Crypto++ 7.0 Free C++ class library of cryptographic schemes

rw.h
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1 // rw.h - originally written and placed in the public domain by Wei Dai
2
3 /// \file rw.h
4 /// \brief Classes for Rabin-Williams signature scheme
5 /// \details The implementation provides Rabin-Williams signature schemes as defined in
6 /// IEEE P1363. It uses Bernstein's tweaked square roots in place of square roots to
7 /// speedup calculations.
8 /// \sa <A HREF="http://cr.yp.to/sigs/rwsota-20080131.pdf">RSA signatures and Rabin–Williams
9 /// signatures: the state of the art (20080131)</A>, Section 6, <em>The tweaks e and f</em>.
10 /// \since Crypto++ 3.0
11
12 #ifndef CRYPTOPP_RW_H
13 #define CRYPTOPP_RW_H
14
15 #include "cryptlib.h"
16 #include "pubkey.h"
17 #include "integer.h"
18
19 NAMESPACE_BEGIN(CryptoPP)
20
21 /// \brief Rabin-Williams trapdoor function using the public key
22 /// \since Crypto++ 3.0, Tweaked roots using <em>e</em> and <em>f</em> since Crypto++ 5.6.4
23 class CRYPTOPP_DLL RWFunction : public TrapdoorFunction, public PublicKey
24 {
25 typedef RWFunction ThisClass;
26
27 public:
28
29 /// \brief Initialize a Rabin-Williams public key
30 /// \param n the modulus
31 void Initialize(const Integer &n)
32 {m_n = n;}
33
34 void BERDecode(BufferedTransformation &bt);
35 void DEREncode(BufferedTransformation &bt) const;
36
37 void Save(BufferedTransformation &bt) const
38 {DEREncode(bt);}
39 void Load(BufferedTransformation &bt)
40 {BERDecode(bt);}
41
42 Integer ApplyFunction(const Integer &x) const;
43 Integer PreimageBound() const {return ++(m_n>>1);}
44 Integer ImageBound() const {return m_n;}
45
46 bool Validate(RandomNumberGenerator &rng, unsigned int level) const;
47 bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
48 void AssignFrom(const NameValuePairs &source);
49
50 const Integer& GetModulus() const {return m_n;}
51 void SetModulus(const Integer &n) {m_n = n;}
52
53 protected:
54 Integer m_n;
55 };
56
57 /// \brief Rabin-Williams trapdoor function using the private key
58 /// \since Crypto++ 3.0, Tweaked roots using <em>e</em> and <em>f</em> since Crypto++ 5.6.4
59 class CRYPTOPP_DLL InvertibleRWFunction : public RWFunction, public TrapdoorFunctionInverse, public PrivateKey
60 {
61 typedef InvertibleRWFunction ThisClass;
62
63 public:
64 /// \brief Construct an InvertibleRWFunction
65 InvertibleRWFunction() : m_precompute(false) {}
66
67 /// \brief Initialize a Rabin-Williams private key
68 /// \param n modulus
69 /// \param p first prime factor
70 /// \param q second prime factor
71 /// \param u q<sup>-1</sup> mod p
72 /// \details This Initialize() function overload initializes a private key from existing parameters.
73 void Initialize(const Integer &n, const Integer &p, const Integer &q, const Integer &u);
74
75 /// \brief Create a Rabin-Williams private key
76 /// \param rng a RandomNumberGenerator derived class
77 /// \param modulusBits the size of the modulus, in bits
78 /// \details This function overload of Initialize() creates a new private key because it
79 /// takes a RandomNumberGenerator() as a parameter. If you have an existing keypair,
80 /// then use one of the other Initialize() overloads.
81 void Initialize(RandomNumberGenerator &rng, unsigned int modulusBits)
82 {GenerateRandomWithKeySize(rng, modulusBits);}
83
84 void BERDecode(BufferedTransformation &bt);
85 void DEREncode(BufferedTransformation &bt) const;
86
87 void Save(BufferedTransformation &bt) const
88 {DEREncode(bt);}
89 void Load(BufferedTransformation &bt)
90 {BERDecode(bt);}
91
92 Integer CalculateInverse(RandomNumberGenerator &rng, const Integer &x) const;
93
94 // GeneratibleCryptoMaterial
95 bool Validate(RandomNumberGenerator &rng, unsigned int level) const;
96 bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const;
97 void AssignFrom(const NameValuePairs &source);
98 /*! parameters: (ModulusSize) */
99 void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg);
100
101 const Integer& GetPrime1() const {return m_p;}
102 const Integer& GetPrime2() const {return m_q;}
103 const Integer& GetMultiplicativeInverseOfPrime2ModPrime1() const {return m_u;}
104
105 void SetPrime1(const Integer &p) {m_p = p;}
106 void SetPrime2(const Integer &q) {m_q = q;}
107 void SetMultiplicativeInverseOfPrime2ModPrime1(const Integer &u) {m_u = u;}
108
109 virtual bool SupportsPrecomputation() const {return true;}
110 virtual void Precompute(unsigned int unused = 0) {CRYPTOPP_UNUSED(unused); PrecomputeTweakedRoots();}
111 virtual void Precompute(unsigned int unused = 0) const {CRYPTOPP_UNUSED(unused); PrecomputeTweakedRoots();}
112
113 virtual void LoadPrecomputation(BufferedTransformation &storedPrecomputation);
114 virtual void SavePrecomputation(BufferedTransformation &storedPrecomputation) const;
115
116 protected:
117 void PrecomputeTweakedRoots() const;
118
119 protected:
120 Integer m_p, m_q, m_u;
121
122 mutable Integer m_pre_2_9p, m_pre_2_3q, m_pre_q_p;
123 mutable bool m_precompute;
124 };
125
126 /// \brief Rabin-Williams keys
127 /// \since Crypto++ 3.0
128 struct RW
129 {
130 CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "RW";}
131 typedef RWFunction PublicKey;
132 typedef InvertibleRWFunction PrivateKey;
133 };
134
135 /// \brief Rabin-Williams signature scheme
136 /// \tparam STANDARD signature standard
137 /// \tparam H hash transformation
138 /// \since Crypto++ 3.0
139 template <class STANDARD, class H>
140 struct RWSS : public TF_SS<RW, STANDARD, H>
141 {
142 };
143
144 NAMESPACE_END
145
146 #endif
CryptoMaterial::AssignFrom
virtual void AssignFrom(const NameValuePairs &source)=0
Assign values to this object.
