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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++: twofish.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>twofish.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// twofish.cpp - modified by Wei Dai from Matthew Skala's twofish.c</span><a name="l00002"></a>00002 <span class="comment">// The original code and all modifications are in the public domain.</span><a name="l00003"></a>00003 <a name="l00004"></a>00004 <span class="preprocessor">#include "pch.h"</span><a name="l00005"></a>00005 <span class="preprocessor">#include "<a class="code" href="twofish_8h.html">twofish.h</a>"</span><a name="l00006"></a>00006 <span class="preprocessor">#include "misc.h"</span><a name="l00007"></a>00007 <a name="l00008"></a>00008 NAMESPACE_BEGIN(CryptoPP)<a name="l00009"></a>00009 <a name="l00010"></a>00010 <span class="comment">// compute (c * x^4) mod (x^4 + (a + 1/a) * x^3 + a * x^2 + (a + 1/a) * x + 1)</span><a name="l00011"></a>00011 <span class="comment">// over GF(256)</span><a name="l00012"></a>00012 static inline <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> Mod(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> c)<a name="l00013"></a>00013 {<a name="l00014"></a>00014 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> modulus = 0x14d;<a name="l00015"></a>00015 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> c2 = (c<<1) ^ ((c & 0x80) ? modulus : 0);<a name="l00016"></a>00016 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> c1 = c2 ^ (c>>1) ^ ((c & 1) ? (modulus>>1) : 0);<a name="l00017"></a>00017 <span class="keywordflow">return</span> c | (c1 << 8) | (c2 << 16) | (c1 << 24);<a name="l00018"></a>00018 }<a name="l00019"></a>00019 <a name="l00020"></a>00020 <span class="comment">// compute RS(12,8) code with the above polynomial as generator</span><a name="l00021"></a>00021 <span class="comment">// this is equivalent to multiplying by the RS matrix</span><a name="l00022"></a>00022 <span class="keyword">static</span> word32 ReedSolomon(word32 high, word32 low)<a name="l00023"></a>00023 {<a name="l00024"></a>00024 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i=0; i<8; i++)<a name="l00025"></a>00025 {<a name="l00026"></a>00026 high = Mod(high>>24) ^ (high<<8) ^ (low>>24);<a name="l00027"></a>00027 low <<= 8;<a name="l00028"></a>00028 }<a name="l00029"></a>00029 <span class="keywordflow">return</span> high;<a name="l00030"></a>00030 }<a name="l00031"></a>00031 <a name="l00032"></a>00032 <span class="keyword">inline</span> word32 Twofish::Base::h0(word32 x, <span class="keyword">const</span> word32 *key, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> kLen)<a name="l00033"></a>00033 {<a name="l00034"></a>00034 x = x | (x<<8) | (x<<16) | (x<<24);<a name="l00035"></a>00035 <span class="keywordflow">switch</span>(kLen)<a name="l00036"></a>00036 {<a name="l00037"></a>00037 <span class="preprocessor">#define Q(a, b, c, d, t) q[a][GETBYTE(t,0)] ^ (q[b][GETBYTE(t,1)] << 8) ^ (q[c][GETBYTE(t,2)] << 16) ^ (q[d][GETBYTE(t,3)] << 24)</span><a name="l00038"></a>00038 <span class="preprocessor"></span> <span class="keywordflow">case</span> 4: x = Q(1, 0, 0, 1, x) ^ key[6];<a name="l00039"></a>00039 <span class="keywordflow">case</span> 3: x = Q(1, 1, 0, 0, x) ^ key[4];<a name="l00040"></a>00040 <span class="keywordflow">case</span> 2: x = Q(0, 1, 0, 1, x) ^ key[2];<a name="l00041"></a>00041 x = Q(0, 0, 1, 1, x) ^ key[0];<a name="l00042"></a>00042 }<a name="l00043"></a>00043 <span class="keywordflow">return</span> x;<a name="l00044"></a>00044 }<a name="l00045"></a>00045 <a name="l00046"></a>00046 <span class="keyword">inline</span> word32 Twofish::Base::h(word32 x, <span class="keyword">const</span> word32 *key, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> kLen)<a name="l00047"></a>00047 {<a name="l00048"></a>00048 x = h0(x, key, kLen);<a name="l00049"></a>00049 <span class="keywordflow">return</span> mds[0][GETBYTE(x,0)] ^ mds[1][GETBYTE(x,1)] ^ mds[2][GETBYTE(x,2)] ^ mds[3][GETBYTE(x,3)];<a name="l00050"></a>00050 }<a name="l00051"></a>00051 <a name="l00052"></a>00052 <span class="keywordtype">void</span> Twofish::Base::UncheckedSetKey(<span class="keyword">const</span> byte *userKey, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> keylength, <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="l00053"></a>00053 {<a name="l00054"></a>00054 <a class="code" href="class_simple_keying_interface.html#719efcf12f0de461b951830b8131b36a">AssertValidKeyLength</a>(keylength);<a name="l00055"></a>00055 <a name="l00056"></a>00056 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> len = (keylength <= 16 ? 