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# ida.h

    00001 #ifndef CRYPTOPP_IDA_H
    00002 #define CRYPTOPP_IDA_H
    00003
    00004 #include "mqueue.h"
    00005 #include "filters.h"
    00006 #include "channels.h"
    00007 #include <map>
    00008 #include <vector>
    00009
    00010 NAMESPACE_BEGIN(CryptoPP)
    00011
    00012 /// base class for secret sharing and information dispersal
    00013 class RawIDA : public AutoSignaling<Unflushable<Multichannel<Filter> > >
    00014 {
    00015 public:
    00016         RawIDA(BufferedTransformation *attachment=NULL)
    00017                 {Detach(attachment);}
    00018
    00019         unsigned int GetThreshold() const {return m_threshold;}
    00020         void AddOutputChannel(word32 channelId);
    00021         void ChannelData(word32 channelId, const byte *inString, size_t length, bool messageEnd);
    00022         lword InputBuffered(word32 channelId) const;
    00023
    00024         void IsolatedInitialize(const NameValuePairs &parameters=g_nullNameValuePairs);
    00025         size_t ChannelPut2(const std::string &channel, const byte *begin, size_t length, int messageEnd, bool blocking)
    00026         {
    00027                 if (!blocking)
    00028                         throw BlockingInputOnly("RawIDA");
    00029                 ChannelData(StringToWord<word32>(channel), begin, length, messageEnd != 0);
    00030                 return 0;
    00031         }
    00032
    00033 protected:
    00034         virtual void FlushOutputQueues();
    00035         virtual void OutputMessageEnds();
    00036
    00037         unsigned int InsertInputChannel(word32 channelId);
    00038         unsigned int LookupInputChannel(word32 channelId) const;
    00039         void ComputeV(unsigned int);
    00040         void PrepareInterpolation();
    00041         void ProcessInputQueues();
    00042
    00043         typedef std::map<word32, unsigned int> InputChannelMap;
    00044         InputChannelMap m_inputChannelMap;
    00045         InputChannelMap::iterator m_lastMapPosition;
    00046         std::vector<MessageQueue> m_inputQueues;
    00047         std::vector<word32> m_inputChannelIds, m_outputChannelIds, m_outputToInput;
    00048         std::vector<std::string> m_outputChannelIdStrings;
    00049         std::vector<ByteQueue> m_outputQueues;
    00050         int m_threshold;
    00051         unsigned int m_channelsReady, m_channelsFinished;
    00052         std::vector<SecBlock<word32> > m_v;
    00053         SecBlock<word32> m_u, m_w, m_y;
    00054 };
    00055
    00056 /// a variant of Shamir's Secret Sharing Algorithm
    00057 class SecretSharing : public CustomFlushPropagation<Filter>
    00058 {
    00059 public:
    00060         SecretSharing(RandomNumberGenerator &rng, int threshold, int nShares, BufferedTransformation *attachment=NULL, bool addPadding=true)
    00061                 : m_rng(rng), m_ida(new OutputProxy(*this, true))
    00062         {
    00063                 Detach(attachment);
    00064                 IsolatedInitialize(MakeParameters("RecoveryThreshold", threshold)("NumberOfShares", nShares)("AddPadding", addPadding));
    00065         }
    00066
    00067         void IsolatedInitialize(const NameValuePairs &parameters=g_nullNameValuePairs);
    00068         size_t Put2(const byte *begin, size_t length, int messageEnd, bool blocking);
    00069         bool Flush(bool hardFlush, int propagation=-1, bool blocking=true) {return m_ida.Flush(hardFlush, propagation, blocking);}
    00070
    00071 protected:
    00072         RandomNumberGenerator &m_rng;
    00073         RawIDA m_ida;
    00074         bool m_pad;
    00075 };
    00076
    00077 /// a variant of Shamir's Secret Sharing Algorithm
    00078 class SecretRecovery : public RawIDA
    00079 {
    00080 public:
    00081         SecretRecovery(int threshold, BufferedTransformation *attachment=NULL, bool removePadding=true)
    00082                 : RawIDA(attachment)
    00083                 {IsolatedInitialize(MakeParameters("RecoveryThreshold", threshold)("RemovePadding", removePadding));}
    00084
    00085         void IsolatedInitialize(const NameValuePairs &parameters=g_nullNameValuePairs);
    00086
    00087 protected:
    00088         void FlushOutputQueues();
    00089         void OutputMessageEnds();
    00090
    00091         bool m_pad;
    00092 };
    00093
    00094 /// a variant of Rabin's Information Dispersal Algorithm
    00095 class InformationDispersal : public CustomFlushPropagation<Filter>
    00096 {
    00097 public:
    00098         InformationDispersal(int threshold, int nShares, BufferedTransformation *attachment=NULL, bool addPadding=true)
    00099                 : m_ida(new OutputProxy(*this, true))
    00100         {
    00101                 Detach(attachment);
    00102                 IsolatedInitialize(MakeParameters("RecoveryThreshold", threshold)("NumberOfShares", nShares)("AddPadding", addPadding));
    00103         }
    00104
    00105         void IsolatedInitialize(const NameValuePairs &parameters=g_nullNameValuePairs);
    00106         size_t Put2(const byte *begin, size_t length, int messageEnd, bool blocking);
    00107         bool Flush(bool hardFlush, int propagation=-1, bool blocking=true) {return m_ida.Flush(hardFlush, propagation, blocking);}
    00108
    00109 protected:
    00110         RawIDA m_ida;
    00111         bool m_pad;
    00112         unsigned int m_nextChannel;
    00113 };
    00114
    00115 /// a variant of Rabin's Information Dispersal Algorithm
    00116 class InformationRecovery : public RawIDA
    00117 {
    00118 public:
    00119         InformationRecovery(int threshold, BufferedTransformation *attachment=NULL, bool removePadding=true)
    00120                 : RawIDA(attachment)
    00121                 {IsolatedInitialize(MakeParameters("RecoveryThreshold", threshold)("RemovePadding", removePadding));}
    00122
    00123         void IsolatedInitialize(const NameValuePairs &parameters=g_nullNameValuePairs);
    00124
    00125 protected:
    00126         void FlushOutputQueues();
    00127         void OutputMessageEnds();
    00128
    00129         bool m_pad;
    00130         ByteQueue m_queue;
    00131 };
    00132
    00133 class PaddingRemover : public Unflushable<Filter>
    00134 {
    00135 public:
    00136         PaddingRemover(BufferedTransformation *attachment=NULL)
    00137                 : m_possiblePadding(false) {Detach(attachment);}
    00138
    00139         void IsolatedInitialize(const NameValuePairs &parameters) {m_possiblePadding = false;}
    00140         size_t Put2(const byte *begin, size_t length, int messageEnd, bool blocking);
    00141
    00142         // GetPossiblePadding() == false at the end of a message indicates incorrect padding
    00143         bool GetPossiblePadding() const {return m_possiblePadding;}
    00144
    00145 private:
    00146         bool m_possiblePadding;
    00147         lword m_zeroCount;
    00148 };
    00149
    00150 NAMESPACE_END
    00151
    00152 #endif