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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"><title>Crypto++: idea.cpp Source File</title><link href="doxygen.css" rel="stylesheet" type="text/css"><link href="tabs.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.5.2 --><div class="tabs"> <ul> <li><a href="index.html"><span>Main Page</span></a></li> <li><a href="namespaces.html"><span>Namespaces</span></a></li> <li><a href="classes.html"><span>Classes</span></a></li> <li class="current"><a href="files.html"><span>Files</span></a></li> </ul></div><div class="tabs"> <ul> <li><a href="files.html"><span>File List</span></a></li> <li><a href="globals.html"><span>File Members</span></a></li> </ul></div><h1>idea.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// idea.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 "<a class="code" href="idea_8h.html">idea.h</a>"</span><a name="l00005"></a>00005 <span class="preprocessor">#include "misc.h"</span><a name="l00006"></a>00006 <a name="l00007"></a>00007 NAMESPACE_BEGIN(CryptoPP)<a name="l00008"></a>00008 <a name="l00009"></a>00009 static const <span class="keywordtype">int</span> IDEA_KEYLEN=(6*<a class="code" href="class_i_d_e_a.html" title="IDEA">IDEA</a>::ROUNDS+4); <span class="comment">// key schedule length in # of word16s</span><a name="l00010"></a>00010 <a name="l00011"></a>00011 <span class="preprocessor">#define low16(x) ((x)&0xffff) // compiler should be able to optimize this away if word is 16 bits</span><a name="l00012"></a>00012 <span class="preprocessor"></span><span class="preprocessor">#define high16(x) ((x)>>16)</span><a name="l00013"></a>00013 <span class="preprocessor"></span><a name="l00014"></a>00014 CRYPTOPP_COMPILE_ASSERT(<span class="keyword">sizeof</span>(<a class="code" href="class_i_d_e_a.html#3ec08f4e29ea15045274d857582b07ab">IDEA::Word</a>) >= 2);<a name="l00015"></a>00015 <a name="l00016"></a>00016 <span class="comment">// should use an inline function but macros are still faster in MSVC 4.0</span><a name="l00017"></a>00017 <span class="preprocessor">#define DirectMUL(a,b) \</span><a name="l00018"></a>00018 <span class="preprocessor">{ \</span><a name="l00019"></a>00019 <span class="preprocessor"> assert(b <= 0xffff); \</span><a name="l00020"></a>00020 <span class="preprocessor"> \</span><a name="l00021"></a>00021 <span class="preprocessor"> word32 p=(word32)low16(a)*b; \</span><a name="l00022"></a>00022 <span class="preprocessor"> \</span><a name="l00023"></a>00023 <span class="preprocessor"> if (p) \</span><a name="l00024"></a>00024 <span class="preprocessor"> { \</span><a name="l00025"></a>00025 <span class="preprocessor"> p = low16(p) - high16(p); \</span><a name="l00026"></a>00026 <span class="preprocessor"> a = (IDEA::Word)p - (IDEA::Word)high16(p); \</span><a name="l00027"></a>00027 <span class="preprocessor"> } \</span><a name="l00028"></a>00028 <span class="preprocessor"> else \</span><a name="l00029"></a>00029 <span class="preprocessor"> a = 1-a-b; \</span><a name="l00030"></a>00030 <span class="preprocessor">}</span><a name="l00031"></a>00031 <span class="preprocessor"></span><a name="l00032"></a>00032 <span class="preprocessor">#ifdef IDEA_LARGECACHE</span><a name="l00033"></a>00033 <span class="preprocessor"></span><span class="keywordtype">bool</span> IDEA::Base::tablesBuilt = <span class="keyword">false</span>;<a name="l00034"></a>00034 word16 IDEA::Base::log[0x10000];<a name="l00035"></a>00035 