rw.h
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// rw.h - originally written and placed in the public domain by Wei Dai
/// \file rw.h
/// \brief Classes for Rabin-Williams signature scheme
/// \details The implementation provides Rabin-Williams signature schemes as defined in
/// IEEE P1363. It uses Bernstein's tweaked square roots in place of square roots to
/// speedup calculations.
/// \sa <A HREF="http://cr.yp.to/sigs/rwsota-20080131.pdf">RSA signatures and Rabin–Williams
/// signatures: the state of the art (20080131)</A>, Section 6, <em>The tweaks e and f</em>.
/// \since Crypto++ 3.0
#ifndef CRYPTOPP_RW_H
#define CRYPTOPP_RW_H
#include "cryptlib.h"
#include "pubkey.h"
#include "integer.h"
NAMESPACE_BEGIN(CryptoPP)
/// \brief Rabin-Williams trapdoor function using the public key
/// \since Crypto++ 3.0, Tweaked roots using <em>e</em> and <em>f</em> since Crypto++ 5.6.4
class CRYPTOPP_DLL RWFunction : public TrapdoorFunction, public PublicKey
{
typedef RWFunction ThisClass;
public:
/// \brief Initialize a Rabin-Williams public key
/// \param n the modulus
void Initialize(const Integer &n)
{m_n = n;}
void BERDecode(BufferedTransformation &bt);
void DEREncode(BufferedTransformation &bt) const;
void Save(BufferedTransformation &bt) const
{DEREncode(bt);}
void Load(BufferedTransformation &bt)
{BERDecode(bt);}
Integer ApplyFunction(const Integer &x) const;
Integer PreimageBound() const {return ++(m_n>>1);}
Integer ImageBound() const {return m_n;}
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);
const Integer& GetModulus() const {return m_n;}
void SetModulus(const Integer &n) {m_n = n;}
protected:
Integer m_n;
};
/// \brief Rabin-Williams trapdoor function using the private key
/// \since Crypto++ 3.0, Tweaked roots using <em>e</em> and <em>f</em> since Crypto++ 5.6.4
class CRYPTOPP_DLL InvertibleRWFunction : public RWFunction, public TrapdoorFunctionInverse, public PrivateKey
{
typedef InvertibleRWFunction ThisClass;
public:
/// \brief Construct an InvertibleRWFunction
InvertibleRWFunction() : m_precompute(false) {}
/// \brief Initialize a Rabin-Williams private key
/// \param n modulus
/// \param p first prime factor
/// \param q second prime factor
/// \param u q<sup>-1</sup> mod p
/// \details This Initialize() function overload initializes a private key from existing parameters.
void Initialize(const Integer &n, const Integer &p, const Integer &q, const Integer &u);
/// \brief Create a Rabin-Williams private key
/// \param rng a RandomNumberGenerator derived class
/// \param modulusBits the size of the modulus, 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);}
void BERDecode(BufferedTransformation &bt);
void DEREncode(BufferedTransformation &bt) const;
void Save(BufferedTransformation &bt) const
{DEREncode(bt);}
void Load(BufferedTransformation &bt)
{BERDecode(bt);}
Integer CalculateInverse(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;}
const Integer& GetMultiplicativeInverseOfPrime2ModPrime1() const {return m_u;}
void SetPrime1(const Integer &p) {m_p = p;}
void SetPrime2(const Integer &q) {m_q = q;}
void SetMultiplicativeInverseOfPrime2ModPrime1(const Integer &u) {m_u = u;}
virtual bool SupportsPrecomputation() const {return true;}
virtual void Precompute(unsigned int unused = 0) {CRYPTOPP_UNUSED(unused); PrecomputeTweakedRoots();}
virtual void Precompute(unsigned int unused = 0) const {CRYPTOPP_UNUSED(unused); PrecomputeTweakedRoots();}
virtual void LoadPrecomputation(BufferedTransformation &storedPrecomputation);
virtual void SavePrecomputation(BufferedTransformation &storedPrecomputation) const;
protected:
void PrecomputeTweakedRoots() const;
protected:
Integer m_p, m_q, m_u;
mutable Integer m_pre_2_9p, m_pre_2_3q, m_pre_q_p;
mutable bool m_precompute;
};
/// \brief Rabin-Williams keys
/// \since Crypto++ 3.0
struct RW
{
CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "RW";}
typedef RWFunction PublicKey;
typedef InvertibleRWFunction PrivateKey;
};
/// \brief Rabin-Williams signature scheme
/// \tparam STANDARD signature standard
/// \tparam H hash transformation
/// \since Crypto++ 3.0
template <class STANDARD, class H>
struct RWSS : public TF_SS<RW, STANDARD, H>
{
};
NAMESPACE_END
#endif
BufferedTransformation
Interface for buffered transformations.
