147 lines
5.2 KiB
C++
147 lines
5.2 KiB
C++
// rw.h - originally written and placed in the public domain by Wei Dai
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/// \file rw.h
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/// \brief Classes for Rabin-Williams signature scheme
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/// \details The implementation provides Rabin-Williams signature schemes as defined in
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/// IEEE P1363. It uses Bernstein's tweaked square roots in place of square roots to
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/// speedup calculations.
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/// \sa <A HREF="http://cr.yp.to/sigs/rwsota-20080131.pdf">RSA signatures and Rabin–Williams
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/// signatures: the state of the art (20080131)</A>, Section 6, <em>The tweaks e and f</em>.
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/// \since Crypto++ 3.0
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#ifndef CRYPTOPP_RW_H
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#define CRYPTOPP_RW_H
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#include "cryptlib.h"
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#include "pubkey.h"
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#include "integer.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief Rabin-Williams trapdoor function using the public key
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/// \since Crypto++ 3.0, Tweaked roots using <em>e</em> and <em>f</em> since Crypto++ 5.6.4
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class CRYPTOPP_DLL RWFunction : public TrapdoorFunction, public PublicKey
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{
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typedef RWFunction ThisClass;
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public:
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/// \brief Initialize a Rabin-Williams public key
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/// \param n the modulus
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void Initialize(const Integer &n)
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{m_n = n;}
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void BERDecode(BufferedTransformation &bt);
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void DEREncode(BufferedTransformation &bt) const;
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void Save(BufferedTransformation &bt) const
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{DEREncode(bt);}
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void Load(BufferedTransformation &bt)
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{BERDecode(bt);}
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Integer ApplyFunction(const Integer &x) const;
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Integer PreimageBound() const {return ++(m_n>>1);}
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Integer ImageBound() const {return m_n;}
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bool Validate(RandomNumberGenerator &rng, unsigned int level) const;
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bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
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void AssignFrom(const NameValuePairs &source);
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const Integer& GetModulus() const {return m_n;}
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void SetModulus(const Integer &n) {m_n = n;}
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protected:
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Integer m_n;
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};
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/// \brief Rabin-Williams trapdoor function using the private key
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/// \since Crypto++ 3.0, Tweaked roots using <em>e</em> and <em>f</em> since Crypto++ 5.6.4
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class CRYPTOPP_DLL InvertibleRWFunction : public RWFunction, public TrapdoorFunctionInverse, public PrivateKey
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{
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typedef InvertibleRWFunction ThisClass;
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public:
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/// \brief Construct an InvertibleRWFunction
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InvertibleRWFunction() : m_precompute(false) {}
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/// \brief Initialize a Rabin-Williams private key
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/// \param n modulus
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/// \param p first prime factor
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/// \param q second prime factor
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/// \param u q<sup>-1</sup> mod p
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/// \details This Initialize() function overload initializes a private key from existing parameters.
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void Initialize(const Integer &n, const Integer &p, const Integer &q, const Integer &u);
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/// \brief Create a Rabin-Williams private key
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/// \param rng a RandomNumberGenerator derived class
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/// \param modulusBits the size of the modulus, in bits
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/// \details This function overload of Initialize() creates a new private key because it
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/// takes a RandomNumberGenerator() as a parameter. If you have an existing keypair,
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/// then use one of the other Initialize() overloads.
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void Initialize(RandomNumberGenerator &rng, unsigned int modulusBits)
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{GenerateRandomWithKeySize(rng, modulusBits);}
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void BERDecode(BufferedTransformation &bt);
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void DEREncode(BufferedTransformation &bt) const;
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void Save(BufferedTransformation &bt) const
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{DEREncode(bt);}
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void Load(BufferedTransformation &bt)
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{BERDecode(bt);}
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Integer CalculateInverse(RandomNumberGenerator &rng, const Integer &x) const;
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// GeneratibleCryptoMaterial
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bool Validate(RandomNumberGenerator &rng, unsigned int level) const;
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bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
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void AssignFrom(const NameValuePairs &source);
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/*! parameters: (ModulusSize) */
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void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg);
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const Integer& GetPrime1() const {return m_p;}
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const Integer& GetPrime2() const {return m_q;}
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const Integer& GetMultiplicativeInverseOfPrime2ModPrime1() const {return m_u;}
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void SetPrime1(const Integer &p) {m_p = p;}
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void SetPrime2(const Integer &q) {m_q = q;}
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void SetMultiplicativeInverseOfPrime2ModPrime1(const Integer &u) {m_u = u;}
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virtual bool SupportsPrecomputation() const {return true;}
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virtual void Precompute(unsigned int unused = 0) {CRYPTOPP_UNUSED(unused); PrecomputeTweakedRoots();}
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virtual void Precompute(unsigned int unused = 0) const {CRYPTOPP_UNUSED(unused); PrecomputeTweakedRoots();}
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virtual void LoadPrecomputation(BufferedTransformation &storedPrecomputation);
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virtual void SavePrecomputation(BufferedTransformation &storedPrecomputation) const;
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protected:
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void PrecomputeTweakedRoots() const;
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protected:
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Integer m_p, m_q, m_u;
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mutable Integer m_pre_2_9p, m_pre_2_3q, m_pre_q_p;
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mutable bool m_precompute;
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};
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/// \brief Rabin-Williams keys
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/// \since Crypto++ 3.0
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struct RW
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{
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CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "RW";}
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typedef RWFunction PublicKey;
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typedef InvertibleRWFunction PrivateKey;
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};
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/// \brief Rabin-Williams signature scheme
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/// \tparam STANDARD signature standard
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/// \tparam H hash transformation
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/// \since Crypto++ 3.0
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template <class STANDARD, class H>
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struct RWSS : public TF_SS<RW, STANDARD, H>
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{
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};
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NAMESPACE_END
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#endif
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