word16 IDEA::Base::antilog[0x10000];<a name="l00036"></a>00036 <a name="l00037"></a>00037 <span class="keywordtype">void</span> IDEA::Base::BuildLogTables()<a name="l00038"></a>00038 {<a name="l00039"></a>00039 <span class="keywordflow">if</span> (tablesBuilt)<a name="l00040"></a>00040 <span class="keywordflow">return</span>;<a name="l00041"></a>00041 <span class="keywordflow">else</span><a name="l00042"></a>00042 {<a name="l00043"></a>00043 tablesBuilt = <span class="keyword">true</span>;<a name="l00044"></a>00044 <a name="l00045"></a>00045 <a class="code" href="class_i_d_e_a.html#3ec08f4e29ea15045274d857582b07ab">IDEA::Word</a> x=1;<a name="l00046"></a>00046 word32 i;<a name="l00047"></a>00047 <a name="l00048"></a>00048 <span class="keywordflow">for</span> (i=0; i<0x10000; i++)<a name="l00049"></a>00049 {<a name="l00050"></a>00050 antilog[i] = (word16)x;<a name="l00051"></a>00051 DirectMUL(x, 3);<a name="l00052"></a>00052 }<a name="l00053"></a>00053 <a name="l00054"></a>00054 <span class="keywordflow">for</span> (i=0; i<0x10000; i++)<a name="l00055"></a>00055 log[antilog[i]] = (word16)i;<a name="l00056"></a>00056 }<a name="l00057"></a>00057 }<a name="l00058"></a>00058 <a name="l00059"></a>00059 <span class="keywordtype">void</span> IDEA::Base::LookupKeyLogs()<a name="l00060"></a>00060 {<a name="l00061"></a>00061 <a class="code" href="class_i_d_e_a.html#3ec08f4e29ea15045274d857582b07ab">IDEA::Word</a>* Z=key;<a name="l00062"></a>00062 <span class="keywordtype">int</span> r=ROUNDS;<a name="l00063"></a>00063 <span class="keywordflow">do</span><a name="l00064"></a>00064 {<a name="l00065"></a>00065 Z[0] = log[Z[0]];<a name="l00066"></a>00066 Z[3] = log[Z[3]];<a name="l00067"></a>00067 Z[4] = log[Z[4]];<a name="l00068"></a>00068 Z[5] = log[Z[5]];<a name="l00069"></a>00069 Z+=6;<a name="l00070"></a>00070 } <span class="keywordflow">while</span> (--r);<a name="l00071"></a>00071 Z[0] = log[Z[0]];<a name="l00072"></a>00072 Z[3] = log[Z[3]];<a name="l00073"></a>00073 }<a name="l00074"></a>00074 <a name="l00075"></a>00075 <span class="keyword">inline</span> <span class="keywordtype">void</span> IDEA::Base::LookupMUL(<a class="code" href="class_i_d_e_a.html#3ec08f4e29ea15045274d857582b07ab">IDEA::Word</a> &a, <a class="code" href="class_i_d_e_a.html#3ec08f4e29ea15045274d857582b07ab">IDEA::Word</a> b)<a name="l00076"></a>00076 {<a name="l00077"></a>00077 a = antilog[low16(log[low16(a)]+b)];<a name="l00078"></a>00078 }<a name="l00079"></a>00079 <span class="preprocessor">#endif // IDEA_LARGECACHE</span><a name="l00080"></a>00080 <span class="preprocessor"></span><a name="l00081"></a>00081 <span class="keywordtype">void</span> IDEA::Base::UncheckedSetKey(<span class="keyword">const</span> byte *userKey, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> length, <span class="keyword">const</span> <a class="code" href="class_name_value_pairs.html" title="interface for retrieving values given their names">NameValuePairs</a> &)<a name="l00082"></a>00082 {<a name="l00083"></a>00083 AssertValidKeyLength(length);<a name="l00084"></a>00084 <a name="l00085"></a>00085 <span class="preprocessor">#ifdef IDEA_LARGECACHE</span><a name="l00086"></a>00086 <span class="preprocessor"></span> BuildLogTables();<a name="l00087"></a>00087 <span class="preprocessor">#endif</span><a name="l00088"></a>00088 <span class="preprocessor"></span> <a name="l00089"></a>00089 EnKey(userKey);⌨️ 快捷键说明
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