📄 ec2n_8cpp-source.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"><title>Crypto++: ec2n.cpp Source File</title><link href="doxygen.css" rel="stylesheet" type="text/css"><link href="tabs.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.5.2 --><div class="tabs"> <ul> <li><a href="index.html"><span>Main Page</span></a></li> <li><a href="namespaces.html"><span>Namespaces</span></a></li> <li><a href="classes.html"><span>Classes</span></a></li> <li class="current"><a href="files.html"><span>Files</span></a></li> </ul></div><div class="tabs"> <ul> <li><a href="files.html"><span>File List</span></a></li> <li><a href="globals.html"><span>File Members</span></a></li> </ul></div><h1>ec2n.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// ec2n.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">#ifndef CRYPTOPP_IMPORTS</span><a name="l00006"></a>00006 <span class="preprocessor"></span><a name="l00007"></a>00007 <span class="preprocessor">#include "ec2n.h"</span><a name="l00008"></a>00008 <span class="preprocessor">#include "asn.h"</span><a name="l00009"></a>00009 <a name="l00010"></a>00010 <span class="preprocessor">#include "algebra.cpp"</span><a name="l00011"></a>00011 <span class="preprocessor">#include "eprecomp.cpp"</span><a name="l00012"></a>00012 <a name="l00013"></a>00013 NAMESPACE_BEGIN(CryptoPP)<a name="l00014"></a>00014 <a name="l00015"></a><a class="code" href="class_e_c2_n.html#92b1fd124cd5babd51d0886668336b7e">00015</a> <a class="code" href="class_e_c2_n.html" title="Elliptic Curve over GF(2^n).">EC2N</a>::<a class="code" href="class_e_c2_n.html" title="Elliptic Curve over GF(2^n).">EC2N</a>(<a class="code" href="class_buffered_transformation.html" title="interface for buffered transformations">BufferedTransformation</a> &bt)<a name="l00016"></a>00016 : m_field(BERDecodeGF2NP(bt))<a name="l00017"></a>00017 {<a name="l00018"></a>00018 <a class="code" href="class_b_e_r_sequence_decoder.html" title="BER Sequence Decoder.">BERSequenceDecoder</a> seq(bt);<a name="l00019"></a>00019 m_field->BERDecodeElement(seq, m_a);<a name="l00020"></a>00020 m_field->BERDecodeElement(seq, m_b);<a name="l00021"></a>00021 <span class="comment">// skip optional seed</span><a name="l00022"></a>00022 <span class="keywordflow">if</span> (!seq.<a class="code" href="class_b_e_r_general_decoder.html#04f4fe90e88584b1cebffd32e149bfbc">EndReached</a>())<a name="l00023"></a>00023 BERDecodeOctetString(seq, TheBitBucket());<a name="l00024"></a>00024 seq.<a class="code" href="class_b_e_r_general_decoder.html#40b14625c98ac7febb8ca218d02358ad">MessageEnd</a>();<a name="l00025"></a>00025 }<a name="l00026"></a>00026 <a name="l00027"></a><a class="code" href="class_e_c2_n.html#e90045af196aff7edc035a6051f1640f">00027</a> <span class="keywordtype">void</span> <a class="code" href="class_e_c2_n.html#e90045af196aff7edc035a6051f1640f">EC2N::DEREncode</a>(<a class="code" href="class_buffered_transformation.html" title="interface for buffered transformations">BufferedTransformation</a> &bt)<span class="keyword"> const</span><a name="l00028"></a>00028 <span class="keyword"></span>{<a name="l00029"></a>00029 m_field->DEREncode(bt);<a name="l00030"></a>00030 <a class="code" href="class_d_e_r_sequence_encoder.html" title="DER Sequence Encoder.">DERSequenceEncoder</a> seq(bt);<a name="l00031"></a>00031 m_field->DEREncodeElement(seq, m_a);<a name="l00032"></a>00032 m_field->DEREncodeElement(seq, m_b);<a name="l00033"></a>00033 seq.