ec2n_8cpp-source.html

Crypto++是一个非常强大的密码学库,主要是功能全

00146         <span class="keywordflow">return</span> pass;
00147 }
00148 
00149 <span class="keywordtype">bool</span> EC2N::VerifyPoint(<span class="keyword">const</span> Point &amp;P)<span class="keyword"> const</span>
00150 <span class="keyword"></span>{
00151         <span class="keyword">const</span> FieldElement &amp;x = P.x, &amp;y = P.y;
00152         <span class="keywordflow">return</span> P.identity || 
00153                 (x.CoefficientCount() &lt;= m_field-&gt;MaxElementBitLength()
00154                 &amp;&amp; y.CoefficientCount() &lt;= m_field-&gt;MaxElementBitLength()
00155                 &amp;&amp; !(((x+m_a)*x*x+m_b-(x+y)*y)%m_field-&gt;GetModulus()));
00156 }
00157 
00158 <span class="keywordtype">bool</span> EC2N::Equal(<span class="keyword">const</span> Point &amp;P, <span class="keyword">const</span> Point &amp;Q)<span class="keyword"> const</span>
00159 <span class="keyword"></span>{
00160         <span class="keywordflow">if</span> (P.identity &amp;&amp; Q.identity)
00161                 <span class="keywordflow">return</span> <span class="keyword">true</span>;
00162 
00163         <span class="keywordflow">if</span> (P.identity &amp;&amp; !Q.identity)
00164                 <span class="keywordflow">return</span> <span class="keyword">false</span>;
00165 
00166         <span class="keywordflow">if</span> (!P.identity &amp;&amp; Q.identity)
00167                 <span class="keywordflow">return</span> <span class="keyword">false</span>;
00168 
00169         <span class="keywordflow">return</span> (m_field-&gt;Equal(P.x,Q.x) &amp;&amp; m_field-&gt;Equal(P.y,Q.y));
00170 }
00171 
00172 <span class="keyword">const</span> <a class="code" href="struct_e_c2_n_point.html">EC2N::Point</a>&amp; EC2N::Identity()<span class="keyword"> const</span>
00173 <span class="keyword"></span>{
00174         <span class="keyword">static</span> <span class="keyword">const</span> Point zero;
00175         <span class="keywordflow">return</span> zero;
00176 }
00177 
00178 <span class="keyword">const</span> <a class="code" href="struct_e_c2_n_point.html">EC2N::Point</a>&amp; EC2N::Inverse(<span class="keyword">const</span> Point &amp;P)<span class="keyword"> const</span>
00179 <span class="keyword"></span>{
00180         <span class="keywordflow">if</span> (P.identity)
00181                 <span class="keywordflow">return</span> P;
00182         <span class="keywordflow">else</span>
00183         {
00184                 m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo0">identity</a> = <span class="keyword">false</span>;
00185                 m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo2">y</a> = m_field-&gt;Add(P.x, P.y);
00186                 m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo1">x</a> = P.x;
00187                 <span class="keywordflow">return</span> m_R;
00188         }
00189 }
00190 
00191 <span class="keyword">const</span> <a class="code" href="struct_e_c2_n_point.html">EC2N::Point</a>&amp; EC2N::Add(<span class="keyword">const</span> Point &amp;P, <span class="keyword">const</span> Point &amp;Q)<span class="keyword"> const</span>
00192 <span class="keyword"></span>{
00193         <span class="keywordflow">if</span> (P.identity) <span class="keywordflow">return</span> Q;
00194         <span class="keywordflow">if</span> (Q.identity) <span class="keywordflow">return</span> P;
00195         <span class="keywordflow">if</span> (Equal(P, Q)) <span class="keywordflow">return</span> Double(P);
00196         <span class="keywordflow">if</span> (m_field-&gt;Equal(P.x, Q.x) &amp;&amp; m_field-&gt;Equal(P.y, m_field-&gt;Add(Q.x, Q.y))) <span class="keywordflow">return</span> Identity();
00197 
00198         FieldElement t = m_field-&gt;Add(P.y, Q.y);
00199         t = m_field-&gt;Divide(t, m_field-&gt;Add(P.x, Q.x));
00200         FieldElement x = m_field-&gt;Square(t);
00201         m_field-&gt;Accumulate(x, t);
00202         m_field-&gt;Accumulate(x, Q.x);
00203         m_field-&gt;Accumulate(x, m_a);
00204         m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo2">y</a> = m_field-&gt;Add(P.y, m_field-&gt;Multiply(t, x));
00205         m_field-&gt;Accumulate(x, P.x);
00206         m_field-&gt;Accumulate(m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo2">y</a>, x);
00207 
00208         m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo1">x</a>.<a class="code" href="class_polynomial_mod2.html#_polynomial_mod2z25_14">swap</a>(x);
00209         m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo0">identity</a> = <span class="keyword">false</span>;
00210         <span class="keywordflow">return</span> m_R;
00211 }
00212 
00213 <span class="keyword">const</span> <a class="code" href="struct_e_c2_n_point.html">EC2N::Point</a>&amp; EC2N::Double(<span class="keyword">const</span> Point &amp;P)<span class="keyword"> const</span>
00214 <span class="keyword"></span>{
00215         <span class="keywordflow">if</span> (P.identity) <span class="keywordflow">return</span> P;
00216         <span class="keywordflow">if</span> (!m_field-&gt;IsUnit(P.x)) <span class="keywordflow">return</span> Identity();
