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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++: strciphr.h 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>strciphr.h</h1><a href="strciphr_8h.html">Go to the documentation of this file.</a><div class="fragment"><pre>00001 <span class="comment">/*! \file</span>00002 <span class="comment"> This file contains helper classes for implementing stream ciphers.</span>00003 <span class="comment"></span>00004 <span class="comment"> All this infrastructure may look very complex compared to what's in Crypto++ 4.x,</span>00005 <span class="comment"> but stream ciphers implementations now support a lot of new functionality,</span>00006 <span class="comment"> including better performance (minimizing copying), resetting of keys and IVs, and methods to</span>00007 <span class="comment"> query which features are supported by a cipher.</span>00008 <span class="comment"></span>00009 <span class="comment"> Here's an explanation of these classes. The word "policy" is used here to mean a class with a</span>00010 <span class="comment"> set of methods that must be implemented by individual stream cipher implementations.</span>00011 <span class="comment"> This is usually much simpler than the full stream cipher API, which is implemented by</span>00012 <span class="comment"> either AdditiveCipherTemplate or CFB_CipherTemplate using the policy. So for example, an</span>00013 <span class="comment"> implementation of SEAL only needs to implement the AdditiveCipherAbstractPolicy interface</span>00014 <span class="comment"> (since it's an additive cipher, i.e., it xors a keystream into the plaintext).</span>00015 <span class="comment"> See this line in seal.h:</span>00016 <span class="comment"></span>00017 <span class="comment"> typedef SymmetricCipherFinalTemplate<ConcretePolicyHolder<SEAL_Policy<B>, AdditiveCipherTemplate<> > > Encryption;</span>00018 <span class="comment"></span>00019 <span class="comment"> AdditiveCipherTemplate and CFB_CipherTemplate are designed so that they don't need</span>00020 <span class="comment"> to take a policy class as a template parameter (although this is allowed), so that</span>00021 <span class="comment"> their code is not duplicated for each new cipher. Instead they each</span>00022 <span class="comment"> get a reference to an abstract policy interface by calling AccessPolicy() on itself, so</span>00023 <span class="comment"> AccessPolicy() must be overriden to return the actual policy reference. This is done</span>00024 <span class="comment"> by the ConceretePolicyHolder class. Finally, SymmetricCipherFinalTemplate implements the constructors and</span>00025 <span class="comment"> other functions that must be implemented by the most derived class.</span>00026 <span class="comment">*/</span>00027 00028 <span class="preprocessor">#ifndef CRYPTOPP_STRCIPHR_H</span>00029 <span class="preprocessor"></span><span class="preprocessor">#define CRYPTOPP_STRCIPHR_H</span>00030 <span class="preprocessor"></span>00031 <span class="preprocessor">#include "seckey.h"</span>00032 <span class="preprocessor">#include "secblock.h"</span>00033 00034 NAMESPACE_BEGIN(CryptoPP)00035 00036 <span class="keyword">template</span> <<span class="keyword">class</span> POLICY_INTERFACE, <span class="keyword">class</span> BASE = Empty>00037 <span class="keyword">class </span>AbstractPolicyHolder : <span class="keyword">public</span> BASE00038 {00039 <span class="keyword">public</span>:00040 <span class="keyword">typedef</span> POLICY_INTERFACE PolicyInterface;00041 00042 <span class="keyword">protected</span>:00043 <span class="keyword">virtual</span> <span class="keyword">const</span> POLICY_INTERFACE & GetPolicy() <span class="keyword">const</span> =0;00044 <span class="keyword">virtual</span> POLICY_INTERFACE & AccessPolicy() =0;00045 };00046 00047 <span class="keyword">template</span> <<span class="keyword">class</span> POLICY, <span class="keyword">class</span> BASE, <span class="keyword">class</span> POLICY_INTERFACE = CPP_TYPENAME BASE::PolicyInterface>00048 <span class="keyword">class </span>ConcretePolicyHolder : <span class="keyword">public</span> BASE, <span class="keyword">protected</span> POLICY00049 {00050 <span class="keyword">protected</span>:00051 <span class="keyword">const</span> POLICY_INTERFACE & GetPolicy()<span class="keyword"> const </span>{<span class="keywordflow">return</span> *<span class="keyword">this</span>;}00052 POLICY_INTERFACE & AccessPolicy() {<span class="keywordflow">return</span> *<span