openssl-encrypt.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="function.openssl-encrypt" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>openssl_encrypt</refname>
  <refpurpose>加密数据</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type class="union"><type>string</type><type>false</type></type><methodname>openssl_encrypt</methodname>
   <methodparam><modifier role="attribute">#[\SensitiveParameter]</modifier><type>string</type><parameter>data</parameter></methodparam>
   <methodparam><type>string</type><parameter>cipher_algo</parameter></methodparam>
   <methodparam><modifier role="attribute">#[\SensitiveParameter]</modifier><type>string</type><parameter>passphrase</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>options</parameter><initializer>0</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>iv</parameter><initializer>""</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter role="reference">tag</parameter><initializer>&null;</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>aad</parameter><initializer>""</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>tag_length</parameter><initializer>16</initializer></methodparam>
  </methodsynopsis>
  <para>
   以指定的方式和 key 加密数据，返回原始或 base64 编码后的字符串。
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>data</parameter></term>
     <listitem>
      <para>
       待加密的明文信息数据。
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>cipher_algo</parameter></term>
     <listitem>
      <para>
       密码学方式。<function>openssl_get_cipher_methods</function> 可获取有效密码方式列表。
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>passphrase</parameter></term>
     <listitem>
      <para>
       口令（passphrase）。
       若 passphrase 比预期长度短，将静默用 <literal>NUL</literal> 填充；
       若比预期长度更长，将静默截断。
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
      <term><parameter>options</parameter></term>
      <listitem>
        <para>
          <parameter>options</parameter> 是以下标记的按位或：
         <constant>OPENSSL_RAW_DATA</constant> 和
         <constant>OPENSSL_ZERO_PADDING</constant>
         或 <constant>OPENSSL_DONT_ZERO_PAD_KEY</constant>。
        </para>
      </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>iv</parameter></term>
     <listitem>
      <para>
       非 NULL 的初始化向量。
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>tag</parameter></term>
     <listitem>
      <para>
       使用 AEAD 密码模式（GCM 或 CCM）时传引用的验证标签。
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>aad</parameter></term>
     <listitem>
      <para>
       附加的验证数据。
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>tag_length</parameter></term>
     <listitem>
      <para>
       验证 <parameter>tag</parameter> 的长度。GCM 模式时，它的范围是 4 到 16。
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   成功时返回加密后的字符串，&return.falseforfailure;。
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  <para>
   <parameter>cipher_algo</parameter> 传入未知算法时，产生 <constant>E_WARNING</constant> 级别的错误。
  </para>
  <para>
   <parameter>iv</parameter> 传入空字符串时产生 <constant>E_WARNING</constant> 级别的错误。
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>7.1.0</entry>
      <entry>增加了 <parameter>tag</parameter>、<parameter>aad</parameter>、<parameter>tag_length</parameter> 参数</entry>
     </row>
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>


 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>PHP 7.1 之前的 GCM 模式的 AES 认证加密示例</title>
    <programlisting role="php">
<![CDATA[
<?php
//$key should have been previously generated in a cryptographically safe way, like openssl_random_pseudo_bytes
$plaintext = "message to be encrypted";
$cipher = "aes-128-gcm";
if (in_array($cipher, openssl_get_cipher_methods()))
{
    $ivlen = openssl_cipher_iv_length($cipher);
    $iv = openssl_random_pseudo_bytes($ivlen);
    $ciphertext = openssl_encrypt($plaintext, $cipher, $key, $options=0, $iv, $tag);
    //store $cipher, $iv, and $tag for decryption later
    $original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
    echo $original_plaintext."\n";
}
?>
]]>
    </programlisting>
   </example>

   <example>
    <title>PHP 5.6+ 的 AES 认证加密例子</title>
    <programlisting role="php">
<![CDATA[
<?php
//$key previously generated safely, ie: openssl_random_pseudo_bytes
$plaintext = "message to be encrypted";
$ivlen = openssl_cipher_iv_length($cipher="AES-128-CBC");
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext_raw = openssl_encrypt($plaintext, $cipher, $key, $options=OPENSSL_RAW_DATA, $iv);
$hmac = hash_hmac('sha256', $ciphertext_raw, $key, $as_binary=true);
$ciphertext = base64_encode( $iv.$hmac.$ciphertext_raw );

//decrypt later....
$c = base64_decode($ciphertext);
$ivlen = openssl_cipher_iv_length($cipher="AES-128-CBC");
$iv = substr($c, 0, $ivlen);
$hmac = substr($c, $ivlen, $sha2len=32);
$ciphertext_raw = substr($c, $ivlen+$sha2len);
$original_plaintext = openssl_decrypt($ciphertext_raw, $cipher, $key, $options=OPENSSL_RAW_DATA, $iv);
$calcmac = hash_hmac('sha256', $ciphertext_raw, $key, $as_binary=true);
if (hash_equals($hmac, $calcmac))// timing attack safe comparison
{
    echo $original_plaintext."\n";
}
?>
]]>
    </programlisting>
   </example>

  </para>
 </refsect1>


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

</refentry>
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