1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>crypto_aead_authsize</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="ch05s05.html" title="Authenticated Encryption With Associated Data (AEAD) Cipher API"><link rel="prev" href="API-crypto-aead-ivsize.html" title="crypto_aead_ivsize"><link rel="next" href="API-crypto-aead-blocksize.html" title="crypto_aead_blocksize"></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"><span class="phrase">crypto_aead_authsize</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-crypto-aead-ivsize.html">Prev</a>&#160;</td><th width="60%" align="center">Authenticated Encryption With Associated Data (AEAD) Cipher API</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-crypto-aead-blocksize.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-crypto-aead-authsize"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>crypto_aead_authsize &#8212; 
2  obtain maximum authentication data size
3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">unsigned int <b class="fsfunc">crypto_aead_authsize </b>(</code></td><td>struct crypto_aead * <var class="pdparam">tfm</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1097652164"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>tfm</code></em></span></dt><dd><p>
4     cipher handle
5    </p></dd></dl></div></div><div class="refsect1"><a name="idp1097653692"></a><h2>Description</h2><p>
6   The maximum size of the authentication data for the AEAD cipher referenced
7   by the AEAD cipher handle is returned. The authentication data size may be
8   zero if the cipher implements a hard-coded maximum.
9   </p><p>
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11   The authentication data may also be known as <span class="quote">&#8220;<span class="quote">tag value</span>&#8221;</span>.
12</p></div><div class="refsect1"><a name="idp1097654868"></a><h2>Return</h2><p>
13   authentication data size / tag size in bytes
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