso">mcrypt_encrypt()</a> - Encrypts plaintext with given parameters</span></li>
</ul>
</p>
</div>
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