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# ida.cpp

    00001 // ida.cpp - written and placed in the public domain by Wei Dai
    00002
    00003 #include "pch.h"
    00004 #include "ida.h"
    00005
    00006 #include "algebra.h"
    00007 #include "gf2_32.h"
    00008 #include "polynomi.h"
    00009 #include <functional>
    00010
    00011 #include "polynomi.cpp"
    00012
    00013 ANONYMOUS_NAMESPACE_BEGIN
    00014 static const CryptoPP::GF2_32 field;
    00015 NAMESPACE_END
    00016
    00017 using namespace std;
    00018
    00019 NAMESPACE_BEGIN(CryptoPP)
    00020
    00021 void RawIDA::IsolatedInitialize(const NameValuePairs &parameters)
    00022 {
    00023         if (!parameters.GetIntValue("RecoveryThreshold", m_threshold))
    00024                 throw InvalidArgument("RawIDA: missing RecoveryThreshold argument");
    00025
    00026         if (m_threshold <= 0)
    00027                 throw InvalidArgument("RawIDA: RecoveryThreshold must be greater than 0");
    00028
    00029         m_lastMapPosition = m_inputChannelMap.end();
    00030         m_channelsReady = 0;
    00031         m_channelsFinished = 0;
    00032         m_w.New(m_threshold);
    00033         m_y.New(m_threshold);
    00034         m_inputQueues.reserve(m_threshold);
    00035
    00036         m_outputChannelIds.clear();
    00037         m_outputChannelIdStrings.clear();
    00038         m_outputQueues.clear();
    00039
    00040         word32 outputChannelID;
    00041         if (parameters.GetValue("OutputChannelID", outputChannelID))
    00042                 AddOutputChannel(outputChannelID);
    00043         else
    00044         {
    00045                 int nShares = parameters.GetIntValueWithDefault("NumberOfShares", m_threshold);
    00046                 for (int i=0; i<nShares; i++)
    00047                         AddOutputChannel(i);
    00048         }
    00049 }
    00050
    00051 unsigned int RawIDA::InsertInputChannel(word32 channelId)
    00052 {
    00053         if (m_lastMapPosition != m_inputChannelMap.end())
    00054         {
    00055                 if (m_lastMapPosition->first == channelId)
    00056                         goto skipFind;
    00057                 ++m_lastMapPosition;
    00058                 if (m_lastMapPosition != m_inputChannelMap.end() && m_lastMapPosition->first == channelId)
    00059                         goto skipFind;
    00060         }
    00061         m_lastMapPosition = m_inputChannelMap.find(channelId);
    00062
    00063 skipFind:
    00064         if (m_lastMapPosition == m_inputChannelMap.end())
    00065         {
    00066                 if (m_inputChannelIds.size() == m_threshold)
    00067                         return m_threshold;
    00068
    00069                 m_lastMapPosition = m_inputChannelMap.insert(InputChannelMap::value_type(channelId, (unsigned int)m_inputChannelIds.size())).first;
    00070                 m_inputQueues.push_back(MessageQueue());
    00071                 m_inputChannelIds.push_back(channelId);
    00072
    00073                 if (m_inputChannelIds.size() == m_threshold)
    00074                         PrepareInterpolation();
    00075         }
    00076         return m_lastMapPosition->second;
    00077 }
    00078
    00079 unsigned int RawIDA::LookupInputChannel(word32 channelId) const
    00080 {
    00081         map<word32, unsigned int>::const_iterator it = m_inputChannelMap.find(channelId);
    00082         if (it == m_inputChannelMap.end())
    00083                 return m_threshold;
    00084         else
    00085                 return it->second;
    00086 }
    00087
    00088 void RawIDA::ChannelData(word32 channelId, const byte *inString, size_t length, bool messageEnd)
    00089 {
    00090         int i = InsertInputChannel(channelId);
    00091         if (i < m_threshold)
    00092         {
    00093                 lword size = m_inputQueues[i].MaxRetrievable();
    00094                 m_inputQueues[i].Put(inString, length);
    00095                 if (size < 4 && size + length >= 4)
    00096                 {
    00097                         m_channelsReady++;
    00098                         if (m_channelsReady == m_threshold)
    00099                                 ProcessInputQueues();
    00100                 }
    00101
    00102                 if (messageEnd)
    00103                 {
    00104                         m_inputQueues[i].MessageEnd();
    00105                         if (m_inputQueues[i].NumberOfMessages() == 1)
    00106                         {
    00107                                 m_channelsFinished++;
    00108                                 if (m_channelsFinished == m_threshold)
