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Crypto++是一个非常强大的密码学库,主要是功能全

00130 {
00131 }
00132 
00133 DefaultDecryptor::DefaultDecryptor(<span class="keyword">const</span> byte *passphrase, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> passphraseLength, <a class="code" href="class_buffered_transformation.html">BufferedTransformation</a> *attachment, <span class="keywordtype">bool</span> throwException)
00134         : <a class="code" href="class_proxy_filter.html">ProxyFilter</a>(NULL, SALTLENGTH+BLOCKSIZE, 0, attachment)
00135         , m_state(WAITING_FOR_KEYCHECK)
00136         , m_passphrase(passphrase, passphraseLength)
00137         , m_throwException(throwException)
00138 {
00139 }
00140 
00141 <span class="keywordtype">void</span> DefaultDecryptor::FirstPut(<span class="keyword">const</span> byte *inString)
00142 {
00143         CheckKey(inString, inString+SALTLENGTH);
00144 }
00145 
00146 <span class="keywordtype">void</span> DefaultDecryptor::LastPut(<span class="keyword">const</span> byte *inString, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> length)
00147 {
00148         <span class="keywordflow">if</span> (m_filter.get() == NULL)
00149         {
00150                 m_state = KEY_BAD;
00151                 <span class="keywordflow">if</span> (m_throwException)
00152                         <span class="keywordflow">throw</span> KeyBadErr();
00153         }
00154         <span class="keywordflow">else</span>
00155         {
00156                 m_filter-&gt;MessageEnd();
00157                 m_state = WAITING_FOR_KEYCHECK;
00158         }
00159 }
00160 
00161 <span class="keywordtype">void</span> DefaultDecryptor::CheckKey(<span class="keyword">const</span> byte *salt, <span class="keyword">const</span> byte *keyCheck)
00162 {
00163         <a class="code" href="class_sec_block.html">SecByteBlock</a> check(STDMAX((<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>)2*BLOCKSIZE, (<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>)DefaultHashModule::DIGESTSIZE));
00164 
00165         <a class="code" href="class_s_h_a.html">DefaultHashModule</a> hash;
00166         hash.Update(m_passphrase, m_passphrase.<a class="code" href="class_sec_block.html#_sec_block_with_hinta13">size</a>());
00167         hash.Update(salt, SALTLENGTH);
00168         hash.<a class="code" href="class_hash_transformation.html#_x_m_a_c_c___basea13">Final</a>(check);
00169 
00170         <a class="code" href="class_sec_block.html">SecByteBlock</a> key(KEYLENGTH);
00171         <a class="code" href="class_sec_block.html">SecByteBlock</a> <a class="code" href="namespace_name.html#a4">IV</a>(BLOCKSIZE);
00172         GenerateKeyIV(m_passphrase, m_passphrase.<a class="code" href="class_sec_block.html#_sec_block_with_hinta13">size</a>(), salt, SALTLENGTH, key, <a class="code" href="namespace_name.html#a4">IV</a>);
00173 
00174         m_cipher.SetKeyWithIV(key, key.size(), <a class="code" href="namespace_name.html#a4">IV</a>);
00175         std::auto_ptr&lt;StreamTransformationFilter&gt; decryptor(<span class="keyword">new</span> <a class="code" href="class_stream_transformation_filter.html">StreamTransformationFilter</a>(m_cipher));
00176 
00177         decryptor-&gt;Put(keyCheck, BLOCKSIZE);
00178         decryptor-&gt;ForceNextPut();
00179         decryptor-&gt;Get(check+BLOCKSIZE, BLOCKSIZE);
00180 
00181         SetFilter(decryptor.release());
00182 
00183         <span class="keywordflow">if</span> (memcmp(check, check+BLOCKSIZE, BLOCKSIZE))
00184         {
00185                 m_state = KEY_BAD;
00186                 <span class="keywordflow">if</span> (m_throwException)
00187                         <span class="keywordflow">throw</span> KeyBadErr();
00188         }
00189         <span class="keywordflow">else</span>
00190                 m_state = KEY_GOOD;
00191 }
00192 
00193 <span class="comment">// ********************************************************</span>
00194 
00195 <span class="keyword">static</span> <a class="code" href="class_h_m_a_c.html">DefaultMAC</a> * NewDefaultEncryptorMAC(<span class="keyword">const</span> byte *passphrase, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> passphraseLength)
00196 {
00197         <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> macKeyLength = DefaultMAC::StaticGetValidKeyLength(16);
00198         <a class="code" href="class_sec_block.html">SecByteBlock</a> macKey(macKeyLength);
00199         <span class="comment">// since the MAC is encrypted there is no reason to mash the passphrase for many iterations</span>
00200         Mash(passphrase, passphraseLength, macKey, macKeyLength, 1);
00201         <span class="keywordflow">return</span> <span class="keyword">new</span> <a class="code" href="class_h_m_a_c.html">DefaultMAC</a>(macKey, macKeyLength);
00202 }
