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<div class="title">rc6.cpp</div> </div>
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<div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// rc6.cpp - written and placed in the public domain by Sean Woods</span>
<a name="l00002"></a>00002 <span class="comment">// based on Wei Dai's RC5 code.</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="rc6_8h.html">rc6.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 void <a class="code" href="class_r_c6.html" title="RC6">RC6</a>::Base::UncheckedSetKey(const byte *k, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> keylen, const <a class="code" href="class_name_value_pairs.html" title="interface for retrieving values given their names">NameValuePairs</a> &params)
<a name="l00011"></a>00011 {
<a name="l00012"></a>00012 AssertValidKeyLength(keylen);
<a name="l00013"></a>00013
<a name="l00014"></a>00014 r = GetRoundsAndThrowIfInvalid(params, <span class="keyword">this</span>);
<a name="l00015"></a>00015 sTable.New(2*(r+2));
<a name="l00016"></a>00016
<a name="l00017"></a>00017 <span class="keyword">static</span> <span class="keyword">const</span> RC6_WORD MAGIC_P = 0xb7e15163L; <span class="comment">// magic constant P for wordsize</span>
<a name="l00018"></a>00018 <span class="keyword">static</span> <span class="keyword">const</span> RC6_WORD MAGIC_Q = 0x9e3779b9L; <span class="comment">// magic constant Q for wordsize</span>
<a name="l00019"></a>00019 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">int</span> U=<span class="keyword">sizeof</span>(RC6_WORD);
<a name="l00020"></a>00020
<a name="l00021"></a>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>
<a name="l00022"></a>00022 <a class="code" href="class_sec_block.html">SecBlock<RC6_WORD></a> l(c);
<a name="l00023"></a>00023
<a name="l00024"></a>00024 GetUserKey(LITTLE_ENDIAN_ORDER, l.begin(), c, k, keylen);
<a name="l00025"></a>00025
<a name="l00026"></a>00026 sTable[0] = MAGIC_P;
<a name="l00027"></a>00027 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> j=1; j<sTable.size();j++)
<a name="l00028"></a>00028 sTable[j] = sTable[j-1] + MAGIC_Q;
<a name="l00029"></a>00029
<a name="l00030"></a>00030 RC6_WORD a=0, b=0;
<a name="l00031"></a>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);
<a name="l00032"></a>00032
<a name="l00033"></a>00033 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> h=0; h < n; h++)
<a name="l00034"></a>00034 {
<a name="l00035"></a>00035 a = sTable[h % sTable.size()] = rotlFixed((sTable[h % sTable.size()] + a + b), 3);
<a name="l00036"></a>00036 b = l[h % c] = rotlMod((l[h % c] + a + b), (a+b));
<a name="l00037"></a>00037 }
<a name="l00038"></a>00038 }
<a name="l00039"></a>00039
<a name="l00040"></a>00040 <span class="keyword">typedef</span> <a class="code" href="struct_block_get_and_put.html">BlockGetAndPut<RC6::RC6_WORD, LittleEndian></a> <a class="code" href="struct_block_get_and_put.html">Block</a>;
<a name="l00041"></a>00041
<a name="l00042"></a>00042 <span class="keywordtype">void</span> RC6::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="l00043"></a>00043 <span class="keyword"></span>{
<a name="l00044"></a>00044 <span class="keyword">const</span> RC6_WORD *sptr = sTable;
<a name="l00045"></a>00045 RC6_WORD a, b, c, d, t, u;
<a name="l00046"></a>00046
<a name="l00047"></a>00047 Block::Get(inBlock)(a)(b)(c)(d);
<a name="l00048"></a>00048 b += sptr[0];
<a name="l00049"></a>00049 d += sptr[1];
<a name="l00050"></a>00050 sptr += 2;
<a name="l00051"></a>00051
<a name="l00052"></a>00052 <span class="keywordflow">for</span>(<span class="keywordtype">unsigned</span> i=0; i<r; i++)
<a name="l00053"></a>00053 {
<a name="l00054"></a>00054 t = rotlFixed(b*(2*b+1), 5);
<a name="l00055"></a>00055 u = rotlFixed(d*(2*d+1), 5);
<a name="l00056"></a>00056 a = rotlMod(a^t,u) + sptr[0];
<a name="l00057"></a>00057 c = rotlMod(c^u,t) + sptr[1];
<a name="l00058"></a>00058 t = a; a = b; b = c; c = d; d = t;
<a name="l00059"></a>00059 sptr += 2;
<a name="l00060"></a>00060 }
<a name="l00061"></a>00061
<a name="l00062"></a>00062 a += sptr[0];
<a name="l00063"></a>00063 c += sptr[1];
<a name="l00064"></a>00064
<a name="l00065"></a>00065 <a class="code" href="class_put_block.html">Block::Put</a>(xorBlock, outBlock)(a)(b)(c)(d);
<a name="l00066"></a>00066 }
<a name="l00067"></a>00067
<a name="l00068"></a>00068 <span class="keywordtype">void</span> RC6::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="l00069"></a>00069 <span class="keyword"></span>{
<a name="l00070"></a>00070 <span class="keyword">const</span> RC6_WORD *sptr = sTable.end();
<a name="l00071"></a>00071 RC6_WORD a, b, c, d, t, u;
<a name="l00072"></a>00072
<a name="l00073"></a>00073 Block::Get(inBlock)(a)(b)(c)(d);
<a name="l00074"></a>00074
<a name="l00075"></a>00075 sptr -= 2;
<a name="l00076"></a>00076 c -= sptr[1];
<a name="l00077"></a>00077 a -= sptr[0];
<a name="l00078"></a>00078
<a name="l00079"></a>00079 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> i=0; i < r; i++)
<a name="l00080"></a>00080 {
<a name="l00081"></a>00081 sptr -= 2;
<a name="l00082"></a>00082 t = a; a = d; d = c; c = b; b = t;
<a name="l00083"></a>00083 u = rotlFixed(d*(2*d+1), 5);
<a name="l00084"></a>00084 t = rotlFixed(b*(2*b+1), 5);
<a name="l00085"></a>00085 c = rotrMod(c-sptr[1], t) ^ u;
<a name="l00086"></a>00086 a = rotrMod(a-sptr[0], u) ^ t;
<a name="l00087"></a>00087 }
<a name="l00088"></a>00088
<a name="l00089"></a>00089 sptr -= 2;
<a name="l00090"></a>00090 d -= sTable[1];
<a name="l00091"></a>00091 b -= sTable[0];
<a name="l00092"></a>00092
<a name="l00093"></a>00093 <a class="code" href="class_put_block.html">Block::Put</a>(xorBlock, outBlock)(a)(b)(c)(d);
<a name="l00094"></a>00094 }
<a name="l00095"></a>00095
<a name="l00096"></a>00096 NAMESPACE_END
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