<a class="code" href="class_d_e_r_general_encoder.html#cb5f1a94ba97027c603b019bd5228510">MessageEnd</a>();<a name="l00034"></a>00034 }<a name="l00035"></a>00035 <a name="l00036"></a><a class="code" href="class_e_c2_n.html#17e4228b2569a376ac29e819f09d48e3">00036</a> <span class="keywordtype">bool</span> <a class="code" href="class_e_c2_n.html#e9fead90e9048d454916868ef4e55cb6">EC2N::DecodePoint</a>(<a class="code" href="struct_e_c2_n_point.html" title="Elliptic Curve Point.">EC2N::Point</a> &P, <span class="keyword">const</span> byte *encodedPoint, <span class="keywordtype">size_t</span> encodedPointLen)<span class="keyword"> const</span><a name="l00037"></a>00037 <span class="keyword"></span>{<a name="l00038"></a>00038 <a class="code" href="class_string_store.html" title="string-based implementation of Store interface">StringStore</a> store(encodedPoint, encodedPointLen);<a name="l00039"></a>00039 <span class="keywordflow">return</span> <a class="code" href="class_e_c2_n.html#e9fead90e9048d454916868ef4e55cb6">DecodePoint</a>(P, store, encodedPointLen);<a name="l00040"></a>00040 }<a name="l00041"></a>00041 <a name="l00042"></a><a class="code" href="class_e_c2_n.html#e9fead90e9048d454916868ef4e55cb6">00042</a> <span class="keywordtype">bool</span> <a class="code" href="class_e_c2_n.html#e9fead90e9048d454916868ef4e55cb6">EC2N::DecodePoint</a>(<a class="code" href="struct_e_c2_n_point.html" title="Elliptic Curve Point.">EC2N::Point</a> &P, <a class="code" href="class_buffered_transformation.html" title="interface for buffered transformations">BufferedTransformation</a> &bt, <span class="keywordtype">size_t</span> encodedPointLen)<span class="keyword"> const</span><a name="l00043"></a>00043 <span class="keyword"></span>{<a name="l00044"></a>00044 byte type;<a name="l00045"></a>00045 <span class="keywordflow">if</span> (encodedPointLen < 1 || !bt.<a class="code" href="class_buffered_transformation.html#9e1ad913c8fe697d269f408a7d5928fc" title="try to retrieve a single byte">Get</a>(type))<a name="l00046"></a>00046 <span class="keywordflow">return</span> <span class="keyword">false</span>;<a name="l00047"></a>00047 <a name="l00048"></a>00048 <span class="keywordflow">switch</span> (type)<a name="l00049"></a>00049 {<a name="l00050"></a>00050 <span class="keywordflow">case</span> 0:<a name="l00051"></a>00051 P.<a class="code" href="struct_e_c2_n_point.html#6ded60d603c7ba5af13c7ba3da253cf7">identity</a> = <span class="keyword">true</span>;<a name="l00052"></a>00052 <span class="keywordflow">return</span> <span class="keyword">true</span>;<a name="l00053"></a>00053 <span class="keywordflow">case</span> 2:<a name="l00054"></a>00054 <span class="keywordflow">case</span> 3:<a name="l00055"></a>00055 {<a name="l00056"></a>00056 <span class="keywordflow">if</span> (encodedPointLen != <a class="code" href="class_e_c2_n.html#c96cb02c86e4568d304cacc0b40783b3">EncodedPointSize</a>(<span class="keyword">true</span>))<a name="l00057"></a>00057 <span class="keywordflow">return</span> <span class="keyword">false</span>;<a name="l00058"></a>00058 <a name="l00059"></a>00059 P.