2 : (keylength <= 24 ? 3 : 4));<a name="l00057"></a>00057 <a class="code" href="class_sec_block.html" title="a block of memory allocated using A">SecBlock<word32></a> key(len*2);<a name="l00058"></a>00058 GetUserKey(<a class="code" href="cryptlib_8h.html#aeb92d42f5a6e27b8ba19f18d69d142bccd5b3585bd07d6bdae383aa8271b9d2">LITTLE_ENDIAN_ORDER</a>, key.begin(), len*2, userKey, keylength);<a name="l00059"></a>00059 <a name="l00060"></a>00060 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i;<a name="l00061"></a>00061 <span class="keywordflow">for</span> (i=0; i<40; i+=2)<a name="l00062"></a>00062 {<a name="l00063"></a>00063 word32 a = h(i, key, len);<a name="l00064"></a>00064 word32 b = rotlFixed(h(i+1, key+1, len), 8);<a name="l00065"></a>00065 m_k[i] = a+b;<a name="l00066"></a>00066 m_k[i+1] = rotlFixed(a+2*b, 9);<a name="l00067"></a>00067 }<a name="l00068"></a>00068 <a name="l00069"></a>00069 <a class="code" href="class_sec_block.html" title="a block of memory allocated using A">SecBlock<word32></a> svec(2*len);<a name="l00070"></a>00070 <span class="keywordflow">for</span> (i=0; i<len; i++)<a name="l00071"></a>00071 svec[2*(len-i-1)] = ReedSolomon(key[2*i+1], key[2*i]);<a name="l00072"></a>00072 <span class="keywordflow">for</span> (i=0; i<256; i++)<a name="l00073"></a>00073 {<a name="l00074"></a>00074 word32 t = h0(i, svec, len);<a name="l00075"></a>00075 m_s[0][i] = mds[0][GETBYTE(t, 0)];<a name="l00076"></a>00076 m_s[1][i] = mds[1][GETBYTE(t, 1)];<a name="l00077"></a>00077 m_s[2][i] = mds[2][GETBYTE(t, 2)];<a name="l00078"></a>00078 m_s[3][i] = mds[3][GETBYTE(t, 3)];<a name="l00079"></a>00079 }<a name="l00080"></a>00080 }<a name="l00081"></a>00081 <a name="l00082"></a>00082 <span class="preprocessor">#define G1(x) (m_s[0][GETBYTE(x,0)] ^ m_s[1][GETBYTE(x,1)] ^ m_s[2][GETBYTE(x,2)] ^ m_s[3][GETBYTE(x,3)])</span><a name="l00083"></a>00083 <span class="preprocessor"></span><span class="preprocessor">#define G2(x) (m_s[0][GETBYTE(x,3)] ^ m_s[1][GETBYTE(x,0)] ^ m_s[2][GETBYTE(x,1)] ^ m_s[3][GETBYTE(x,2)])</span><a name="l00084"></a>00084 <span class="preprocessor"></span><a name="l00085"></a>00085 <span class="preprocessor">#define ENCROUND(n, a, b, c, d) \</span><a name="l00086"></a>00086 <span class="preprocessor"> x = G1 (a); y = G2 (b); \</span><a name="l00087"></a>00087 <span class="preprocessor"> x += y; y += x + k[2 * (n) + 1]; \</span><a name="l00088"></a>00088 <span class="preprocessor"> (c) ^= x + k[2 * (n)]; \</span><a name="l00089"></a>00089 <span class="preprocessor"> (c) = rotrFixed(c, 1); \</span><a name="l00090"></a>00090 <span class="preprocessor"> (d) = rotlFixed(d, 1) ^ y</span><a name="l00091"></a>00091 <span class="preprocessor"></span><a name="l00092"></a>00092 <span class="preprocessor">#define ENCCYCLE(n) \</span><a name="l00093"></a>00093 <span class="preprocessor"> ENCROUND (2 * (n), a, b, c, d); \</span><a name="l00094"></a>00094 <span class="preprocessor"> ENCROUND (2 * (n) + 1, c, d, a, b)</span><a name="l00095"></a>00095 <span class="preprocessor"></span><a name="l00096"></a>00096 <span class="preprocessor">#define DECROUND(n, a, b, c, d) \</span><a name="l00097"></a>00097 <span class="preprocessor"> x = G1 (a); y = G2 (b); \</span><a name="l00098"></a>00098 <span class="preprocessor"> x += y; y += x; \</span><a name="l00099"></a>00099 <span class="preprocessor"> (d) ^= y + k[2 * (n) + 1]; \</span><a name="l00100"></a>00100 <span class="preprocessor"> (d) = rotrFixed(d, 1); \</span><a name="l00101"></a>00101 <span class="preprocessor"> (c) = rotlFixed(c, 1); \</span><a name="l00102"></a>00102 <span class="preprocessor"> (c) ^= (x + k[2 * (n)])</span><a name="l00103"></a>00103 <span class="preprocessor"></span><a name="l00104"></a>00104 <span class="preprocessor">#define DECCYCLE(n) \</span><a name="l00105"></a>00105 <span class="preprocessor"> DECROUND (2 * (n) + 1, c, d, a, b); \</span><a name="l00106"></a>00106 <span class="preprocessor"> DECROUND (2 * (n), a, b, c, d)</span><a name="l00107"></a>00107 <span class="preprocessor"></span><a name="l00108"></a>00108 <span class="keyword">typedef</span> <a class="code" href="struct_block_get_and_put.html">BlockGetAndPut<word32, LittleEndian></a> <a class="code" href="struct_block_get_and_put.html">Block</a>;<a name="l00109"></a>00109 <a name="l00110"></a>00110 <span class="keywordtype">void</span> Twofish::Enc::ProcessAndXorBlock(<span class="keyword">const</span> byte *inBlock, <span class="keyword">const</span> byte *xorBlock, byte *outBlock)<span class="keyword"> const</span><a name="l00111"></a>00111 <span class="keyword"></span>{<a name="l00112"></a>00112 word32 x, y, a, b, c, d;<a name="l00113"></a>00113 <a name="l00114"></a>00114 <a class="code" href="struct_block_get_and_put.html#07781cc0817613fe47e8070999cf4b95">Block::Get</a>(inBlock)(a)(b)(c)(d);<a name="l00115"></a>00115 <a name="l00116"></a>00116 a ^= m_k[0];<a name="l00117"></a>00117 b ^= m_k[1];<a name="l00118"></a>00118 c ^= m_k[2];<a name="l00119"></a>00119 d ^= m_k[3];<a name="l00120"></a>00120 <a name="l00121"></a>00121 <span class="keyword">const</span> word32 *k = m_k+8;<a name="l00122"></a>00122 ENCCYCLE (0);<a name="l00123"></a>00123 ENCCYCLE (1);<a name="l00124"></a>00124 ENCCYCLE (2);<a name="l00125"></a>00125 ENCCYCLE (3);<a name="l00126"></a>00126 ENCCYCLE (4);<a name="l00127"></a>00127 ENCCYCLE (5);<a name="l00128"></a>00128 ENCCYCLE (6);<a name="l00129"></a>00129 ENCCYCLE (7);<a name="l00130"></a>00130 <a name="l00131"></a>00131 c ^= m_k[4];<a name="l00132"></a>00132 d ^= m_k[5];<a name="l00133"></a>00133 a ^= m_k[6];<a name="l00134"></a>00134 b ^= m_k[7]; <a name="l00135"></a>00135 <a name="l00136"></a>00136 <a class="code" href="struct_block_get_and_put.html#63d96a17e8118407e02896d0b0f8d92d">Block::Put</a>(xorBlock, outBlock)(c)(d)(a)(b);<a name="l00137"></a>00137 }<a name="l00138"></a>00138 <a name="l00139"></a>00139 <span class="keywordtype">void</span> Twofish::Dec::ProcessAndXorBlock(<span class="keyword">const</span> byte *inBlock, <span class="keyword">const</span> byte *xorBlock, byte *outBlock)<span class="keyword"> const</span><a name="l00140"></a>00140 <span class="keyword"></span>{<a name="l00141"></a>00141 word32 x, y, a, b, c, d;<a name="l00142"></a>00142 <a name="l00143"></a>00143 <a class="code" href="struct_block_get_and_put.html#07781cc0817613fe47e8070999cf4b95">Block::Get</a>(inBlock)(c)(d)(a)(b);<a name="l00144"></a>00144 <a name="l00145"></a>00145 c ^= m_k[4];<a name="l00146"></a>00146 d ^= m_k[5];<a name="l00147"></a>00147 a ^= m_k[6];<a name="l00148"></a>00148 b ^= m_k[7];<a name="l00149"></a>00149 <a name="l00150"></a>00150 <span class="keyword">const</span> word32 *k = m_k+8;<a name="l00151"></a>00151 DECCYCLE (7);<a name="l00152"></a>00152 DECCYCLE (6);<a name="l00153"></a>00153 DECCYCLE (5);<a name="l00154"></a>00154 DECCYCLE (4);<a name="l00155"></a>00155 DECCYCLE (3);<a name="l00156"></a>00156 DECCYCLE (2);<a name="l00157"></a>00157 DECCYCLE (1);<a name="l00158"></a>00158 DECCYCLE (0);<a name="l00159"></a>00159 <a name="l00160"></a>00160 a ^= m_k[0];<a name="l00161"></a>00161 b ^= m_k[1];<a name="l00162"></a>00162 c ^= m_k[2];<a name="l00163"></a>00163 d ^= m_k[3];<a name="l00164"></a>00164 <a name="l00165"></a>00165 <a class="code" href="struct_block_get_and_put.html#63d96a17e8118407e02896d0b0f8d92d">Block::Put</a>(xorBlock, outBlock)(a)(b)(c)(d);<a name="l00166"></a>00166 }<a name="l00167"></a>00167 <a name="l00168"></a>00168 NAMESPACE_END</pre></div><hr size="1"><address style="text-align: right;"><small>Generated on Fri Jun 1 11:11:25 2007 for Crypto++ by <a href="http://www.doxygen.org/index.html"><img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.2 </small></address></body></html>⌨️ 快捷键说明
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