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<div class="title">eax.cpp</div> </div>
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<div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// eax.cpp - written and placed in the public domain by Wei Dai</span>
<a name="l00002"></a>00002
<a name="l00003"></a>00003 <span class="preprocessor">#include "pch.h"</span>
<a name="l00004"></a>00004 <span class="preprocessor">#include "eax.h"</span>
<a name="l00005"></a>00005
<a name="l00006"></a>00006 NAMESPACE_BEGIN(CryptoPP)
<a name="l00007"></a>00007
<a name="l00008"></a>00008 void <a class="code" href="class_e_a_x___base.html" title=".">EAX_Base</a>::SetKeyWithoutResync(const byte *userKey, <span class="keywordtype">size_t</span> keylength, const <a class="code" href="class_name_value_pairs.html" title="interface for retrieving values given their names">NameValuePairs</a> &params)
<a name="l00009"></a>00009 {
<a name="l00010"></a>00010 AccessMAC().<a class="code" href="class_authenticated_symmetric_cipher_base.html#aea1353c1d0a94c3f81ebcf53f6b7ea57" title="set or reset the key of this object">SetKey</a>(userKey, keylength, params);
<a name="l00011"></a>00011 m_buffer.New(2*AccessMAC().TagSize());
<a name="l00012"></a>00012 }
<a name="l00013"></a>00013
<a name="l00014"></a>00014 <span class="keywordtype">void</span> EAX_Base::Resync(<span class="keyword">const</span> byte *iv, <span class="keywordtype">size_t</span> len)
<a name="l00015"></a>00015 {
<a name="l00016"></a>00016 <a class="code" href="class_message_authentication_code.html" title="interface for message authentication codes">MessageAuthenticationCode</a> &mac = AccessMAC();
<a name="l00017"></a>00017 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> blockSize = mac.<a class="code" href="class_hash_transformation.html#a5e847d65a38ec354de1b28cc4bc66a81" title="same as DigestSize()">TagSize</a>();
<a name="l00018"></a>00018
<a name="l00019"></a>00019 memset(m_buffer, 0, blockSize);
<a name="l00020"></a>00020 mac.<a class="code" href="class_hash_transformation.html#aafabefaf445b65d3ba0d8e1c0294afe5" title="process more input">Update</a>(m_buffer, blockSize);
<a name="l00021"></a>00021 mac.<a class="code" href="class_hash_transformation.html#af8124c4fca23b74bbdc43660bdae692c" title="use this if your input is in one piece and you don't want to call Update() and Final() separately...">CalculateDigest</a>(m_buffer+blockSize, iv, len);
<a name="l00022"></a>00022
<a name="l00023"></a>00023 m_buffer[blockSize-1] = 1;
<a name="l00024"></a>00024 mac.<a class="code" href="class_hash_transformation.html#aafabefaf445b65d3ba0d8e1c0294afe5" title="process more input">Update</a>(m_buffer, blockSize);
<a name="l00025"></a>00025
<a name="l00026"></a>00026 m_ctr.SetCipherWithIV(AccessMAC().AccessCipher(), m_buffer+blockSize, blockSize);
<a name="l00027"></a>00027 }
<a name="l00028"></a>00028
<a name="l00029"></a>00029 <span class="keywordtype">size_t</span> EAX_Base::AuthenticateBlocks(<span class="keyword">const</span> byte *data, <span class="keywordtype">size_t</span> len)
<a name="l00030"></a>00030 {
<a name="l00031"></a>00031 AccessMAC().<a class="code" href="class_c_m_a_c___base.html#a582cd6d32b41c65d10481ebcd2c1aed4" title="process more input">Update</a>(data, len);
<a name="l00032"></a>00032 <span class="keywordflow">return</span> 0;
<a name="l00033"></a>00033 }
<a name="l00034"></a>00034
<a name="l00035"></a>00035 <span class="keywordtype">void</span> EAX_Base::AuthenticateLastHeaderBlock()
<a name="l00036"></a>00036 {
<a name="l00037"></a>00037 assert(m_bufferedDataLength == 0);
<a name="l00038"></a>00038 <a class="code" href="class_message_authentication_code.html" title="interface for message authentication codes">MessageAuthenticationCode</a> &mac = AccessMAC();
<a name="l00039"></a>00039 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> blockSize = mac.<a class="code" href="class_hash_transformation.html#a5e847d65a38ec354de1b28cc4bc66a81" title="same as DigestSize()">TagSize</a>();
<a name="l00040"></a>00040
<a name="l00041"></a>00041 mac.<a class="code" href="class_hash_transformation.html#aa0b8c7a110d8968268fd02ec32b9a8e8" title="compute hash for current message, then restart for a new message">Final</a>(m_buffer);
<a name="l00042"></a>00042 xorbuf(m_buffer+blockSize, m_buffer, blockSize);
<a name="l00043"></a>00043
<a name="l00044"></a>00044 memset(m_buffer, 0, blockSize);
<a name="l00045"></a>00045 m_buffer[blockSize-1] = 2;
<a name="l00046"></a>00046 mac.<a class="code" href="class_hash_transformation.html#aafabefaf445b65d3ba0d8e1c0294afe5" title="process more input">Update</a>(m_buffer, blockSize);
<a name="l00047"></a>00047 }
<a name="l00048"></a>00048
<a name="l00049"></a>00049 <span class="keywordtype">void</span> EAX_Base::AuthenticateLastFooterBlock(byte *tag, <span class="keywordtype">size_t</span> macSize)
<a name="l00050"></a>00050 {
<a name="l00051"></a>00051 assert(m_bufferedDataLength == 0);
<a name="l00052"></a>00052 <a class="code" href="class_message_authentication_code.html" title="interface for message authentication codes">MessageAuthenticationCode</a> &mac = AccessMAC();
<a name="l00053"></a>00053 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> blockSize = mac.<a class="code" href="class_hash_transformation.html#a5e847d65a38ec354de1b28cc4bc66a81" title="same as DigestSize()">TagSize</a>();
<a name="l00054"></a>00054
<a name="l00055"></a>00055 mac.<a class="code" href="class_hash_transformation.html#a590ecda344aa0fb045abf42ec08823b2" title="truncated version of Final()">TruncatedFinal</a>(m_buffer, macSize);
<a name="l00056"></a>00056 xorbuf(tag, m_buffer, m_buffer+blockSize, macSize);
<a name="l00057"></a>00057 }
<a name="l00058"></a>00058
<a name="l00059"></a>00059 NAMESPACE_END
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