    00109                                 {
    00110                                         m_channelsReady = 0;
    00111                                         for (i=0; i<m_threshold; i++)
    00112                                                 m_channelsReady += m_inputQueues[i].AnyRetrievable();
    00113                                         ProcessInputQueues();
    00114                                 }
    00115                         }
    00116                 }
    00117         }
    00118 }
    00119
    00120 lword RawIDA::InputBuffered(word32 channelId) const
    00121 {
    00122         int i = LookupInputChannel(channelId);
    00123         return i < m_threshold ? m_inputQueues[i].MaxRetrievable() : 0;
    00124 }
    00125
    00126 void RawIDA::ComputeV(unsigned int i)
    00127 {
    00128         if (i >= m_v.size())
    00129         {
    00130                 m_v.resize(i+1);
    00131                 m_outputToInput.resize(i+1);
    00132         }
    00133
    00134         m_outputToInput[i] = LookupInputChannel(m_outputChannelIds[i]);
    00135         if (m_outputToInput[i] == m_threshold && i * m_threshold <= 1000*1000)
    00136         {
    00137                 m_v[i].resize(m_threshold);
    00138                 PrepareBulkPolynomialInterpolationAt(field, m_v[i].begin(), m_outputChannelIds[i], &(m_inputChannelIds[0]), m_w.begin(), m_threshold);
    00139         }
    00140 }
    00141
    00142 void RawIDA::AddOutputChannel(word32 channelId)
    00143 {
    00144         m_outputChannelIds.push_back(channelId);
    00145         m_outputChannelIdStrings.push_back(WordToString(channelId));
    00146         m_outputQueues.push_back(ByteQueue());
    00147         if (m_inputChannelIds.size() == m_threshold)
    00148                 ComputeV((unsigned int)m_outputChannelIds.size() - 1);
    00149 }
    00150
    00151 void RawIDA::PrepareInterpolation()
    00152 {
    00153         assert(m_inputChannelIds.size() == m_threshold);
    00154         PrepareBulkPolynomialInterpolation(field, m_w.begin(), &(m_inputChannelIds[0]), m_threshold);
    00155         for (unsigned int i=0; i<m_outputChannelIds.size(); i++)
    00156                 ComputeV(i);
    00157 }
    00158
    00159 void RawIDA::ProcessInputQueues()
    00160 {
    00161         bool finished = (m_channelsFinished == m_threshold);
    00162         int i;
    00163
    00164         while (finished ? m_channelsReady > 0 : m_channelsReady == m_threshold)
    00165         {
    00166                 m_channelsReady = 0;
    00167                 for (i=0; i<m_threshold; i++)
    00168                 {
    00169                         MessageQueue &queue = m_inputQueues[i];
    00170                         queue.GetWord32(m_y[i]);
    00171
    00172                         if (finished)
    00173                                 m_channelsReady += queue.AnyRetrievable();
    00174                         else
    00175                                 m_channelsReady += queue.NumberOfMessages() > 0 || queue.MaxRetrievable() >= 4;
    00176                 }
    00177
    00178                 for (i=0; (unsigned int)i<m_outputChannelIds.size(); i++)
    00179                 {
    00180                         if (m_outputToInput[i] != m_threshold)
    00181                                 m_outputQueues[i].PutWord32(m_y[m_outputToInput[i]]);
    00182                         else if (m_v[i].size() == m_threshold)
    00183                                 m_outputQueues[i].PutWord32(BulkPolynomialInterpolateAt(field, m_y.begin(), m_v[i].begin(), m_threshold));
    00184                         else
    00185                         {
    00186                                 m_u.resize(m_threshold);
    00187                                 PrepareBulkPolynomialInterpolationAt(field, m_u.begin(), m_outputChannelIds[i], &(m_inputChannelIds[0]), m_w.begin(), m_threshold);
    00188                                 m_outputQueues[i].PutWord32(BulkPolynomialInterpolateAt(field, m_y.begin(), m_u.begin(), m_threshold));
    00189                         }
    00190                 }
    00191         }
    00192
    00193         if (m_outputChannelIds.size() > 0 && m_outputQueues[0].AnyRetrievable())
    00194                 FlushOutputQueues();
    00195
    00196         if (finished)
    00197         {
    00198                 OutputMessageEnds();
    00199
    00200                 m_channelsReady = 0;
    00201                 m_channelsFinished = 0;
    00202                 m_v.clear();
    00203
    00204                 vector<MessageQueue> inputQueues;
    00205                 vector<word32> inputChannelIds;