CryptoMaterial::Precompute
virtual void Precompute(unsigned int precomputationStorage)
Perform precomputation.
Definition: cryptlib.h:2332
InvertibleRWFunction
Rabin-Williams trapdoor function using the private key.
Definition: rw.h:59
InvertibleRWFunction::Save
void Save(BufferedTransformation &bt) const
Saves a key to a BufferedTransformation.
Definition: rw.h:87
pubkey.h
This file contains helper classes/functions for implementing public key algorithms.
RWFunction::Load
void Load(BufferedTransformation &bt)
Loads a key from a BufferedTransformation.
Definition: rw.h:39
InvertibleRWFunction::SupportsPrecomputation
virtual bool SupportsPrecomputation() const
Determines whether the object supports precomputation.
Definition: rw.h:109
cryptlib.h
Abstract base classes that provide a uniform interface to this library.
RandomNumberGenerator
Interface for random number generators.
Definition: cryptlib.h:1349
RWFunction::PreimageBound
Integer PreimageBound() const
Returns the maximum size of a message before the trapdoor function is applied.
Definition: rw.h:43
BufferedTransformation
Interface for buffered transformations.
Definition: cryptlib.h:1564
RWFunction::ImageBound
Integer ImageBound() const
Returns the maximum size of a message after the trapdoor function is applied.
Definition: rw.h:44
PrivateKey
Interface for private keys.
Definition: cryptlib.h:2396
CryptoMaterial::SavePrecomputation
virtual void SavePrecomputation(BufferedTransformation &storedPrecomputation) const
Save precomputation for later use.
Definition: cryptlib.h:2348
TrapdoorFunctionInverse
Applies the inverse of the trapdoor function.
Definition: pubkey.h:178
CryptoMaterial::LoadPrecomputation
virtual void LoadPrecomputation(BufferedTransformation &storedPrecomputation)
Retrieve previously saved precomputation.
Definition: cryptlib.h:2341
RWFunction
Rabin-Williams trapdoor function using the public key.
Definition: rw.h:23
CryptoMaterial::Validate
virtual bool Validate(RandomNumberGenerator &rng, unsigned int level) const =0
Check this object for errors.
InvertibleRWFunction::Initialize
void Initialize(RandomNumberGenerator &rng, unsigned int modulusBits)
Create a Rabin-Williams private key.
Definition: rw.h:81
Integer
Multiple precision integer with arithmetic operations.
Definition: integer.h:49
NameValuePairs::GetVoidValue
virtual bool GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const =0
Get a named value.
TrapdoorFunction
Applies the trapdoor function.
Definition: pubkey.h:125
InvertibleRWFunction::Load
void Load(BufferedTransformation &bt)
Loads a key from a BufferedTransformation.
Definition: rw.h:89
TrapdoorFunctionInverse::CalculateInverse
virtual Integer CalculateInverse(RandomNumberGenerator &rng, const Integer &x) const =0
Calculates the inverse of an element.
RWFunction::Initialize
void Initialize(const Integer &n)
Initialize a Rabin-Williams public key.
Definition: rw.h:31
RWSS
Rabin-Williams signature scheme.
Definition: rw.h:140
GeneratableCryptoMaterial::GenerateRandom
virtual void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &params=g_nullNameValuePairs)
Generate a random key or crypto parameters.
Definition: cryptlib.h:2376
GeneratableCryptoMaterial::GenerateRandomWithKeySize
void GenerateRandomWithKeySize(RandomNumberGenerator &rng, unsigned int keySize)
Generate a random key or crypto parameters.
Definition: cryptlib.cpp:811
integer.h
Multiple precision integer with arithmetic operations.
PublicKey
Interface for public keys.
Definition: cryptlib.h:2391
CryptoPP
Crypto++ library namespace.
InvertibleRWFunction::Precompute
virtual void Precompute(unsigned int unused=0)
Perform precomputation.
Definition: rw.h:110
RW
Rabin-Williams keys.
Definition: rw.h:128
RWFunction::Save
void Save(BufferedTransformation &bt) const
Saves a key to a BufferedTransformation.
Definition: rw.h:37
InvertibleRWFunction::InvertibleRWFunction
InvertibleRWFunction()
Construct an InvertibleRWFunction.
Definition: rw.h:65
NameValuePairs
Interface for retrieving values given their names.
Definition: cryptlib.h:293
TF_SS
Trapdoor Function (TF) Signature Scheme.
Definition: pubkey.h:2249