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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"><title>Crypto++: idea.cpp Source File</title><link href="doxygen.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.3.2 --><div class="qindex"><a class="qindex" href="index.html">Main Page</a> | <a class="qindex" href="namespaces.html">Namespace List</a> | <a class="qindex" href="hierarchy.html">Class Hierarchy</a> | <a class="qindex" href="classes.html">Alphabetical List</a> | <a class="qindex" href="annotated.html">Compound List</a> | <a class="qindex" href="files.html">File List</a> | <a class="qindex" href="namespacemembers.html">Namespace Members</a> | <a class="qindex" href="functions.html">Compound Members</a> | <a class="qindex" href="globals.html">File Members</a></div><h1>idea.cpp</h1><div class="fragment"><pre>00001 <span class="comment">// idea.cpp - written and placed in the public domain by Wei Dai</span>00002 00003 <span class="preprocessor">#include "pch.h"</span>00004 <span class="preprocessor">#include "<a class="code" href="idea_8h.html">idea.h</a>"</span>00005 <span class="preprocessor">#include "misc.h"</span>00006 00007 NAMESPACE_BEGIN(CryptoPP)00008 00009 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">int</span> IDEA_KEYLEN=(6*IDEA::ROUNDS+4); <span class="comment">// key schedule length in # of word16s</span>00010 00011 <span class="preprocessor">#define low16(x) ((x)&0xffff) // compiler should be able to optimize this away if word is 16 bits</span>00012 <span class="preprocessor"></span><span class="preprocessor">#define high16(x) ((x)>>16)</span>00013 <span class="preprocessor"></span>00014 <span class="comment">// should use an inline function but macros are still faster in MSVC 4.0</span>00015 <span class="preprocessor">#define DirectMUL(a,b) \</span>00016 <span class="preprocessor">{ \</span>00017 <span class="preprocessor"> assert(b <= 0xffff); \</span>00018 <span class="preprocessor"> \</span>00019 <span class="preprocessor"> word32 p=(word32)low16(a)*b; \</span>00020 <span class="preprocessor"> \</span>00021 <span class="preprocessor"> if (p) \</span>00022 <span class="preprocessor"> { \</span>00023 <span class="preprocessor"> p = low16(p) - high16(p); \</span>00024 <span class="preprocessor"> a = (word)p - (word)high16(p); \</span>00025 <span class="preprocessor"> } \</span>00026 <span class="preprocessor"> else \</span>00027 <span class="preprocessor"> a = 1-a-b; \</span>00028 <span class="preprocessor">}</span>00029 <span class="preprocessor"></span>00030 <span class="preprocessor">#ifdef IDEA_LARGECACHE</span>00031 <span class="preprocessor"></span><span class="keywordtype">bool</span> IDEA::Base::tablesBuilt = <span class="keyword">false</span>;00032 word16 IDEA::Base::log[0x10000];00033 word16 IDEA::Base::antilog[0x10000];00034 00035 <span class="keywordtype">void</span> IDEA::Base::BuildLogTables()00036 {00037 <span class="keywordflow">if</span> (tablesBuilt)00038 <span class="keywordflow">return</span>;00039 <span class="keywordflow">else</span>00040 {00041 tablesBuilt = <span class="keyword">true</span>;00042 00043 word x=1;00044 word32 i;00045 00046 <span class="keywordflow">for</span> (i=0; i<0x10000; i++)00047 {00048 antilog[i] = (word16)x;00049 DirectMUL(x, 3);00050 }00051 00052 <span class="keywordflow">for</span> (i=0; i<0x10000; i++)00053 log[antilog[i]] = (word16)i;00054 }00055 }00056 00057 <span class="keywordtype">void</span> IDEA::Base::LookupKeyLogs()00058 {00059 word* Z=key;00060 <span class="keywordtype">int</span> r=ROUNDS;00061 <span class="keywordflow">do</span>00062 {00063 Z[0] = log[Z[0]];00064 Z[3] = log[Z[3]];00065 Z[4] = log[Z[4]];00066 Z[5] = log[Z[5]];00067 Z+=6;00068 } <span class="keywordflow">while</span> (--r);00069 Z[0] = log[Z[0]];00070 Z[3] = log[Z[3]];00071 }00072 00073 <span class="keyword">inline</span> <span class="keywordtype">void</span> IDEA::Base::LookupMUL(word &a, word b)00074 {00075 a = antilog[low16(log[low16(a)]+b)];00076 }00077 <span class="preprocessor">#endif // IDEA_LARGECACHE</span>00078 <span class="preprocessor"></span>00079 <span class="keywordtype">void</span> IDEA::Base::UncheckedSetKey(CipherDir direction, <span class="keyword">const</span> byte *userKey, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> length)00080 {00081 