<a class="code" href="struct_e_c2_n_point.html#6ded60d603c7ba5af13c7ba3da253cf7">identity</a> = <span class="keyword">false</span>;<a name="l00060"></a>00060 P.<a class="code" href="struct_e_c2_n_point.html#b90a3edb6b82f616b6a281315289c574">x</a>.<a class="code" href="class_polynomial_mod2.html#dc611fe09c3a9b919dce7b8b45cec29d">Decode</a>(bt, m_field->MaxElementByteLength()); <a name="l00061"></a>00061 <a name="l00062"></a>00062 <span class="keywordflow">if</span> (P.<a class="code" href="struct_e_c2_n_point.html#b90a3edb6b82f616b6a281315289c574">x</a>.<a class="code" href="class_polynomial_mod2.html#91d774c1b3a0b936317265dbf7e5ad75">IsZero</a>())<a name="l00063"></a>00063 {<a name="l00064"></a>00064 P.<a class="code" href="struct_e_c2_n_point.html#0ef74f2187b87841db0c36fef978f387">y</a> = m_field->SquareRoot(m_b);<a name="l00065"></a>00065 <span class="keywordflow">return</span> <span class="keyword">true</span>;<a name="l00066"></a>00066 }<a name="l00067"></a>00067 <a name="l00068"></a>00068 <a class="code" href="class_e_c2_n.html#e03206f65d1a99b107de72c7d86704c2">FieldElement</a> z = m_field->Square(P.<a class="code" href="struct_e_c2_n_point.html#b90a3edb6b82f616b6a281315289c574">x</a>);<a name="l00069"></a>00069 assert(P.<a class="code" href="struct_e_c2_n_point.html#b90a3edb6b82f616b6a281315289c574">x</a> == m_field->SquareRoot(z));<a name="l00070"></a>00070 P.<a class="code" href="struct_e_c2_n_point.html#0ef74f2187b87841db0c36fef978f387">y</a> = m_field->Divide(m_field->Add(m_field->Multiply(z, m_field->Add(P.<a class="code" href="struct_e_c2_n_point.html#b90a3edb6b82f616b6a281315289c574">x</a>, m_a)), m_b), z);<a name="l00071"></a>00071 assert(P.<a class="code" href="struct_e_c2_n_point.html#b90a3edb6b82f616b6a281315289c574">x</a> == m_field->Subtract(m_field->Divide(m_field->Subtract(m_field->Multiply(P.<a class="code" href="struct_e_c2_n_point.html#0ef74f2187b87841db0c36fef978f387">y</a>, z), m_b), z), m_a));<a name="l00072"></a>00072 z = m_field->SolveQuadraticEquation(P.<a class="code" href="struct_e_c2_n_point.html#0ef74f2187b87841db0c36fef978f387">y</a>);<a name="l00073"></a>00073 assert(m_field->Add(m_field->Square(z), z) == P.<a class="code" href="struct_e_c2_n_point.html#0ef74f2187b87841db0c36fef978f387">y</a>);<a name="l00074"></a>00074 z.SetCoefficient(0, type & 1);<a name="l00075"></a>00075 <a name="l00076"></a>00076 P.<a class="code" href="struct_e_c2_n_point.html#0ef74f2187b87841db0c36fef978f387">y</a> = m_field->Multiply(z, P.<a class="code" href="struct_e_c2_n_point.html#b90a3edb6b82f616b6a281315289c574">x</a>);<a name="l00077"></a>00077 <span class="keywordflow">return</span> <span class="keyword">true</span>;<a name="l00078"></a>00078 }<a name="l00079"></a>00079 <span class="keywordflow">case</span> 4:<a name="l00080"></a>00080 {<a name="l00081"></a>00081 <span class="keywordflow">if</span> (encodedPointLen != <a class="code" href="class_e_c2_n.html#c96cb02c86e4568d304cacc0b40783b3">EncodedPointSize</a>(<span class="keyword">false</span>))<a name="l00082"></a>00082 <span class="keywordflow">return</span> <span class="keyword">false</span>;<a name="l00083"></a>00083 <a name="l00084"></a>00084 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> len = m_field->MaxElementByteLength();⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -