php-doc-en/reference/mcrypt/functions/mcrypt-get-iv-size.xml
Philip Olson 305f655cf5 New doc style cleanup, markup changes only...
Example: <title>Description</title> to &reftitle.description;


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@259997 c90b9560-bf6c-de11-be94-00142212c4b1
2008-05-19 16:02:48 +00:00

84 lines
2.6 KiB
XML

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.12 $ -->
<refentry xml:id="function.mcrypt-get-iv-size" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>mcrypt_get_iv_size</refname>
<refpurpose>Returns the size of the IV belonging to a specific cipher/mode combination</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>int</type><methodname>mcrypt_get_iv_size</methodname>
<methodparam><type>string</type><parameter>cipher</parameter></methodparam>
<methodparam><type>string</type><parameter>mode</parameter></methodparam>
</methodsynopsis>
<para>
<function>mcrypt_get_iv_size</function> returns the size of
the Initialisation Vector (IV) in bytes. On error the function
returns &false;. If the IV is ignored in the specified cipher/mode
combination zero is returned.
</para>
<para>
<parameter>cipher</parameter> is one of the MCRYPT_ciphername
constants of the name of the algorithm as string.
</para>
<para>
<parameter>mode</parameter> is one of the MCRYPT_MODE_modename constants
or one of "ecb", "cbc", "cfb", "ofb", "nofb" or "stream". The IV is
ignored in ECB mode as this mode does not require it. You will need to
have the same IV (think: starting point) both at encryption and
decryption stages, otherwise your encryption will fail.
</para>
<para>
It is more useful to use the <function>mcrypt_enc_get_iv_size</function>
function as this uses the resource returned by
<function>mcrypt_module_open</function>.
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title><function>mcrypt_get_iv_size</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
echo mcrypt_get_iv_size(MCRYPT_CAST_256, MCRYPT_MODE_CFB) . "\n";
echo mcrypt_get_iv_size('des', 'ecb') . "\n";
?>
]]>
</programlisting>
</example>
</para>
<para>
See also
<function>mcrypt_get_block_size</function>,
<function>mcrypt_enc_get_iv_size</function> and
<function>mcrypt_create_iv</function>.
</para>
</refsect1>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"../../../../manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->