class="keyword">this</span>;}00053 };00054 00055 <span class="keyword">enum</span> KeystreamOperation {WRITE_KEYSTREAM, XOR_KEYSTREAM, XOR_KEYSTREAM_INPLACE};00056 00057 <span class="keyword">struct </span>CRYPTOPP_DLL AdditiveCipherAbstractPolicy00058 {00059 <span class="keyword">virtual</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> GetAlignment() <span class="keyword">const</span> =0;00060 <span class="keyword">virtual</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> GetBytesPerIteration() <span class="keyword">const</span> =0;00061 <span class="keyword">virtual</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> GetIterationsToBuffer() <span class="keyword">const</span> =0;00062 <span class="keyword">virtual</span> <span class="keywordtype">void</span> WriteKeystream(byte *keystreamBuffer, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> iterationCount) =0;00063 <span class="keyword">virtual</span> <span class="keywordtype">bool</span> CanOperateKeystream()<span class="keyword"> const </span>{<span class="keywordflow">return</span> <span class="keyword">false</span>;}00064 <span class="keyword">virtual</span> <span class="keywordtype">void</span> OperateKeystream(KeystreamOperation operation, byte *output, <span class="keyword">const</span> byte *input, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> iterationCount) {assert(<span class="keyword">false</span>);}00065 <span class="keyword">virtual</span> <span class="keywordtype">void</span> CipherSetKey(<span class="keyword">const</span> <a class="code" href="class_name_value_pairs.html">NameValuePairs</a> &params, <span class="keyword">const</span> byte *key, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> length) =0;00066 <span class="keyword">virtual</span> <span class="keywordtype">void</span> CipherResynchronize(byte *keystreamBuffer, <span class="keyword">const</span> byte *iv) {<span class="keywordflow">throw</span> <a class="code" href="class_not_implemented.html">NotImplemented</a>(<span class="stringliteral">"StreamTransformation: this object doesn't support resynchronization"</span>);}00067 <span class="keyword">virtual</span> <span class="keywordtype">bool</span> IsRandomAccess() <span class="keyword">const</span> =0;00068 <span class="keyword">virtual</span> <span class="keywordtype">void</span> SeekToIteration(dword iterationCount) {assert(!IsRandomAccess()); <span class="keywordflow">throw</span> <a class="code" href="class_not_implemented.html">NotImplemented</a>(<span class="stringliteral">"StreamTransformation: this object doesn't support random access"</span>);}00069 };00070 00071 <span class="keyword">template</span> <<span class="keyword">typename</span> WT, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> W, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> X = 1, <span class="keyword">class</span> BASE = AdditiveCipherAbstractPolicy>00072 <span class="keyword">struct </span>AdditiveCipherConcretePolicy : <span class="keyword">public</span> BASE00073 {00074 <span class="keyword">typedef</span> WT WordType;00075 00076 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> GetAlignment()<span class="keyword"> const </span>{<span class="keywordflow">return</span> <span class="keyword">sizeof</span>(WordType);}00077 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> GetBytesPerIteration()<span class="keyword"> const </span>{<span class="keywordflow">return</span> <span class="keyword">sizeof</span>(WordType) * W;}00078 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> GetIterationsToBuffer()<span class="keyword"> const </span>{<span class="keywordflow">return</span> X;}00079 <span class="keywordtype">void</span> WriteKeystream(byte *buffer, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> iterationCount)00080 {OperateKeystream(WRITE_KEYSTREAM, buffer, NULL, iterationCount);}00081 <span class="keywordtype">bool</span> CanOperateKeystream()<span class="keyword"> const </span>{<span class="keywordflow">return</span> <span class="keyword">true</span>;}00082 <span class="keyword">virtual</span> <span class="keywordtype">void</span> OperateKeystream(KeystreamOperation operation, byte *output, <span class="keyword">const</span> byte *input, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> iterationCount) =0;00083 00084 <span class="keyword">template</span> <<span class="keyword">class</span> B>00085 <span class="keyword">struct </span>KeystreamOutput00086 {00087 KeystreamOutput(KeystreamOperation