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<h1>hmac.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// hmac.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
<a name="l00005"></a>00005 <span class="preprocessor">#ifndef CRYPTOPP_IMPORTS</span>
<a name="l00006"></a>00006 <span class="preprocessor"></span>
<a name="l00007"></a>00007 <span class="preprocessor">#include "hmac.h"</span>
<a name="l00008"></a>00008
<a name="l00009"></a>00009 NAMESPACE_BEGIN(CryptoPP)
<a name="l00010"></a>00010
<a name="l00011"></a>00011 void <a class="code" href="class_h_m_a_c___base.html" title="_">HMAC_Base</a>::UncheckedSetKey(const byte *userKey, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> keylength, const <a class="code" href="class_name_value_pairs.html" title="interface for retrieving values given their names">NameValuePairs</a> &)
<a name="l00012"></a>00012 {
<a name="l00013"></a>00013 AssertValidKeyLength(keylength);
<a name="l00014"></a>00014
<a name="l00015"></a>00015 Restart();
<a name="l00016"></a>00016
<a name="l00017"></a>00017 <a class="code" href="class_hash_transformation.html" title="interface for hash functions and data processing part of MACs">HashTransformation</a> &hash = AccessHash();
<a name="l00018"></a>00018 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> blockSize = hash.<a class="code" href="class_hash_transformation.html#ab5507c62376f6bea41d53ae9544d0ff0" title="block size of underlying compression function, or 0 if not block based">BlockSize</a>();
<a name="l00019"></a>00019
<a name="l00020"></a>00020 <span class="keywordflow">if</span> (!blockSize)
<a name="l00021"></a>00021 <span class="keywordflow">throw</span> <a class="code" href="class_invalid_argument.html" title="exception thrown when an invalid argument is detected">InvalidArgument</a>(<span class="stringliteral">"HMAC: can only be used with a block-based hash function"</span>);
<a name="l00022"></a>00022
<a name="l00023"></a>00023 m_buf.resize(2*AccessHash().BlockSize() + AccessHash().DigestSize());
<a name="l00024"></a>00024
<a name="l00025"></a>00025 <span class="keywordflow">if</span> (keylength <= blockSize)
<a name="l00026"></a>00026 memcpy(AccessIpad(), userKey, keylength);
<a name="l00027"></a>00027 <span class="keywordflow">else</span>
<a name="l00028"></a>00028 {
<a name="l00029"></a>00029 AccessHash().CalculateDigest(AccessIpad(), userKey, keylength);
<a name="l00030"></a>00030 keylength = hash.<a class="code" href="class_hash_transformation.html#a9f42cc280bac76b884ad12615c0dabb5" title="size of the hash/digest/MAC returned by Final()">DigestSize</a>();
<a name="l00031"></a>00031 }
<a name="l00032"></a>00032
<a name="l00033"></a>00033 assert(keylength <= blockSize);
<a name="l00034"></a>00034 memset(AccessIpad()+keylength, 0, blockSize-keylength);
<a name="l00035"></a>00035
<a name="l00036"></a>00036 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i=0; i<blockSize; i++)
<a name="l00037"></a>00037 {
<a name="l00038"></a>00038 AccessOpad()[i] = AccessIpad()[i] ^ 0x5c;
<a name="l00039"></a>00039 AccessIpad()[i] ^= 0x36;
<a name="l00040"></a>00040 }
<a name="l00041"></a>00041 }
<a name="l00042"></a>00042
<a name="l00043"></a>00043 <span class="keywordtype">void</span> HMAC_Base::KeyInnerHash()
<a name="l00044"></a>00044 {
<a name="l00045"></a>00045 assert(!m_innerHashKeyed);
<a name="l00046"></a>00046 <a class="code" href="class_hash_transformation.html" title="interface for hash functions and data processing part of MACs">HashTransformation</a> &hash = AccessHash();
<a name="l00047"></a>00047 hash.<a class="code" href="class_hash_transformation.html#aafabefaf445b65d3ba0d8e1c0294afe5" title="process more input">Update</a>(AccessIpad(), hash.<a class="code" href="class_hash_transformation.html#ab5507c62376f6bea41d53ae9544d0ff0" title="block size of underlying compression function, or 0 if not block based">BlockSize</a>());
<a name="l00048"></a>00048 m_innerHashKeyed = <span class="keyword">true</span>;
