openssl-open.xml

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<refentry xml:id="function.openssl-open" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>openssl_open</refname>
  <refpurpose>Open sealed data</refpurpose>
 </refnamediv>
 
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>openssl_open</methodname>
   <methodparam><type>string</type><parameter>data</parameter></methodparam>
   <methodparam><modifier role="attribute">#[\SensitiveParameter]</modifier><type>string</type><parameter role="reference">output</parameter></methodparam>
   <methodparam><type>string</type><parameter>encrypted_key</parameter></methodparam>
   <methodparam><modifier role="attribute">#[\SensitiveParameter]</modifier><type class="union"><type>OpenSSLAsymmetricKey</type><type>OpenSSLCertificate</type><type>array</type><type>string</type></type><parameter>private_key</parameter></methodparam>
   <methodparam><type>string</type><parameter>cipher_algo</parameter></methodparam>
   <methodparam choice="opt"><type class="union"><type>string</type><type>null</type></type><parameter>iv</parameter><initializer>&null;</initializer></methodparam>
  </methodsynopsis>
  <para>
   <function>openssl_open</function> opens (decrypts) <parameter>data</parameter> using an envelope
   key that is decrypted from <parameter>encrypted_key</parameter> using
   <parameter>private_key</parameter>. The decryption is done using
   <parameter>cipher_algo</parameter> and <parameter>iv</parameter>. The IV is required only if the
   cipher method requires it. The function fills <parameter>output</parameter> with the decrypted
   data. The envelope key is usually generated when the data are sealed using a public key that is
   associated with the private key. See <function>openssl_seal</function> for more information.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>data</parameter></term>
     <listitem>
      <para>
       The sealed data.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>output</parameter></term>
     <listitem>
      <para>
       If the call is successful the opened data is returned in this parameter.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>encrypted_key</parameter></term>
     <listitem>
      <para>
       The encrypted symmetric key that can be decrypted using <parameter>private_key</parameter>.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>private_key</parameter></term>
     <listitem>
      <para>
       The private key used for decrypting <parameter>encrypted_key</parameter>.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>cipher_algo</parameter></term>
     <listitem>
      <para>
       The cipher method used for decryption of <parameter>data</parameter>.
       <caution>
        <simpara>
         The default value for PHP versions prior to 8.0 is (<literal>'RC4'</literal>) which is
         considered insecure. It is strongly recommended to explicitly specify a secure cipher
         method.
        </simpara>
       </caution>
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>iv</parameter></term>
     <listitem>
      <para>
       The initialization vector used for decryption of <parameter>data</parameter>. It is required
       if the cipher method requires IV. This can be found out by calling
       <function>openssl_cipher_iv_length</function> with <parameter>cipher_algo</parameter>.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   &return.success;
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>8.0.0</entry>
      <entry>
       <parameter>private_key</parameter> accepts an <classname>OpenSSLAsymmetricKey</classname>
       or <classname>OpenSSLCertificate</classname> instance now;
       previously, a &resource; of type <literal>OpenSSL key</literal> or <literal>OpenSSL X.509 CSR</literal>
       was accepted.
      </entry>
     </row>
     <row>
      <entry>8.0.0</entry>
      <entry>
       <parameter>cipher_algo</parameter> is no longer an optional parameter.
      </entry>
     </row>
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>openssl_open</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php

// $sealed, $env_key and $iv are assumed to contain the sealed data, our
// envelope key and IV. All given to us by the sealer.

// Fetch private key from file located in private_key.pem
$pkey = openssl_get_privatekey("file://private_key.pem");

// Decrypt the data and store it in $open
if (openssl_open($sealed, $open, $env_key, $pkey, 'AES256', $iv)) {
    echo "Here is the opened data: ", $open;
} else {
    echo "Failed to open data";
}

?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>openssl_seal</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>
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