00203 
00204 DefaultEncryptorWithMAC::DefaultEncryptorWithMAC(<span class="keyword">const</span> <span class="keywordtype">char</span> *passphrase, <a class="code" href="class_buffered_transformation.html">BufferedTransformation</a> *attachment)
00205         : <a class="code" href="class_proxy_filter.html">ProxyFilter</a>(NULL, 0, 0, attachment)
00206         , m_mac(NewDefaultEncryptorMAC((const byte *)passphrase, strlen(passphrase)))
00207 {
00208         SetFilter(<span class="keyword">new</span> <a class="code" href="class_hash_filter.html">HashFilter</a>(*m_mac, <span class="keyword">new</span> <a class="code" href="class_default_encryptor.html">DefaultEncryptor</a>(passphrase), <span class="keyword">true</span>));
00209 }
00210 
00211 DefaultEncryptorWithMAC::DefaultEncryptorWithMAC(<span class="keyword">const</span> byte *passphrase, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> passphraseLength, <a class="code" href="class_buffered_transformation.html">BufferedTransformation</a> *attachment)
00212         : <a class="code" href="class_proxy_filter.html">ProxyFilter</a>(NULL, 0, 0, attachment)
00213         , m_mac(NewDefaultEncryptorMAC(passphrase, passphraseLength))
00214 {
00215         SetFilter(<span class="keyword">new</span> <a class="code" href="class_hash_filter.html">HashFilter</a>(*m_mac, <span class="keyword">new</span> <a class="code" href="class_default_encryptor.html">DefaultEncryptor</a>(passphrase, passphraseLength), <span class="keyword">true</span>));
00216 }
00217 
00218 <span class="keywordtype">void</span> DefaultEncryptorWithMAC::LastPut(<span class="keyword">const</span> byte *inString, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> length)
00219 {
00220         m_filter-&gt;MessageEnd();
00221 }
00222 
00223 <span class="comment">// ********************************************************</span>
00224 
00225 DefaultDecryptorWithMAC::DefaultDecryptorWithMAC(<span class="keyword">const</span> <span class="keywordtype">char</span> *passphrase, <a class="code" href="class_buffered_transformation.html">BufferedTransformation</a> *attachment, <span class="keywordtype">bool</span> throwException)
00226         : <a class="code" href="class_proxy_filter.html">ProxyFilter</a>(NULL, 0, 0, attachment)
00227         , m_mac(NewDefaultEncryptorMAC((const byte *)passphrase, strlen(passphrase)))
00228         , m_throwException(throwException)
00229 {
00230         SetFilter(<span class="keyword">new</span> <a class="code" href="class_default_decryptor.html">DefaultDecryptor</a>(passphrase, m_hashVerifier=<span class="keyword">new</span> <a class="code" href="class_hash_verification_filter.html">HashVerifier</a>(*m_mac, NULL, HashVerifier::PUT_MESSAGE), throwException));
00231 }
00232 
00233 DefaultDecryptorWithMAC::DefaultDecryptorWithMAC(<span class="keyword">const</span> byte *passphrase, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> passphraseLength, <a class="code" href="class_buffered_transformation.html">BufferedTransformation</a> *attachment, <span class="keywordtype">bool</span> throwException)
00234         : <a class="code" href="class_proxy_filter.html">ProxyFilter</a>(NULL, 0, 0, attachment)
00235         , m_mac(NewDefaultEncryptorMAC(passphrase, passphraseLength))
00236         , m_throwException(throwException)
00237 {
00238         SetFilter(<span class="keyword">new</span> <a class="code" href="class_default_decryptor.html">DefaultDecryptor</a>(passphrase, passphraseLength, m_hashVerifier=<span class="keyword">new</span> <a class="code" href="class_hash_verification_filter.html">HashVerifier</a>(*m_mac, NULL, HashVerifier::PUT_MESSAGE), throwException));
00239 }
00240 
00241 DefaultDecryptor::State DefaultDecryptorWithMAC::CurrentState()<span class="keyword"> const</span>
00242 <span class="keyword"></span>{
00243         <span class="keywordflow">return</span> static_cast&lt;const DefaultDecryptor *&gt;(m_filter.get())-&gt;CurrentState();
00244 }
00245 
00246 <span class="keywordtype">bool</span> DefaultDecryptorWithMAC::CheckLastMAC()<span class="keyword"> const</span>
00247 <span class="keyword"></span>{
00248         <span class="keywordflow">return</span> m_hashVerifier-&gt;<a class="code" href="class_hash_verification_filter.html#_hash_verification_filtera1">GetLastResult</a>();
00249 }
00250 
00251 <span class="keywordtype">void</span> DefaultDecryptorWithMAC::LastPut(<span class="keyword">const</span> byte *inString, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> length)
00252 {
00253         m_filter-&gt;MessageEnd();
00254         <span class="keywordflow">if</span> (m_throwException &amp;&amp; !CheckLastMAC())
00255                 <span class="keywordflow">throw</span> MACBadErr();
00256 }
00257 
00258 NAMESPACE_END
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