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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++: twofish.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>twofish.cpp</h1><div class="fragment"><pre>00001 <span class="comment">// twofish.cpp - modified by Wei Dai from Matthew Skala's twofish.c</span>00002 <span class="comment">// The original code and all modifications are in the public domain.</span>00003 00004 <span class="preprocessor">#include "pch.h"</span>00005 <span class="preprocessor">#include "<a class="code" href="twofish_8h.html">twofish.h</a>"</span>00006 <span class="preprocessor">#include "misc.h"</span>00007 00008 NAMESPACE_BEGIN(CryptoPP)00009 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>00011 <span class="comment">// over GF(256)</span>00012 <span class="keyword">static</span> <span class="keyword">inline</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> Mod(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> c)00013 {00014 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> modulus = 0x14d;00015 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> c2 = (c<<1) ^ ((c & 0x80) ? modulus : 0);00016 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> c1 = c2 ^ (c>>1) ^ ((c & 1) ? (modulus>>1) : 0);00017 <span class="keywordflow">return</span> c | (c1 << 8) | (c2 << 16) | (c1 << 24);00018 }00019 00020 <span class="comment">// compute RS(12,8) code with the above polynomial as generator</span>00021 <span class="comment">// this is equivalent to multiplying by the RS matrix</span>00022 <span class="keyword">static</span> word32 ReedSolomon(word32 high, word32 low)00023 {00024 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i=0; i<8; i++)00025 {00026 high = Mod(high>>24) ^ (high<<8) ^ (low>>24);00027 low <<= 8;00028 }00029 <span class="keywordflow">return</span> high;00030 }00031 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)00033 {00034 x = x | (x<<8) | (x<<16) | (x<<24);00035 <span class="keywordflow">switch</span>(kLen)00036 {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>00038 <span class="preprocessor"></span> <span class="keywordflow">case</span> 4: x = Q(1, 0, 0, 1, x) ^ key[6];00039 <span class="keywordflow">case</span> 3: x = Q(1, 1, 0, 0, x) ^ key[4];00040 <span class="keywordflow">case</span> 2: x = Q(0, 1, 0, 1, x) ^ key[2];00041 x = Q(0, 0, 1, 1, x) ^ key[0];00042 }00043 <span class="keywordflow">return</span> x;00044 }00045 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)00047 {00048 x = h0(x, key, kLen);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)];00050 }00051 00052 <span class="keywordtype">void</span> Twofish::Base::UncheckedSetKey(CipherDir dir, <span class="keyword">const</span> byte *userKey, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> keylength)00053 {00054 AssertValidKeyLength(keylength);00055 00056 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> len = (keylength <= 16 ? 2 : (keylength <= 24 ? 3 : 4));00057 <a class="code" href="class_sec_block.html">SecBlock<word32></a> key(len*2);00058 GetUserKey(LITTLE_ENDIAN_ORDER, key.