Definition: cryptlib.h:1652
CryptoMaterial::Precompute
virtual void Precompute(unsigned int precomputationStorage)
Perform precomputation.
Definition: cryptlib.h:2472
GeneratableCryptoMaterial::GenerateRandomWithKeySize
void GenerateRandomWithKeySize(RandomNumberGenerator &rng, unsigned int keySize)
Generate a random key or crypto parameters.
Integer
Multiple precision integer with arithmetic operations.
Definition: integer.h:50
InvertibleRWFunction
Rabin-Williams trapdoor function using the private key.
Definition: rw.h:60
InvertibleRWFunction::LoadPrecomputation
virtual void LoadPrecomputation(BufferedTransformation &storedPrecomputation)
Retrieve previously saved precomputation.
InvertibleRWFunction::Validate
bool Validate(RandomNumberGenerator &rng, unsigned int level) const
Check this object for errors.
InvertibleRWFunction::Save
void Save(BufferedTransformation &bt) const
Saves a key to a BufferedTransformation.
Definition: rw.h:87
InvertibleRWFunction::AssignFrom
void AssignFrom(const NameValuePairs &source)
Assign values to this object.
InvertibleRWFunction::Load
void Load(BufferedTransformation &bt)
Loads a key from a BufferedTransformation.
Definition: rw.h:89
InvertibleRWFunction::Initialize
void Initialize(const Integer &n, const Integer &p, const Integer &q, const Integer &u)
Initialize a Rabin-Williams private key.
InvertibleRWFunction::Initialize
void Initialize(RandomNumberGenerator &rng, unsigned int modulusBits)
Create a Rabin-Williams private key.
Definition: rw.h:81
InvertibleRWFunction::SupportsPrecomputation
virtual bool SupportsPrecomputation() const
Determines whether the object supports precomputation.
Definition: rw.h:109
InvertibleRWFunction::SavePrecomputation
virtual void SavePrecomputation(BufferedTransformation &storedPrecomputation) const
Save precomputation for later use.
InvertibleRWFunction::GetVoidValue
bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
Get a named value.
InvertibleRWFunction::GenerateRandom
void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg)
InvertibleRWFunction::InvertibleRWFunction
InvertibleRWFunction()
Construct an InvertibleRWFunction.
Definition: rw.h:65
InvertibleRWFunction::Precompute
virtual void Precompute(unsigned int unused=0)
Perform precomputation.
Definition: rw.h:110
InvertibleRWFunction::CalculateInverse
Integer CalculateInverse(RandomNumberGenerator &rng, const Integer &x) const
Calculates the inverse of an element.
NameValuePairs
Interface for retrieving values given their names.
Definition: cryptlib.h:322
PrivateKey
Interface for private keys.
Definition: cryptlib.h:2541
PublicKey
Interface for public keys.
Definition: cryptlib.h:2536
RWFunction
Rabin-Williams trapdoor function using the public key.
Definition: rw.h:24
RWFunction::PreimageBound
Integer PreimageBound() const
Returns the maximum size of a message before the trapdoor function is applied.
Definition: rw.h:43
RWFunction::ApplyFunction
Integer ApplyFunction(const Integer &x) const
Applies the trapdoor.
RWFunction::ImageBound
Integer ImageBound() const
Returns the maximum size of a message after the trapdoor function is applied.
Definition: rw.h:44
RWFunction::Save
void Save(BufferedTransformation &bt) const
Saves a key to a BufferedTransformation.
Definition: rw.h:37
RWFunction::Initialize
void Initialize(const Integer &n)
Initialize a Rabin-Williams public key.
Definition: rw.h:31
RWFunction::AssignFrom
void AssignFrom(const NameValuePairs &source)
Assign values to this object.
RWFunction::GetVoidValue
bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
Get a named value.
RWFunction::Load
void Load(BufferedTransformation &bt)
Loads a key from a BufferedTransformation.
Definition: rw.h:39
RWFunction::Validate
bool Validate(RandomNumberGenerator &rng, unsigned int level) const
Check this object for errors.
RandomNumberGenerator
Interface for random number generators.
Definition: cryptlib.h:1435
TF_SS
Trapdoor Function (TF) Signature Scheme.
Definition: pubkey.h:2316
TrapdoorFunction
Applies the trapdoor function.
Definition: pubkey.h:126
TrapdoorFunctionInverse
Applies the inverse of the trapdoor function.
Definition: pubkey.h:179
cryptlib.h
Abstract base classes that provide a uniform interface to this library.
integer.h
Multiple precision integer with arithmetic operations.
CryptoPP
Crypto++ library namespace.
pubkey.h
This file contains helper classes/functions for implementing public key algorithms.
RW
Rabin-Williams keys.
Definition: rw.h:129
RWSS
Rabin-Williams signature scheme.
Definition: rw.h:141