esign.h

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00001 #ifndef CRYPTOPP_ESIGN_H
00002 #define CRYPTOPP_ESIGN_H
00003 
00004 /** \file
00005     This file contains classes that implement the
00006     ESIGN signature schemes as defined in IEEE P1363a.
00007 */
00008 
00009 #include "pubkey.h"
00010 #include "integer.h"
00011 #include "asn.h"
00012 
00013 NAMESPACE_BEGIN(CryptoPP)
00014 
00015 //! _
00016 class ESIGNFunction : public TrapdoorFunction, public ASN1CryptoMaterial<PublicKey>
00017 {
00018     typedef ESIGNFunction ThisClass;
00019 
00020 public:
00021     void Initialize(const Integer &n, const Integer &e)
00022         {m_n = n; m_e = e;}
00023 
00024     // PublicKey
00025     void BERDecode(BufferedTransformation &bt);
00026     void DEREncode(BufferedTransformation &bt) const;
00027 
00028     // CryptoMaterial
00029     bool Validate(RandomNumberGenerator &rng, unsigned int level) const;
00030     bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
00031     void AssignFrom(const NameValuePairs &source);
00032 
00033     // TrapdoorFunction
00034     Integer ApplyFunction(const Integer &x) const;
00035     Integer PreimageBound() const {return m_n;}
00036     Integer ImageBound() const {return Integer::Power2(GetK());}
00037 
00038     // non-derived
00039     const Integer & GetModulus() const {return m_n;}
00040     const Integer & GetPublicExponent() const {return m_e;}
00041 
00042     void SetModulus(const Integer &n) {m_n = n;}
00043     void SetPublicExponent(const Integer &e) {m_e = e;}
00044 
00045 protected:
00046     unsigned int GetK() const {return m_n.BitCount()/3-1;}
00047 
00048     Integer m_n, m_e;
00049 };
00050 
00051 //! _
00052 class InvertibleESIGNFunction : public ESIGNFunction, public RandomizedTrapdoorFunctionInverse, public PrivateKey
00053 {
00054     typedef InvertibleESIGNFunction ThisClass;
00055 
00056 public:
00057     void Initialize(const Integer &n, const Integer &e, const Integer &p, const Integer &q)
00058         {m_n = n; m_e = e; m_p = p; m_q = q;}
00059     // generate a random private key
00060     void Initialize(RandomNumberGenerator &rng, unsigned int modulusBits)
00061         {GenerateRandomWithKeySize(rng, modulusBits);}
00062 
00063     void BERDecode(BufferedTransformation &bt);
00064     void DEREncode(BufferedTransformation &bt) const;
00065 
00066     Integer CalculateRandomizedInverse(RandomNumberGenerator &rng, const Integer &x) const;
00067 
00068     // GeneratibleCryptoMaterial
00069     bool Validate(RandomNumberGenerator &rng, unsigned int level) const;
00070     bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
00071     void AssignFrom(const NameValuePairs &source);
00072     /*! parameters: (ModulusSize) */
00073     void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg);
00074 
00075     const Integer& GetPrime1() const {return m_p;}
00076     const Integer& GetPrime2() const {return m_q;}
00077 
00078     void SetPrime1(const Integer &p) {m_p = p;}
00079     void SetPrime2(const Integer &q) {m_q = q;}
00080 
00081 protected:
00082     Integer m_p, m_q;
00083 };
00084 
00085 //! _
00086 template <class T>
00087 class EMSA5Pad : public PK_DeterministicSignatureMessageEncodingMethod
00088 {
00089 public:
00090     static const char *StaticAlgorithmName() {return "EMSA5";}
00091     
00092     void ComputeMessageRepresentative(RandomNumberGenerator &rng, 
00093         const byte *recoverableMessage, size_t recoverableMessageLength,
00094         HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty,
00095         byte *representative, size_t representativeBitLength) const
00096     {
00097         SecByteBlock digest(hash.DigestSize());
00098         hash.Final(digest);
00099         size_t representativeByteLength = BitsToBytes(representativeBitLength);
00100         T mgf;
00101         mgf.GenerateAndMask(hash, representative, representativeByteLength, digest, digest.size(), false);
00102         if (representativeBitLength % 8 != 0)
00103             representative[0] = (byte)Crop(representative[0], representativeBitLength % 8);
00104     }
00105 };
00106 
00107 //! EMSA5, for use with ESIGN
00108 struct P1363_EMSA5 : public SignatureStandard
00109 {
00110     typedef EMSA5Pad<P1363_MGF1> SignatureMessageEncodingMethod;
00111 };
00112 
00113 struct ESIGN_Keys
00114 {
00115     static std::string StaticAlgorithmName() {return "ESIGN";}
00116     typedef ESIGNFunction PublicKey;
00117     typedef InvertibleESIGNFunction PrivateKey;
00118 };
00119 
00120 //! ESIGN, as defined in IEEE P1363a
00121 template <class H, class STANDARD = P1363_EMSA5>
00122 struct ESIGN : public TF_SS<STANDARD, H, ESIGN_Keys>
00123 {
00124 };
00125 
00126 NAMESPACE_END
00127 
00128 #endif

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