<a class="code" href="class_sec_block.html#_sec_block_with_hinta7">begin</a>(), len*2, userKey, keylength);00059 00060 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i;00061 <span class="keywordflow">for</span> (i=0; i<40; i+=2)00062 {00063 word32 a = h(i, key, len);00064 word32 b = rotlFixed(h(i+1, key+1, len), 8);00065 m_k[i] = a+b;00066 m_k[i+1] = rotlFixed(a+2*b, 9);00067 }00068 00069 <a class="code" href="class_sec_block.html">SecBlock<word32></a> svec(2*len);00070 <span class="keywordflow">for</span> (i=0; i<len; i++)00071 svec[2*(len-i-1)] = ReedSolomon(key[2*i+1], key[2*i]);00072 <span class="keywordflow">for</span> (i=0; i<256; i++)00073 {00074 word32 t = h0(i, svec, len);00075 m_s[0][i] = mds[0][GETBYTE(t, 0)];00076 m_s[1][i] = mds[1][GETBYTE(t, 1)];00077 m_s[2][i] = mds[2][GETBYTE(t, 2)];00078 m_s[3][i] = mds[3][GETBYTE(t, 3)];00079 }00080 }00081 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>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>00084 <span class="preprocessor"></span>00085 <span class="preprocessor">#define ENCROUND(n, a, b, c, d) \</span>00086 <span class="preprocessor"> x = G1 (a); y = G2 (b); \</span>00087 <span class="preprocessor"> x += y; y += x + k[2 * (n) + 1]; \</span>00088 <span class="preprocessor"> (c) ^= x + k[2 * (n)]; \</span>00089 <span class="preprocessor"> (c) = rotrFixed(c, 1); \</span>00090 <span class="preprocessor"> (d) = rotlFixed(d, 1) ^ y</span>00091 <span class="preprocessor"></span>00092 <span class="preprocessor">#define ENCCYCLE(n) \</span>00093 <span class="preprocessor"> ENCROUND (2 * (n), a, b, c, d); \</span>00094 <span class="preprocessor"> ENCROUND (2 * (n) + 1, c, d, a, b)</span>00095 <span class="preprocessor"></span>00096 <span class="preprocessor">#define DECROUND(n, a, b, c, d) \</span>00097 <span class="preprocessor"> x = G1 (a); y = G2 (b); \</span>00098 <span class="preprocessor"> x += y; y += x; \</span>00099 <span class="preprocessor"> (d) ^= y + k[2 * (n) + 1]; \</span>00100 <span class="preprocessor"> (d) = rotrFixed(d, 1); \</span>00101 <span class="preprocessor"> (c) = rotlFixed(c, 1); \</span>00102 <span class="preprocessor"> (c) ^= (x + k[2 * (n)])</span>00103 <span class="preprocessor"></span>00104 <span class="preprocessor">#define DECCYCLE(n) \</span>00105 <span class="preprocessor"> DECROUND (2 * (n) + 1, c, d, a, b); \</span>00106 <span class="preprocessor"> DECROUND (2 * (n), a, b, c, d)</span>00107 <span class="preprocessor"></span>00108 <span class="keyword">typedef</span> BlockGetAndPut<word32, LittleEndian> Block;00109 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>00111 <span class="keyword"></span>{00112 word32 x, y, a, b, c, d;00113 00114 Block::Get(inBlock)(a)(b)(c)(d);00115 00116 a ^= m_k[0];00117 b ^= m_k[1];00118 c ^= m_k[2];00119 d ^= m_k[3];00120 00121 <span class="keyword">const</span> word32 *k = m_k+8;00122 ENCCYCLE (0);00123 ENCCYCLE (1);00124 ENCCYCLE (2);00125 ENCCYCLE (3);00126 ENCCYCLE (4);00127 ENCCYCLE (5);00128 ENCCYCLE (6);00129 ENCCYCLE (7);00130 00131 c ^= m_k[4];00132 d ^= m_k[5];00133 a ^= m_k[6];00134 b ^= m_k[7]; 00135 00136 Block::Put(xorBlock, outBlock)(c)(d)(a)(b);00137 }00138 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>00140 <span class="keyword"></span>{00141 word32 x, y, a, b, c, d;00142 00143 Block::Get(inBlock)(c)(d)(a)(b);00144 00145 c ^= m_k[4];00146 d ^= m_k[5];00147 a ^= m_k[6];00148 b ^= m_k[7];00149 00150 <span class="keyword">const</span> word32 *k = m_k+8;00151 DECCYCLE (7);00152 DECCYCLE (6);00153 DECCYCLE (5);00154 DECCYCLE (4);00155 DECCYCLE (3);00156 DECCYCLE (2);00157 DECCYCLE (1);00158 DECCYCLE (0);00159 00160 a ^= m_k[0];00161 b ^= m_k[1];00162 c ^= m_k[2];00163 d ^= m_k[3];00164 00165 Block::Put(xorBlock, outBlock)(a)(b)(c)(d);00166 }00167 00168 NAMESPACE_END</pre></div><hr size="1"><address style="align: right;"><small>Generated on Tue Jul 8 23:34:27 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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