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<h1>rng.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// rng.cpp - written and placed in the public domain by Wei Dai</span>
<a name="l00002"></a>00002
<a name="l00003"></a>00003 <span class="preprocessor">#include "pch.h"</span>
<a name="l00004"></a>00004
<a name="l00005"></a>00005 <span class="preprocessor">#include "rng.h"</span>
<a name="l00006"></a>00006 <span class="preprocessor">#include "<a class="code" href="fips140_8h.html">fips140.h</a>"</span>
<a name="l00007"></a>00007
<a name="l00008"></a>00008 <span class="preprocessor">#include <time.h></span>
<a name="l00009"></a>00009 <span class="preprocessor">#include <math.h></span>
<a name="l00010"></a>00010
<a name="l00011"></a>00011 NAMESPACE_BEGIN(CryptoPP)
<a name="l00012"></a>00012
<a name="l00013"></a>00013 <span class="comment">// linear congruential generator</span>
<a name="l00014"></a>00014 <span class="comment">// originally by William S. England</span>
<a name="l00015"></a>00015
<a name="l00016"></a>00016 <span class="comment">// do not use for cryptographic purposes</span>
<a name="l00017"></a>00017
<a name="l00018"></a>00018 <span class="comment">/*</span>
<a name="l00019"></a>00019 <span class="comment">** Original_numbers are the original published m and q in the</span>
<a name="l00020"></a>00020 <span class="comment">** ACM article above. John Burton has furnished numbers for</span>
<a name="l00021"></a>00021 <span class="comment">** a reportedly better generator. The new numbers are now</span>
<a name="l00022"></a>00022 <span class="comment">** used in this program by default.</span>
<a name="l00023"></a>00023 <span class="comment">*/</span>
<a name="l00024"></a>00024
<a name="l00025"></a>00025 <span class="preprocessor">#ifndef LCRNG_ORIGINAL_NUMBERS</span>
<a name="l00026"></a>00026 <span class="preprocessor"></span><span class="keyword">const</span> word32 LC_RNG::m=2147483647L;
<a name="l00027"></a>00027 <span class="keyword">const</span> word32 LC_RNG::q=44488L;
<a name="l00028"></a>00028
<a name="l00029"></a>00029 <span class="keyword">const</span> word16 LC_RNG::a=(<span class="keywordtype">unsigned</span> int)48271L;
<a name="l00030"></a>00030 <span class="keyword">const</span> word16 LC_RNG::r=3399;
<a name="l00031"></a>00031 <span class="preprocessor">#else</span>
<a name="l00032"></a>00032 <span class="preprocessor"></span><span class="keyword">const</span> word32 LC_RNG::m=2147483647L;
<a name="l00033"></a>00033 <span class="keyword">const</span> word32 LC_RNG::q=127773L;
<a name="l00034"></a>00034
<a name="l00035"></a>00035 <span class="keyword">const</span> word16 LC_RNG::a=16807;
<a name="l00036"></a>00036 <span class="keyword">const</span> word16 LC_RNG::r=2836;
<a name="l00037"></a>00037 <span class="preprocessor">#endif</span>
<a name="l00038"></a>00038 <span class="preprocessor"></span>
<a name="l00039"></a><a class="code" href="class_l_c___r_n_g.html#ab2f22bacb77dab778008f3301daa3ad6">00039</a> <span class="keywordtype">void</span> <a class="code" href="class_l_c___r_n_g.html#ab2f22bacb77dab778008f3301daa3ad6" title="generate random array of bytes">LC_RNG::GenerateBlock</a>(byte *output, <span class="keywordtype">size_t</span> size)
<a name="l00040"></a>00040 {
<a name="l00041"></a>00041 <span class="keywordflow">while</span> (size--)
<a name="l00042"></a>00042 {
<a name="l00043"></a>00043 word32 hi = seed/q;
<a name="l00044"></a>00044 word32 lo = seed%q;
<a name="l00045"></a>00045
<a name="l00046"></a>00046 <span class="keywordtype">long</span> test = a*lo - r*hi;
<a name="l00047"></a>00047
<a name="l00048"></a>00048 <span class="keywordflow">if</span> (test > 0)
<a name="l00049"></a>00049 seed = test;
<a name="l00050"></a>00050 <span class="keywordflow">else</span>
<a name="l00051"></a>00051 seed = test+ m;
<a name="l00052"></a>00052
<a name="l00053"></a>00053 *output++ = (GETBYTE(seed, 0) ^ GETBYTE(seed, 1) ^ GETBYTE(seed, 2) ^ GETBYTE(seed, 3));
<a name="l00054"></a>00054 }
<a name="l00055"></a>00055 }
<a name="l00056"></a>00056
