1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>In-place Cipher operation</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Linux Kernel Crypto API"><link rel="up" href="User.html" title="Chapter&#160;4.&#160;User Space Interface"><link rel="prev" href="ch04s02.html" title="User Space API General Remarks"><link rel="next" href="ch04s04.html" title="Message Digest API"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">In-place Cipher operation</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch04s02.html">Prev</a>&#160;</td><th width="60%" align="center">Chapter&#160;4.&#160;User Space Interface</th><td width="20%" align="right">&#160;<a accesskey="n" href="ch04s04.html">Next</a></td></tr></table><hr></div><div class="sect1"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1097355020"></a>In-place Cipher operation</h2></div></div></div><p>
2     Just like the in-kernel operation of the kernel crypto API, the user
3     space interface allows the cipher operation in-place. That means that
4     the input buffer used for the send/write system call and the output
5     buffer used by the read/recv system call may be one and the same.
6     This is of particular interest for symmetric cipher operations where a
7     copying of the output data to its final destination can be avoided.
8    </p><p>
9     If a consumer on the other hand wants to maintain the plaintext and
10     the ciphertext in different memory locations, all a consumer needs
11     to do is to provide different memory pointers for the encryption and
12     decryption operation.
13    </p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch04s02.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="User.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="ch04s04.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">User Space API General Remarks&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;Message Digest API</td></tr></table></div></body></html>
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