<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >mcrypt_enc_get_iv_size</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="Mcrypt Encryption Functions" HREF="ref.mcrypt.html"><LINK REL="PREVIOUS" TITLE="mcrypt_enc_get_block_size" HREF="function.mcrypt-enc-get-block-size.html"><LINK REL="NEXT" TITLE="mcrypt_enc_get_key_size" HREF="function.mcrypt-enc-get-key-size.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.mcrypt-enc-get-block-size.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.mcrypt-enc-get-key-size.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.mcrypt-enc-get-iv-size" ></A >mcrypt_enc_get_iv_size</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN115512" ></A ><P > (PHP 4 >= 4.0.2, PHP 5)</P >mcrypt_enc_get_iv_size -- Returns the size of the IV of the opened algorithm</DIV ><DIV CLASS="refsect1" ><A NAME="AEN115515" ></A ><H2 >Description</H2 >int <B CLASS="methodname" >mcrypt_enc_get_iv_size</B > ( resource td )<BR ></BR ><P > This function returns the size of the iv of the algorithm specified by the encryption descriptor in bytes. If it returns '0' then the IV is ignored in the algorithm. An IV is used in cbc, cfb and ofb modes, and in some algorithms in stream mode. </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.mcrypt-enc-get-block-size.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.mcrypt-enc-get-key-size.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >mcrypt_enc_get_block_size</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.mcrypt.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >mcrypt_enc_get_key_size</TD ></TR ></TABLE ></DIV ></BODY ></HTML >