<a name="l00057"></a>00057 <span class="comment">// ********************************************************</span>
<a name="l00058"></a>00058
<a name="l00059"></a>00059 <span class="preprocessor">#ifndef CRYPTOPP_IMPORTS</span>
<a name="l00060"></a>00060 <span class="preprocessor"></span>
<a name="l00061"></a>00061 X917RNG::X917RNG(<a class="code" href="class_block_transformation.html" title="interface for the data processing part of block ciphers">BlockTransformation</a> *c, <span class="keyword">const</span> byte *seed, <span class="keyword">const</span> byte *deterministicTimeVector)
<a name="l00062"></a>00062 : cipher(c),
<a name="l00063"></a>00063 S(cipher->BlockSize()),
<a name="l00064"></a>00064 dtbuf(S),
<a name="l00065"></a>00065 randseed(seed, S),
<a name="l00066"></a>00066 m_lastBlock(S),
<a name="l00067"></a>00067 m_deterministicTimeVector(deterministicTimeVector, deterministicTimeVector ? S : 0)
<a name="l00068"></a>00068 {
<a name="l00069"></a>00069 <span class="keywordflow">if</span> (!deterministicTimeVector)
<a name="l00070"></a>00070 {
<a name="l00071"></a>00071 time_t tstamp1 = time(0);
<a name="l00072"></a>00072 xorbuf(dtbuf, (byte *)&tstamp1, UnsignedMin(<span class="keyword">sizeof</span>(tstamp1), S));
<a name="l00073"></a>00073 cipher->ProcessBlock(dtbuf);
<a name="l00074"></a>00074 clock_t tstamp2 = clock();
<a name="l00075"></a>00075 xorbuf(dtbuf, (byte *)&tstamp2, UnsignedMin(<span class="keyword">sizeof</span>(tstamp2), S));
<a name="l00076"></a>00076 cipher->ProcessBlock(dtbuf);
<a name="l00077"></a>00077 }
<a name="l00078"></a>00078
<a name="l00079"></a>00079 <span class="comment">// for FIPS 140-2</span>
<a name="l00080"></a>00080 <a class="code" href="class_l_c___r_n_g.html#ab2f22bacb77dab778008f3301daa3ad6" title="generate random array of bytes">GenerateBlock</a>(m_lastBlock, S);
<a name="l00081"></a>00081 }
<a name="l00082"></a>00082
<a name="l00083"></a><a class="code" href="class_x917_r_n_g.html#a5b84223763a1f90ddc55e87769df7bf9">00083</a> <span class="keywordtype">void</span> <a class="code" href="class_x917_r_n_g.html#a5b84223763a1f90ddc55e87769df7bf9" title="generate random bytes as input to a BufferedTransformation">X917RNG::GenerateIntoBufferedTransformation</a>(<a class="code" href="class_buffered_transformation.html" title="interface for buffered transformations">BufferedTransformation</a> &target, <span class="keyword">const</span> std::string &channel, lword size)
<a name="l00084"></a>00084 {
<a name="l00085"></a>00085 <span class="keywordflow">while</span> (size > 0)
<a name="l00086"></a>00086 {
<a name="l00087"></a>00087 <span class="comment">// calculate new enciphered timestamp</span>
<a name="l00088"></a>00088 <span class="keywordflow">if</span> (m_deterministicTimeVector.size())
<a name="l00089"></a>00089 {
<a name="l00090"></a>00090 cipher->ProcessBlock(m_deterministicTimeVector, dtbuf);
<a name="l00091"></a>00091 IncrementCounterByOne(m_deterministicTimeVector, S);
<a name="l00092"></a>00092 }
<a name="l00093"></a>00093 <span class="keywordflow">else</span>
<a name="l00094"></a>00094 {
<a name="l00095"></a>00095 clock_t c = clock();
<a name="l00096"></a>00096 xorbuf(dtbuf, (byte *)&c, UnsignedMin(<span class="keyword">sizeof</span>(c), S));
<a name="l00097"></a>00097 time_t t = time(NULL);
<a name="l00098"></a>00098 xorbuf(dtbuf+S-UnsignedMin(<span class="keyword">sizeof</span>(t), S), (byte *)&t, UnsignedMin(<span class="keyword">sizeof</span>(t), S));
<a name="l00099"></a>00099 cipher->ProcessBlock(dtbuf);
<a name="l00100"></a>00100 }
<a name="l00101"></a>00101
<a name="l00102"></a>00102 <span class="comment">// combine enciphered timestamp with seed</span>
<a name="l00103"></a>00103 xorbuf(randseed, dtbuf, S);
<a name="l00104"></a>00104
<a name="l00105"></a>00105 <span class="comment">// generate a new block of random bytes</span>
<a name="l00106"></a>00106 cipher->ProcessBlock(randseed);
<a name="l00107"></a>00107 <span class="keywordflow">if</span> (memcmp(m_lastBlock, randseed, S) == 0)