00217 
00218         FieldElement t = m_field-&gt;Divide(P.y, P.x);
00219         m_field-&gt;Accumulate(t, P.x);
00220         m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo2">y</a> = m_field-&gt;Square(P.x);
00221         m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo1">x</a> = m_field-&gt;Square(t);
00222         m_field-&gt;Accumulate(m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo1">x</a>, t);
00223         m_field-&gt;Accumulate(m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo1">x</a>, m_a);
00224         m_field-&gt;Accumulate(m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo2">y</a>, m_field-&gt;Multiply(t, m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo1">x</a>));
00225         m_field-&gt;Accumulate(m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo2">y</a>, m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo1">x</a>);
00226 
00227         m_R.<a class="code" href="struct_e_c2_n_point.html#_e_c2_n_pointo0">identity</a> = <span class="keyword">false</span>;
00228         <span class="keywordflow">return</span> m_R;
00229 }
00230 
00231 <span class="comment">// ********************************************************</span>
00232 
00233 <span class="comment">/*</span>
00234 <span class="comment">EcPrecomputation&lt;EC2N&gt;&amp; EcPrecomputation&lt;EC2N&gt;::operator=(const EcPrecomputation&lt;EC2N&gt; &amp;rhs)</span>
00235 <span class="comment">{</span>
00236 <span class="comment">        m_ec = rhs.m_ec;</span>
00237 <span class="comment">        m_ep = rhs.m_ep;</span>
00238 <span class="comment">        m_ep.m_group = m_ec.get();</span>
00239 <span class="comment">        return *this;</span>
00240 <span class="comment">}</span>
00241 <span class="comment"></span>
00242 <span class="comment">void EcPrecomputation&lt;EC2N&gt;::SetCurveAndBase(const EC2N &amp;ec, const EC2N::Point &amp;base)</span>
00243 <span class="comment">{</span>
00244 <span class="comment">        m_ec.reset(new EC2N(ec));</span>
00245 <span class="comment">        m_ep.SetGroupAndBase(*m_ec, base);</span>
00246 <span class="comment">}</span>
00247 <span class="comment"></span>
00248 <span class="comment">void EcPrecomputation&lt;EC2N&gt;::Precompute(unsigned int maxExpBits, unsigned int storage)</span>
00249 <span class="comment">{</span>
00250 <span class="comment">        m_ep.Precompute(maxExpBits, storage);</span>
00251 <span class="comment">}</span>
00252 <span class="comment"></span>
00253 <span class="comment">void EcPrecomputation&lt;EC2N&gt;::Load(BufferedTransformation &amp;bt)</span>
00254 <span class="comment">{</span>
00255 <span class="comment">        BERSequenceDecoder seq(bt);</span>
00256 <span class="comment">        word32 version;</span>
00257 <span class="comment">        BERDecodeUnsigned&lt;word32&gt;(seq, version, INTEGER, 1, 1);</span>
00258 <span class="comment">        m_ep.m_exponentBase.BERDecode(seq);</span>
00259 <span class="comment">        m_ep.m_windowSize = m_ep.m_exponentBase.BitCount() - 1;</span>
00260 <span class="comment">        m_ep.m_bases.clear();</span>
00261 <span class="comment">        while (!seq.EndReached())</span>
00262 <span class="comment">                m_ep.m_bases.push_back(m_ec-&gt;BERDecodePoint(seq));</span>
00263 <span class="comment">        seq.MessageEnd();</span>
00264 <span class="comment">}</span>
00265 <span class="comment"></span>
00266 <span class="comment">void EcPrecomputation&lt;EC2N&gt;::Save(BufferedTransformation &amp;bt) const</span>
00267 <span class="comment">{</span>
00268 <span class="comment">        DERSequenceEncoder seq(bt);</span>
00269 <span class="comment">        DEREncodeUnsigned&lt;word32&gt;(seq, 1);      // version</span>
00270 <span class="comment">        m_ep.m_exponentBase.DEREncode(seq);</span>
00271 <span class="comment">        for (unsigned i=0; i&lt;m_ep.m_bases.size(); i++)</span>
00272 <span class="comment">                m_ec-&gt;DEREncodePoint(seq, m_ep.m_bases[i]);</span>
00273 <span class="comment">        seq.MessageEnd();</span>
00274 <span class="comment">}</span>
00275 <span class="comment"></span>
00276 <span class="comment">EC2N::Point EcPrecomputation&lt;EC2N&gt;::Exponentiate(const Integer &amp;exponent) const</span>
00277 <span class="comment">{</span>
00278 <span class="comment">        return m_ep.Exponentiate(exponent);</span>
00279 <span class="comment">}</span>
00280 <span class="comment"></span>
00281 <span class="comment">EC2N::Point EcPrecomputation&lt;EC2N&gt;::CascadeExponentiate(const Integer &amp;exponent, const DL_FixedBasePrecomputation&lt;Element&gt; &amp;pc2, const Integer &amp;exponent2) const</span>
00282 <span class="comment">{</span>
00283 <span class="comment">        return m_ep.CascadeExponentiate(exponent, static_cast&lt;const EcPrecomputation&lt;EC2N&gt; &amp;&gt;(pc2).m_ep, exponent2);</span>
00284 <span class="comment">}</span>
00285 <span class="comment">*/</span>
00286 
00287 NAMESPACE_END
00288 
00289 <span class="preprocessor">#endif</span>
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