operation, byte *output, <span class="keyword">const</span> byte *input)00088 : m_operation(operation), m_output(output), m_input(input) {}00089 00090 <span class="keyword">inline</span> KeystreamOutput & operator()(WordType keystreamWord)00091 {00092 assert(IsAligned<WordType>(m_input));00093 assert(IsAligned<WordType>(m_output));00094 00095 <span class="keywordflow">if</span> (!NativeByteOrderIs(B::ToEnum()))00096 keystreamWord = ByteReverse(keystreamWord);00097 00098 <span class="keywordflow">if</span> (m_operation == WRITE_KEYSTREAM)00099 *(WordType*)m_output = keystreamWord;00100 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (m_operation == XOR_KEYSTREAM)00101 {00102 *(WordType*)m_output = keystreamWord ^ *(WordType*)m_input;00103 m_input += <span class="keyword">sizeof</span>(WordType);00104 }00105 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (m_operation == XOR_KEYSTREAM_INPLACE)00106 *(WordType*)m_output ^= keystreamWord;00107 00108 m_output += <span class="keyword">sizeof</span>(WordType);00109 00110 <span class="keywordflow">return</span> *<span class="keyword">this</span>;00111 }00112 00113 KeystreamOperation m_operation;00114 byte *m_output;00115 <span class="keyword">const</span> byte *m_input;00116 };00117 };00118 00119 <span class="keyword">template</span> <<span class="keyword">class</span> BASE = AbstractPolicyHolder<AdditiveCipherAbstractPolicy, TwoBases<SymmetricCipher, RandomNumberGenerator> > >00120 <span class="keyword">class </span>AdditiveCipherTemplate : <span class="keyword">public</span> BASE00121 {00122 <span class="keyword">public</span>:00123 byte GenerateByte();00124 <span class="keywordtype">void</span> ProcessData(byte *outString, <span class="keyword">const</span> byte *inString, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> length);00125 <span class="keywordtype">void</span> Resynchronize(<span class="keyword">const</span> byte *iv);00126 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> OptimalBlockSize()<span class="keyword"> const </span>{<span class="keywordflow">return</span> GetPolicy().GetBytesPerIteration();}00127 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> GetOptimalNextBlockSize()<span class="keyword"> const </span>{<span class="keywordflow">return</span> m_leftOver;}00128 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> OptimalDataAlignment()<span class="keyword"> const </span>{<span class="keywordflow">return</span> GetPolicy().GetAlignment();}00129 <span class="keywordtype">bool</span> IsSelfInverting()<span class="keyword"> const </span>{<span class="keywordflow">return</span> <span class="keyword">true</span>;}00130 <span class="keywordtype">bool</span> IsForwardTransformation()<span class="keyword"> const </span>{<span class="keywordflow">return</span> <span class="keyword">true</span>;}00131 <span class="keywordtype">bool</span> IsRandomAccess()<span class="keyword"> const </span>{<span class="keywordflow">return</span> GetPolicy().IsRandomAccess();}00132 <span class="keywordtype">void</span> Seek(dword position);00133 00134 <span class="keyword">typedef</span> <span class="keyword">typename</span> BASE::PolicyInterface PolicyInterface;00135 00136 <span class="keyword">protected</span>:00137 <span class="keywordtype">void</span> UncheckedSetKey(<span class="keyword">const</span> <a class="code" href="class_name_value_pairs.html">NameValuePairs</a> &params, <span class="keyword">const</span> byte *key, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> length);00138 00139 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> GetBufferByteSize(<span class="keyword">const</span> PolicyInterface &policy)<span class="keyword"> const </span>{<span class="keywordflow">return</span> policy.GetBytesPerIteration() * policy.GetIterationsToBuffer();}00140 00141 <span class="keyword">inline</span> byte * KeystreamBufferBegin() {<span class="keywordflow">return</span> m_buffer.data();}00142 <span class="keyword">inline</span> byte * KeystreamBufferEnd() {<span class="keywordflow">return</span> (m_buffer.data() + m_buffer.size());}00143 00144 <a class="code" href="class_sec_block.html">SecByteBlock</a> m_buffer;00145 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> m_leftOver;00146 };00147 00148 CRYPTOPP_DLL_TEMPLATE_CLASS TwoBases<SymmetricCipher, RandomNumberGenerator>;00149 CRYPTOPP_DLL_TEMPLATE_CLASS AbstractPolicyHolder<AdditiveCipherAbstractPolicy, TwoBases<SymmetricCipher, RandomNumberGenerator> >;⌨️ 快捷键说明
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