<a name="l00108"></a>00108 <span class="keywordflow">throw</span> <a class="code" href="class_self_test_failure.html" title="exception thrown when a crypto algorithm is used after a self test fails">SelfTestFailure</a>(<span class="stringliteral">"X917RNG: Continuous random number generator test failed."</span>);
<a name="l00109"></a>00109
<a name="l00110"></a>00110 <span class="comment">// output random bytes</span>
<a name="l00111"></a>00111 <span class="keywordtype">size_t</span> len = UnsignedMin(S, size);
<a name="l00112"></a>00112 target.ChannelPut(channel, randseed, len);
<a name="l00113"></a>00113 size -= len;
<a name="l00114"></a>00114
<a name="l00115"></a>00115 <span class="comment">// compute new seed vector</span>
<a name="l00116"></a>00116 memcpy(m_lastBlock, randseed, S);
<a name="l00117"></a>00117 xorbuf(randseed, dtbuf, S);
<a name="l00118"></a>00118 cipher->ProcessBlock(randseed);
<a name="l00119"></a>00119 }
<a name="l00120"></a>00120 }
<a name="l00121"></a>00121
<a name="l00122"></a>00122 <span class="preprocessor">#endif</span>
<a name="l00123"></a>00123 <span class="preprocessor"></span>
<a name="l00124"></a>00124 MaurerRandomnessTest::MaurerRandomnessTest()
<a name="l00125"></a>00125 : sum(0.0), n(0)
<a name="l00126"></a>00126 {
<a name="l00127"></a>00127 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> i=0; i<V; i++)
<a name="l00128"></a>00128 tab[i] = 0;
<a name="l00129"></a>00129 }
<a name="l00130"></a>00130
<a name="l00131"></a><a class="code" href="class_maurer_randomness_test.html#ae2629df58de48eafc8b8d9f0b060ff98">00131</a> <span class="keywordtype">size_t</span> <a class="code" href="class_maurer_randomness_test.html#ae2629df58de48eafc8b8d9f0b060ff98" title="input multiple bytes for blocking or non-blocking processing">MaurerRandomnessTest::Put2</a>(<span class="keyword">const</span> byte *inString, <span class="keywordtype">size_t</span> length, <span class="keywordtype">int</span> messageEnd, <span class="keywordtype">bool</span> blocking)
<a name="l00132"></a>00132 {
<a name="l00133"></a>00133 <span class="keywordflow">while</span> (length--)
<a name="l00134"></a>00134 {
<a name="l00135"></a>00135 byte inByte = *inString++;
<a name="l00136"></a>00136 <span class="keywordflow">if</span> (n >= Q)
<a name="l00137"></a>00137 sum += log(<span class="keywordtype">double</span>(n - tab[inByte]));
<a name="l00138"></a>00138 tab[inByte] = n;
<a name="l00139"></a>00139 n++;
<a name="l00140"></a>00140 }
<a name="l00141"></a>00141 <span class="keywordflow">return</span> 0;
<a name="l00142"></a>00142 }
<a name="l00143"></a>00143
<a name="l00144"></a>00144 <span class="keywordtype">double</span> MaurerRandomnessTest::GetTestValue()<span class="keyword"> const</span>
<a name="l00145"></a>00145 <span class="keyword"></span>{
<a name="l00146"></a>00146 <span class="keywordflow">if</span> (BytesNeeded() > 0)
<a name="l00147"></a>00147 <span class="keywordflow">throw</span> <a class="code" href="class_exception.html" title="base class for all exceptions thrown by Crypto++">Exception</a>(<a class="code" href="class_exception.html#a8e53909d979479380e0274807c074c0aa27d9ee7704100a88e4ae4adcc4072015" title="some error not belong to any of the above categories">Exception::OTHER_ERROR</a>, <span class="stringliteral">"MaurerRandomnessTest: "</span> + IntToString(BytesNeeded()) + <span class="stringliteral">" more bytes of input needed"</span>);
<a name="l00148"></a>00148
<a name="l00149"></a>00149 <span class="keywordtype">double</span> fTu = (sum/(n-Q))/log(2.0); <span class="comment">// this is the test value defined by Maurer</span>
<a name="l00150"></a>00150
<a name="l00151"></a>00151 <span class="keywordtype">double</span> value = fTu * 0.1392; <span class="comment">// arbitrarily normalize it to</span>
<a name="l00152"></a>00152 <span class="keywordflow">return</span> value > 1.0 ? 1.0 : value; <span class="comment">// a number between 0 and 1</span>
<a name="l00153"></a>00153 }
<a name="l00154"></a>00154
<a name="l00155"></a>00155 NAMESPACE_END
</pre></div></div>
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