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<title>Generate a keyed hash value using the HMAC method</title>
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<h1 class="refname">hash_hmac</h1>
<p class="verinfo">(PHP 5 >= 5.1.2, PECL hash >= 1.1)</p><p class="refpurpose"><span class="refname">hash_hmac</span> — <span class="dc-title">Generate a keyed hash value using the HMAC method</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.hash-hmac-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">string</span> <span class="methodname"><strong>hash_hmac</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$algo</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$data</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$key</code></span>
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$raw_output</code><span class="initializer"> = false</span></span>
] )</div>
</div>
<div class="refsect1 parameters" id="refsect1-function.hash-hmac-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">algo</code></em></span>
<dd>
<p class="para">
Name of selected hashing algorithm (i.e. "md5", "sha256", "haval160,4", etc..) See <span class="function"><a href="function.hash-algos.html" class="function">hash_algos()</a></span> for a list of supported algorithms.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">data</code></em></span>
<dd>
<p class="para">
Message to be hashed.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">key</code></em></span>
<dd>
<p class="para">
Shared secret key used for generating the HMAC variant of the message digest.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">raw_output</code></em></span>
<dd>
<p class="para">
When set to <strong><code>TRUE</code></strong>, outputs raw binary data.
<strong><code>FALSE</code></strong> outputs lowercase hexits.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.hash-hmac-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns a string containing the calculated message digest as lowercase hexits
unless <em><code class="parameter">raw_output</code></em> is set to true in which case the raw
binary representation of the message digest is returned.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.hash-hmac-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-833">
<p><strong>Example #1 <span class="function"><strong>hash_hmac()</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">hash_hmac</span><span style="color: #007700">(</span><span style="color: #DD0000">'ripemd160'</span><span style="color: #007700">, </span><span style="color: #DD0000">'The quick brown fox jumped over the lazy dog.'</span><span style="color: #007700">, </span><span style="color: #DD0000">'secret'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
b8e7ae12510bdfb1812e463a7f086122cf37e4f7
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.hash-hmac-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.hash.html" class="function" rel="rdfs-seeAlso">hash()</a> - Generate a hash value (message digest)</span></li>
<li class="member"> <span class="function"><a href="function.hash-algos.html" class="function" rel="rdfs-seeAlso">hash_algos()</a> - Return a list of registered hashing algorithms</span></li>
<li class="member"> <span class="function"><a href="function.hash-init.html" class="function" rel="rdfs-seeAlso">hash_init()</a> - Initialize an incremental hashing context</span></li>
<li class="member"> <span class="function"><a href="function.hash-hmac-file.html" class="function" rel="rdfs-seeAlso">hash_hmac_file()</a> - Generate a keyed hash value using the HMAC method and the contents of a given file</span></li>
</ul>
</p>
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