// esign.h - originally written and placed in the public domain by Wei Dai //! \file esign.h //! \brief Classes providing ESIGN signature schemes as defined in IEEE P1363a //! \since Crypto++ 5.0 #ifndef CRYPTOPP_ESIGN_H #define CRYPTOPP_ESIGN_H #include "cryptlib.h" #include "pubkey.h" #include "integer.h" #include "asn.h" #include "misc.h" NAMESPACE_BEGIN(CryptoPP) //! \class ESIGNFunction //! \brief ESIGN trapdoor function using the public key //! \since Crypto++ 5.0 class ESIGNFunction : public TrapdoorFunction, public ASN1CryptoMaterial { typedef ESIGNFunction ThisClass; public: //! \brief Initialize a ESIGN public key with {n,e} //! \param n the modulus //! \param e the public exponent void Initialize(const Integer &n, const Integer &e) {m_n = n; m_e = e;} // PublicKey void BERDecode(BufferedTransformation &bt); void DEREncode(BufferedTransformation &bt) const; // CryptoMaterial bool Validate(RandomNumberGenerator &rng, unsigned int level) const; bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const; void AssignFrom(const NameValuePairs &source); // TrapdoorFunction Integer ApplyFunction(const Integer &x) const; Integer PreimageBound() const {return m_n;} Integer ImageBound() const {return Integer::Power2(GetK());} // non-derived const Integer & GetModulus() const {return m_n;} const Integer & GetPublicExponent() const {return m_e;} void SetModulus(const Integer &n) {m_n = n;} void SetPublicExponent(const Integer &e) {m_e = e;} protected: // Covertiy finding on overflow. The library allows small values for research purposes. unsigned int GetK() const {return SaturatingSubtract(m_n.BitCount()/3, 1U);} Integer m_n, m_e; }; //! \class InvertibleESIGNFunction //! \brief ESIGN trapdoor function using the private key //! \since Crypto++ 5.0 class InvertibleESIGNFunction : public ESIGNFunction, public RandomizedTrapdoorFunctionInverse, public PrivateKey { typedef InvertibleESIGNFunction ThisClass; public: //! \brief Initialize a ESIGN private key with {n,e,p,q} //! \param n modulus //! \param e public exponent //! \param p first prime factor //! \param q second prime factor //! \details This Initialize() function overload initializes a private key from existing parameters. void Initialize(const Integer &n, const Integer &e, const Integer &p, const Integer &q) {m_n = n; m_e = e; m_p = p; m_q = q;} //! \brief Create a ESIGN private key //! \param rng a RandomNumberGenerator derived class //! \param modulusBits the size of the modulud, in bits //! \details This function overload of Initialize() creates a new private key because it //! takes a RandomNumberGenerator() as a parameter. If you have an existing keypair, //! then use one of the other Initialize() overloads. void Initialize(RandomNumberGenerator &rng, unsigned int modulusBits) {GenerateRandomWithKeySize(rng, modulusBits);} // Squash Visual Studio C4250 warning void Save(BufferedTransformation &bt) const {BEREncode(bt);} // Squash Visual Studio C4250 warning void Load(BufferedTransformation &bt) {BERDecode(bt);} void BERDecode(BufferedTransformation &bt); void DEREncode(BufferedTransformation &bt) const; Integer CalculateRandomizedInverse(RandomNumberGenerator &rng, const Integer &x) const; // GeneratibleCryptoMaterial bool Validate(RandomNumberGenerator &rng, unsigned int level) const; bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const; void AssignFrom(const NameValuePairs &source); /*! parameters: (ModulusSize) */ void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg); const Integer& GetPrime1() const {return m_p;} const Integer& GetPrime2() const {return m_q;} void SetPrime1(const Integer &p) {m_p = p;} void SetPrime2(const Integer &q) {m_q = q;} protected: Integer m_p, m_q; }; //! \class EMSA5Pad //! \brief EMSA5 padding method //! \tparam T Mask Generation Function //! \since Crypto++ 5.0 template class EMSA5Pad : public PK_DeterministicSignatureMessageEncodingMethod { public: CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "EMSA5";} void ComputeMessageRepresentative(RandomNumberGenerator &rng, const byte *recoverableMessage, size_t recoverableMessageLength, HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty, byte *representative, size_t representativeBitLength) const { CRYPTOPP_UNUSED(rng), CRYPTOPP_UNUSED(recoverableMessage), CRYPTOPP_UNUSED(recoverableMessageLength); CRYPTOPP_UNUSED(messageEmpty), CRYPTOPP_UNUSED(hashIdentifier); SecByteBlock digest(hash.DigestSize()); hash.Final(digest); size_t representativeByteLength = BitsToBytes(representativeBitLength); T mgf; mgf.GenerateAndMask(hash, representative, representativeByteLength, digest, digest.size(), false); if (representativeBitLength % 8 != 0) representative[0] = (byte)Crop(representative[0], representativeBitLength % 8); } }; //! \class P1363_EMSA5 //! \brief EMSA5 padding method, for use with ESIGN //! \since Crypto++ 5.0 struct P1363_EMSA5 : public SignatureStandard { typedef EMSA5Pad SignatureMessageEncodingMethod; }; struct ESIGN_Keys { CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "ESIGN";} typedef ESIGNFunction PublicKey; typedef InvertibleESIGNFunction PrivateKey; }; //! \class ESIGN //! \brief ESIGN signature scheme, IEEE P1363a //! \tparam H HashTransformation derived class //! \tparam STANDARD Signature encoding method //! \since Crypto++ 5.0 template struct ESIGN : public TF_SS { }; NAMESPACE_END #endif