    00206
    00207                 inputQueues.swap(m_inputQueues);
    00208                 inputChannelIds.swap(m_inputChannelIds);
    00209                 m_inputChannelMap.clear();
    00210                 m_lastMapPosition = m_inputChannelMap.end();
    00211
    00212                 for (i=0; i<m_threshold; i++)
    00213                 {
    00214                         inputQueues[i].GetNextMessage();
    00215                         inputQueues[i].TransferAllTo(*AttachedTransformation(), WordToString(inputChannelIds[i]));
    00216                 }
    00217         }
    00218 }
    00219
    00220 void RawIDA::FlushOutputQueues()
    00221 {
    00222         for (unsigned int i=0; i<m_outputChannelIds.size(); i++)
    00223                 m_outputQueues[i].TransferAllTo(*AttachedTransformation(), m_outputChannelIdStrings[i]);
    00224 }
    00225
    00226 void RawIDA::OutputMessageEnds()
    00227 {
    00228         if (GetAutoSignalPropagation() != 0)
    00229         {
    00230                 for (unsigned int i=0; i<m_outputChannelIds.size(); i++)
    00231                         AttachedTransformation()->ChannelMessageEnd(m_outputChannelIdStrings[i], GetAutoSignalPropagation()-1);
    00232         }
    00233 }
    00234
    00235 // ****************************************************************
    00236
    00237 void SecretSharing::IsolatedInitialize(const NameValuePairs &parameters)
    00238 {
    00239         m_pad = parameters.GetValueWithDefault("AddPadding", true);
    00240         m_ida.IsolatedInitialize(parameters);
    00241 }
    00242
    00243 size_t SecretSharing::Put2(const byte *begin, size_t length, int messageEnd, bool blocking)
    00244 {
    00245         if (!blocking)
    00246                 throw BlockingInputOnly("SecretSharing");
    00247
    00248         SecByteBlock buf(UnsignedMin(256, length));
    00249         unsigned int threshold = m_ida.GetThreshold();
    00250         while (length > 0)
    00251         {
    00252                 size_t len = STDMIN(length, buf.size());
    00253                 m_ida.ChannelData(0xffffffff, begin, len, false);
    00254                 for (unsigned int i=0; i<threshold-1; i++)
    00255                 {
    00256                         m_rng.GenerateBlock(buf, len);
    00257                         m_ida.ChannelData(i, buf, len, false);
    00258                 }
    00259                 length -= len;
    00260                 begin += len;
    00261         }
    00262
    00263         if (messageEnd)
    00264         {
    00265                 m_ida.SetAutoSignalPropagation(messageEnd-1);
    00266                 if (m_pad)
    00267                 {
    00268                         SecretSharing::Put(1);
    00269                         while (m_ida.InputBuffered(0xffffffff) > 0)
    00270                                 SecretSharing::Put(0);
    00271                 }
    00272                 m_ida.ChannelData(0xffffffff, NULL, 0, true);
    00273                 for (unsigned int i=0; i<m_ida.GetThreshold()-1; i++)
    00274                         m_ida.ChannelData(i, NULL, 0, true);
    00275         }
    00276
    00277         return 0;
    00278 }
    00279
    00280 void SecretRecovery::IsolatedInitialize(const NameValuePairs &parameters)
    00281 {
    00282         m_pad = parameters.GetValueWithDefault("RemovePadding", true);
    00283         RawIDA::IsolatedInitialize(CombinedNameValuePairs(parameters, MakeParameters("OutputChannelID", (word32)0xffffffff)));
    00284 }
    00285
    00286 void SecretRecovery::FlushOutputQueues()
    00287 {
    00288         if (m_pad)
    00289                 m_outputQueues[0].TransferTo(*AttachedTransformation(), m_outputQueues[0].MaxRetrievable()-4);
    00290         else
    00291                 m_outputQueues[0].TransferTo(*AttachedTransformation());
    00292 }
    00293
    00294 void SecretRecovery::OutputMessageEnds()
    00295 {
    00296         if (m_pad)
    00297         {
    00298                 PaddingRemover paddingRemover(new Redirector(*AttachedTransformation()));
    00299                 m_outputQueues[0].TransferAllTo(paddingRemover);
    00300         }
    00301
    00302         if (GetAutoSignalPropagation() != 0)
    00303                 AttachedTransformation()->MessageEnd(GetAutoSignalPropagation()-1);
    00304 }
    00305
    00306 // ****************************************************************
    00307
    00308 void InformationDispersal::IsolatedInitialize(const NameValuePairs &parameters)
    00309 {
    00310         m_nextChannel = 0;
    00311         m_pad = parameters.GetValueWithDefault("AddPadding", true);
