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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++: rc5.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>rc5.cpp</h1><div class="fragment"><pre>00001 <span class="comment">// rc5.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="rc5_8h.html">rc5.h</a>"</span>00005 <span class="preprocessor">#include "misc.h"</span>00006 00007 NAMESPACE_BEGIN(CryptoPP)00008 00009 <span class="keywordtype">void</span> RC5::Base::UncheckedSetKey(CipherDir direction, <span class="keyword">const</span> byte *k, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> keylen, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rounds)00010 {00011 AssertValidKeyLength(keylen);00012 AssertValidRounds(rounds);00013 00014 r = rounds;00015 sTable.New(2*(r+1));00016 00017 <span class="keyword">static</span> <span class="keyword">const</span> RC5_WORD MAGIC_P = 0xb7e15163L; <span class="comment">// magic constant P for wordsize</span>00018 <span class="keyword">static</span> <span class="keyword">const</span> RC5_WORD MAGIC_Q = 0x9e3779b9L; <span class="comment">// magic constant Q for wordsize</span>00019 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">int</span> U=<span class="keyword">sizeof</span>(RC5_WORD);00020 00021 <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> c = STDMAX((keylen+U-1)/U, 1U); <span class="comment">// RC6 paper says c=1 if keylen==0</span>00022 <a class="code" href="class_sec_block.html">SecBlock<RC5_WORD></a> l(c);00023 00024 GetUserKey(LITTLE_ENDIAN_ORDER, l.<a class="code" href="class_sec_block.html#_sec_block_with_hinta7">begin</a>(), c, k, keylen);00025 00026 sTable[0] = MAGIC_P;00027 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> j=1; j<sTable.size();j++)00028 sTable[j] = sTable[j-1] + MAGIC_Q;00029 00030 RC5_WORD a=0, b=0;00031 <span class="keyword">const</span> <span class="keywordtype">unsigned</span> n = 3*STDMAX((<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>)sTable.size(), c);00032 00033 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> h=0; h < n; h++)00034 {00035 a = sTable[h % sTable.size()] = rotlFixed((sTable[h % sTable.size()] + a + b), 3);00036 b = l[h % c] = rotlMod((l[h % c] + a + b), (a+b));00037 }00038 }00039 00040 <span class="keyword">typedef</span> BlockGetAndPut<RC5::RC5_WORD, LittleEndian> Block;00041 00042 <span class="keywordtype">void</span> RC5::Enc::ProcessAndXorBlock(<span class="keyword">const</span> byte *inBlock, <span class="keyword">const</span> byte *xorBlock, byte *outBlock)<span class="keyword"> const</span>00043 <span class="keyword"></span>{00044 <span class="keyword">const</span> RC5_WORD *sptr = sTable;00045 RC5_WORD a, b;00046 00047 Block::Get(inBlock)(a)(b);00048 a += sptr[0];00049 b += sptr[1];00050 sptr += 2;00051 00052 <span class="keywordflow">for</span>(<span class="keywordtype">unsigned</span> i=0; i<r; i++)00053 {00054 a = rotlMod(a^b,b) + sptr[2*i+0];00055 b = rotlMod(a^b,a) + sptr[2*i+1];00056 }00057 00058 Block::Put(xorBlock, outBlock)(a)(b);00059 }00060 00061 <span class="keywordtype">void</span> RC5::Dec::ProcessAndXorBlock(<span class="keyword">const</span> byte *inBlock, <span class="keyword">const</span> byte *xorBlock, byte *outBlock)<span class="keyword"> const</span>00062 <span class="keyword"></span>{00063 <span class="keyword">const</span> RC5_WORD *sptr = sTable.end();00064 RC5_WORD a, b;00065 00066 Block::Get(inBlock)(a)(b);00067 00068 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> i=0; i<r; i++)00069 {00070 sptr-=2;00071 b = rotrMod(b-sptr[1], a) ^ a;00072 a = rotrMod(a-sptr[0], b) ^ b;00073 }00074 b -= sTable[1];00075 a -= sTable[0];00076 00077 Block::Put(xorBlock, outBlock)(a)(b);00078 }00079 00080 NAMESPACE_END</pre></div><hr size="1"><address style="align: right;"><small>Generated on Tue Jul 8 23:34:23 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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