<a name="l00049"></a>00049 }
<a name="l00050"></a>00050
<a name="l00051"></a><a class="code" href="class_h_m_a_c___base.html#a7bdeb5438c920045d122017a6b4ab426">00051</a> <span class="keywordtype">void</span> <a class="code" href="class_h_m_a_c___base.html#a7bdeb5438c920045d122017a6b4ab426" title="discard the current state, and restart with a new message">HMAC_Base::Restart</a>()
<a name="l00052"></a>00052 {
<a name="l00053"></a>00053 <span class="keywordflow">if</span> (m_innerHashKeyed)
<a name="l00054"></a>00054 {
<a name="l00055"></a>00055 AccessHash().<a class="code" href="class_hash_transformation.html#a92752eebac10497211d7a065faba8725" title="discard the current state, and restart with a new message">Restart</a>();
<a name="l00056"></a>00056 m_innerHashKeyed = <span class="keyword">false</span>;
<a name="l00057"></a>00057 }
<a name="l00058"></a>00058 }
<a name="l00059"></a>00059
<a name="l00060"></a><a class="code" href="class_h_m_a_c___base.html#aefb8a1fb43ef8c9390ee89bbb41c83af">00060</a> <span class="keywordtype">void</span> <a class="code" href="class_h_m_a_c___base.html#aefb8a1fb43ef8c9390ee89bbb41c83af" title="process more input">HMAC_Base::Update</a>(<span class="keyword">const</span> byte *input, <span class="keywordtype">size_t</span> length)
<a name="l00061"></a>00061 {
<a name="l00062"></a>00062 <span class="keywordflow">if</span> (!m_innerHashKeyed)
<a name="l00063"></a>00063 KeyInnerHash();
<a name="l00064"></a>00064 AccessHash().<a class="code" href="class_hash_transformation.html#aafabefaf445b65d3ba0d8e1c0294afe5" title="process more input">Update</a>(input, length);
<a name="l00065"></a>00065 }
<a name="l00066"></a>00066
<a name="l00067"></a><a class="code" href="class_h_m_a_c___base.html#a5454c1446981ddee322b0521c6ebd375">00067</a> <span class="keywordtype">void</span> <a class="code" href="class_h_m_a_c___base.html#a5454c1446981ddee322b0521c6ebd375" title="truncated version of Final()">HMAC_Base::TruncatedFinal</a>(byte *mac, <span class="keywordtype">size_t</span> size)
<a name="l00068"></a>00068 {
<a name="l00069"></a>00069 ThrowIfInvalidTruncatedSize(size);
<a name="l00070"></a>00070
<a name="l00071"></a>00071 <a class="code" href="class_hash_transformation.html" title="interface for hash functions and data processing part of MACs">HashTransformation</a> &hash = AccessHash();
<a name="l00072"></a>00072
<a name="l00073"></a>00073 <span class="keywordflow">if</span> (!m_innerHashKeyed)
<a name="l00074"></a>00074 KeyInnerHash();
<a name="l00075"></a>00075 hash.<a class="code" href="class_hash_transformation.html#aa0b8c7a110d8968268fd02ec32b9a8e8" title="compute hash for current message, then restart for a new message">Final</a>(AccessInnerHash());
<a name="l00076"></a>00076
<a name="l00077"></a>00077 hash.<a class="code" href="class_hash_transformation.html#aafabefaf445b65d3ba0d8e1c0294afe5" title="process more input">Update</a>(AccessOpad(), hash.<a class="code" href="class_hash_transformation.html#ab5507c62376f6bea41d53ae9544d0ff0" title="block size of underlying compression function, or 0 if not block based">BlockSize</a>());
<a name="l00078"></a>00078 hash.<a class="code" href="class_hash_transformation.html#aafabefaf445b65d3ba0d8e1c0294afe5" title="process more input">Update</a>(AccessInnerHash(), hash.<a class="code" href="class_hash_transformation.html#a9f42cc280bac76b884ad12615c0dabb5" title="size of the hash/digest/MAC returned by Final()">DigestSize</a>());
<a name="l00079"></a>00079 hash.<a class="code" href="class_hash_transformation.html#a590ecda344aa0fb045abf42ec08823b2" title="truncated version of Final()">TruncatedFinal</a>(mac, size);
<a name="l00080"></a>00080
<a name="l00081"></a>00081 m_innerHashKeyed = <span class="keyword">false</span>;
<a name="l00082"></a>00082 }
<a name="l00083"></a>00083
<a name="l00084"></a>00084 NAMESPACE_END
<a name="l00085"></a>00085
<a name="l00086"></a>00086 <span class="preprocessor">#endif</span>
</pre></div></div>
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