    00312         m_ida.IsolatedInitialize(parameters);
    00313 }
    00314
    00315 size_t InformationDispersal::Put2(const byte *begin, size_t length, int messageEnd, bool blocking)
    00316 {
    00317         if (!blocking)
    00318                 throw BlockingInputOnly("InformationDispersal");
    00319
    00320         while (length--)
    00321         {
    00322                 m_ida.ChannelData(m_nextChannel, begin, 1, false);
    00323                 begin++;
    00324                 m_nextChannel++;
    00325                 if (m_nextChannel == m_ida.GetThreshold())
    00326                         m_nextChannel = 0;
    00327         }
    00328
    00329         if (messageEnd)
    00330         {
    00331                 m_ida.SetAutoSignalPropagation(messageEnd-1);
    00332                 if (m_pad)
    00333                         InformationDispersal::Put(1);
    00334                 for (word32 i=0; i<m_ida.GetThreshold(); i++)
    00335                         m_ida.ChannelData(i, NULL, 0, true);
    00336         }
    00337
    00338         return 0;
    00339 }
    00340
    00341 void InformationRecovery::IsolatedInitialize(const NameValuePairs &parameters)
    00342 {
    00343         m_pad = parameters.GetValueWithDefault("RemovePadding", true);
    00344         RawIDA::IsolatedInitialize(parameters);
    00345 }
    00346
    00347 void InformationRecovery::FlushOutputQueues()
    00348 {
    00349         while (m_outputQueues[0].AnyRetrievable())
    00350         {
    00351                 for (unsigned int i=0; i<m_outputChannelIds.size(); i++)
    00352                         m_outputQueues[i].TransferTo(m_queue, 1);
    00353         }
    00354
    00355         if (m_pad)
    00356                 m_queue.TransferTo(*AttachedTransformation(), m_queue.MaxRetrievable()-4*m_threshold);
    00357         else
    00358                 m_queue.TransferTo(*AttachedTransformation());
    00359 }
    00360
    00361 void InformationRecovery::OutputMessageEnds()
    00362 {
    00363         if (m_pad)
    00364         {
    00365                 PaddingRemover paddingRemover(new Redirector(*AttachedTransformation()));
    00366                 m_queue.TransferAllTo(paddingRemover);
    00367         }
    00368
    00369         if (GetAutoSignalPropagation() != 0)
    00370                 AttachedTransformation()->MessageEnd(GetAutoSignalPropagation()-1);
    00371 }
    00372
    00373 size_t PaddingRemover::Put2(const byte *begin, size_t length, int messageEnd, bool blocking)
    00374 {
    00375         if (!blocking)
    00376                 throw BlockingInputOnly("PaddingRemover");
    00377
    00378         const byte *const end = begin + length;
    00379
    00380         if (m_possiblePadding)
    00381         {
    00382                 size_t len = find_if(begin, end, bind2nd(not_equal_to<byte>(), 0)) - begin;
    00383                 m_zeroCount += len;
    00384                 begin += len;
    00385                 if (begin == end)
    00386                         return 0;
    00387
    00388                 AttachedTransformation()->Put(1);
    00389                 while (m_zeroCount--)
    00390                         AttachedTransformation()->Put(0);
    00391                 AttachedTransformation()->Put(*begin++);
    00392                 m_possiblePadding = false;
    00393         }
    00394
    00395 #if defined(_MSC_VER) && !defined(__MWERKS__) && (_MSC_VER <= 1300)
    00396         // VC60 and VC7 workaround: built-in reverse_iterator has two template parameters, Dinkumware only has one
    00397         typedef reverse_bidirectional_iterator<const byte *, const byte> RevIt;
    00398 #elif defined(_RWSTD_NO_CLASS_PARTIAL_SPEC)
    00399         typedef reverse_iterator<const byte *, random_access_iterator_tag, const byte> RevIt;
    00400 #else
    00401         typedef reverse_iterator<const byte *> RevIt;
    00402 #endif
    00403         const byte *x = find_if(RevIt(end), RevIt(begin), bind2nd(not_equal_to<byte>(), 0)).base();
    00404         if (x != begin && *(x-1) == 1)
    00405         {
    00406                 AttachedTransformation()->Put(begin, x-begin-1);
    00407                 m_possiblePadding = true;
    00408                 m_zeroCount = end - x;
    00409         }
    00410         else
    00411                 AttachedTransformation()->Put(begin, end-begin);
    00412
    00413         if (messageEnd)
    00414         {
    00415                 m_possiblePadding = false;
    00416                 Output(0, begin, length, messageEnd, blocking);
    00417         }
    00418         return 0;
    00419 }
    00420
    00421 NAMESPACE_END