AssertValidKeyLength(length);00082 00083 <span class="preprocessor">#ifdef IDEA_LARGECACHE</span>00084 <span class="preprocessor"></span> BuildLogTables();00085 <span class="preprocessor">#endif</span>00086 <span class="preprocessor"></span> 00087 EnKey(userKey);00088 00089 <span class="keywordflow">if</span> (direction==DECRYPTION)00090 DeKey();00091 00092 <span class="preprocessor">#ifdef IDEA_LARGECACHE</span>00093 <span class="preprocessor"></span> LookupKeyLogs();00094 <span class="preprocessor">#endif</span>00095 <span class="preprocessor"></span>}00096 00097 <span class="keywordtype">void</span> IDEA::Base::EnKey (<span class="keyword">const</span> byte *userKey)00098 {00099 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i;00100 00101 <span class="keywordflow">for</span> (i=0; i<8; i++)00102 m_key[i] = ((word)userKey[2*i]<<8) | userKey[2*i+1];00103 00104 <span class="keywordflow">for</span> (; i<IDEA_KEYLEN; i++)00105 {00106 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> j = RoundDownToMultipleOf(i,8U)-8;00107 m_key[i] = low16((m_key[j+(i+1)%8] << 9) | (m_key[j+(i+2)%8] >> 7));00108 }00109 }00110 00111 <span class="keyword">static</span> word MulInv(word x)00112 {00113 word y=x;00114 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> i=0; i<15; i++)00115 {00116 DirectMUL(y,low16(y));00117 DirectMUL(y,x);00118 }00119 <span class="keywordflow">return</span> low16(y);00120 }00121 00122 <span class="keyword">static</span> <span class="keyword">inline</span> word AddInv(word x)00123 {00124 <span class="keywordflow">return</span> low16(0-x);00125 }00126 00127 <span class="keywordtype">void</span> IDEA::Base::DeKey()00128 {00129 FixedSizeSecBlock<word, 6*ROUNDS+4> tempkey;00130 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i;00131 00132 <span class="keywordflow">for</span> (i=0; i<ROUNDS; i++)00133 {00134 tempkey[i*6+0] = MulInv(m_key[(ROUNDS-i)*6+0]);00135 tempkey[i*6+1] = AddInv(m_key[(ROUNDS-i)*6+1+(i>0)]);00136 tempkey[i*6+2] = AddInv(m_key[(ROUNDS-i)*6+2-(i>0)]);00137 tempkey[i*6+3] = MulInv(m_key[(ROUNDS-i)*6+3]);00138 tempkey[i*6+4] = m_key[(ROUNDS-1-i)*6+4];00139 tempkey[i*6+5] = m_key[(ROUNDS-1-i)*6+5];00140 }00141 00142 tempkey[i*6+0] = MulInv(m_key[(ROUNDS-i)*6+0]);00143 tempkey[i*6+1] = AddInv(m_key[(ROUNDS-i)*6+1]);00144 tempkey[i*6+2] = AddInv(m_key[(ROUNDS-i)*6+2]);00145 tempkey[i*6+3] = MulInv(m_key[(ROUNDS-i)*6+3]);00146 00147 m_key = tempkey;00148 }00149 00150 <span class="preprocessor">#ifdef IDEA_LARGECACHE</span>00151 <span class="preprocessor"></span><span class="preprocessor">#define MUL(a,b) LookupMUL(a,b)</span>00152 <span class="preprocessor"></span><span class="preprocessor">#else</span>00153 <span class="preprocessor"></span><span class="preprocessor">#define MUL(a,b) DirectMUL(a,b)</span>00154 <span class="preprocessor"></span><span class="preprocessor">#endif</span>00155 <span class="preprocessor"></span>00156 <span class="keywordtype">void</span> IDEA::Base::ProcessAndXorBlock(<span class="keyword">const</span> byte *inBlock, <span class="keyword">const</span> byte *xorBlock, byte *outBlock)<span class="keyword"> const</span>00157 <span class="keyword"></span>{00158 <span class="keyword">typedef</span> BlockGetAndPut<word16, BigEndian> Block;00159 00160 <span class="keyword">const</span> word *key = m_key;00161 word x0,x1,x2,x3,t0,t1;00162 Block::Get(inBlock)(x0)(x1)(x2)(x3);00163 00164 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i=0; i<ROUNDS; i++)00165 {00166 MUL(x0, key[i*6+0]);00167 x1 += key[i*6+1];00168 x2 += key[i*6+2];00169 MUL(x3, key[i*6+3]);00170 t0 = x0^x2; 00171 MUL(t0, key[i*6+4]);00172 t1 = t0 + (x1^x3);00173 MUL(t1, key[i*6+5]);00174 t0 += t1;00175 x0 ^= t1;00176 x3 ^= t0;00177 t0 ^= x1;00178 x1 = x2^t1;00179 x2 = t0;00180 }00181 00182 MUL(x0, key[ROUNDS*6+0]);00183 x2 += key[ROUNDS*6+1];00184 x1 += key[ROUNDS*6+2];00185 MUL(x3, key[ROUNDS*6+3]);00186 00187 Block::Put(xorBlock, outBlock)(x0)(x2)(x1)(x3);00188 }00189 00190 NAMESPACE_END</pre></div><hr size="1"><address style="align: right;"><small>Generated on Tue Jul 8 23:34:16 2003 for Crypto++ by<a href="http://www.doxygen.org/index.html"><img src="doxygen.png" alt="doxygen" align="middle" border=0 > </a>1.3.2 </small></address></body></html>⌨️ 快捷键说明
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