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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>Initialize an incremental hashing context</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.hash-hmac.html">hash_hmac</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.hash-update-file.html">hash_update_file</a></div> <div class="up"><a href="ref.hash.html">Hash Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.hash-init" class="refentry"> <div class="refnamediv">  <h1 class="refname">hash_init</h1>  <p class="verinfo">(PHP 5 &gt;= 5.1.2, PECL hash:1.1-1.5)</p><p class="refpurpose"><span class="refname">hash_init</span> &mdash; <span class="dc-title">Initialize an incremental hashing context</span></p> </div> <div class="refsect1 description">  <h3 class="title">Description</h3>  <div class="methodsynopsis dc-description">   <span class="type">resource</span> <span class="methodname"><b><b>hash_init</b></b></span>    ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$algo</tt></span>   [, <span class="methodparam"><span class="type">int</span> <tt class="parameter">$options</tt></span>   [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$key</tt></span>  ]] )</div> </div> <div class="refsect1 parameters">  <h3 class="title">Parameters</h3>  <p class="para">   <dl>    <dt>     <span class="term"><i><tt class="parameter">algo</tt></i></span>     <dd>      <p class="para">       Name of selected hashing algorithm (i.e. &quot;md5&quot;, &quot;sha256&quot;, &quot;haval160,4&quot;, etc..)      </p>     </dd>    </dt>    <dt>     <span class="term"><i><tt class="parameter">options</tt></i></span>     <dd>      <p class="para">       Optional settings for hash generation, currently supports only one option:       <b><tt>HASH_HMAC</tt></b>.  When specified, the <i><tt class="parameter">key</tt></i>       <em class="emphasis">must</em> be specified.      </p>     </dd>    </dt>    <dt>     <span class="term"><i><tt class="parameter">key</tt></i></span>     <dd>      <p class="para">       When <b><tt>HASH_HMAC</tt></b> is specified for <i><tt class="parameter">options</tt></i>,       a shared secret key to be used with the HMAC hashing method must be supplied in this       parameter.      </p>     </dd>    </dt>   </dl>  </p> </div> <div class="refsect1 returnvalues">  <h3 class="title">Return Values</h3>  <p class="para">   Returns a Hashing Context resource for use with <a href="function.hash-update.html" class="function">hash_update()</a>,   <a href="function.hash-update-stream.html" class="function">hash_update_stream()</a>, <a href="function.hash-update-file.html" class="function">hash_update_file()</a>,   and <a href="function.hash-final.html" class="function">hash_final()</a>.  </p> </div> <div class="refsect1 examples">  <h3 class="title">Examples</h3>  <p class="para">   <div class="example">    <p><b>Example #1 Incremental hashing example</b></p>    <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB">&lt;?php<br />$ctx&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">hash_init</span><span style="color: #007700">(</span><span style="color: #DD0000">'md5'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">hash_update</span><span style="color: #007700">(</span><span style="color: #0000BB">$ctx</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'The&nbsp;quick&nbsp;brown&nbsp;fox&nbsp;'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">hash_update</span><span style="color: #007700">(</span><span style="color: #0000BB">$ctx</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'jumped&nbsp;over&nbsp;the&nbsp;lazy&nbsp;dog.'</span><span style="color: #007700">);<br />echo&nbsp;</span><span style="color: #0000BB">hash_final</span><span style="color: #007700">(</span><span style="color: #0000BB">$ctx</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span></span></code></div>    </div>    <div class="example-contents"><p>The above example will output:</p></div>    <div class="example-contents"><pre><div class="cdata"><pre>5c6ffbdd40d9556b73a21e63c3e0e904</pre></div>    </pre></div>   </div>  </p> </div> <div class="refsect1 seealso">  <h3 class="title">See Also</h3>  <p class="para">   <ul class="simplelist">    <li class="member"><a href="function.hash.html" class="function" rel="rdfs-seeAlso">hash()</a></li>    <li class="member"><a href="function.hash-file.html" class="function" rel="rdfs-seeAlso">hash_file()</a></li>    <li class="member"><a href="function.hash-hmac.html" class="function" rel="rdfs-seeAlso">hash_hmac()</a></li>    <li class="member"><a href="function.hash-hmac-file.html" class="function" rel="rdfs-seeAlso">hash_hmac_file()</a></li>   </ul>  </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.hash-hmac.html">hash_hmac</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.hash-update-file.html">hash_update_file</a></div> <div class="up"><a href="ref.hash.html">Hash Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>
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