hash-hmac-file.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="function.hash-hmac-file" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>hash_hmac_file</refname>
  <refpurpose>Generate a keyed hash value using the HMAC method and the contents of a given file</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type class="union"><type>string</type><type>false</type></type><methodname>hash_hmac_file</methodname>
   <methodparam><type>string</type><parameter>algo</parameter></methodparam>
   <methodparam><type>string</type><parameter>filename</parameter></methodparam>
   <methodparam><modifier role="attribute">#[\SensitiveParameter]</modifier><type>string</type><parameter>key</parameter></methodparam>
   <methodparam choice="opt"><type>bool</type><parameter>binary</parameter><initializer>&false;</initializer></methodparam>
  </methodsynopsis>

 </refsect1>
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>algo</parameter></term>
     <listitem>
      <para>
       Name of selected hashing algorithm (e.g. <literal>"sha256"</literal>).
       For a list of supported algorithms see <function>hash_hmac_algos</function>.
       <note>
        <para>
         Non-cryptographic hash functions are not allowed.
        </para>
       </note>
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>filename</parameter></term>
     <listitem>
      <para>
       URL describing location of file to be hashed; Supports fopen wrappers.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>key</parameter></term>
     <listitem>
      <para>
       Shared secret key used for generating the HMAC variant of the message digest.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>binary</parameter></term>
     <listitem>
      <para>
       When set to &true;, outputs raw binary data.
       &false; outputs lowercase hexits.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns a string containing the calculated message digest as lowercase hexits
   unless <parameter>binary</parameter> is set to true in which case the raw
   binary representation of the message digest is returned.
   Returns &false; if the file <parameter>filename</parameter> cannot be read.
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  <para>
   Throws a <classname>ValueError</classname> exception if
   <parameter>algo</parameter> is unknown or is a non-cryptographic hash function.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>8.0.0</entry>
       <entry>
        Now throws a <classname>ValueError</classname> exception if
        <parameter>algo</parameter> is unknown or is a non-cryptographic hash
        function; previously, &false; was returned instead.
       </entry>
      </row>
      <row>
       <entry>7.2.0</entry>
       <entry>Usage of non-cryptographic hash functions (adler32, crc32, crc32b, fnv132, fnv1a32, fnv164, fnv1a64, joaat) was disabled.</entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>hash_hmac_file</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
/* Create a file to calculate hash of */
file_put_contents('example.txt', 'The quick brown fox jumped over the lazy dog.');

echo hash_hmac_file('sha256', 'example.txt', 'secret');
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
9c5c42422b03f0ee32949920649445e417b2c634050833c5165704b825c2a53b
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>hash_hmac</function></member>
    <member><function>hash_hmac_algos</function></member>
    <member><function>hash_init</function></member>
    <member><function>hash_equals</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>
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