source: trunk/src-cryptopp/seckey.h

// seckey.h - written and placed in the public domain by Wei Dai

//! \file
//! \brief Classes and functions for implementing secret key algorithms.

#ifndef CRYPTOPP_SECKEY_H
#define CRYPTOPP_SECKEY_H

#include "config.h"

#if CRYPTOPP_MSC_VERSION
# pragma warning(push)
# pragma warning(disable: 4189)
#endif

#include "cryptlib.h"
#include "misc.h"
#include "simple.h"

NAMESPACE_BEGIN(CryptoPP)

//! \brief Inverts the cipher's direction
//! \param dir the cipher's direction
//! \returns DECRYPTION if \ref CipherDir "dir" is ENCRYPTION, DECRYPTION otherwise
inline CipherDir ReverseCipherDir(CipherDir dir)
{
        return (dir == ENCRYPTION) ? DECRYPTION : ENCRYPTION;
}

//! \class FixedBlockSize
//! \brief Inherited by algorithms with fixed block size
//! \tparam N the blocksize of the algorithm
template <unsigned int N>
class FixedBlockSize
{
public:
        //! \brief The block size of the algorithm provided as a constant.
        CRYPTOPP_CONSTANT(BLOCKSIZE = N)
};

// ************** rounds ***************

//! \class FixedRounds
//! \brief Inherited by algorithms with fixed number of rounds
//! \tparam R the number of rounds used by the algorithm
template <unsigned int R>
class FixedRounds
{
public:
        //! \brief The number of rounds for the algorithm provided as a constant.
        CRYPTOPP_CONSTANT(ROUNDS = R)
};

//! \class VariableRounds
//! \brief Inherited by algorithms with variable number of rounds
//! \tparam D Default number of rounds
//! \tparam N Minimum number of rounds
//! \tparam D Maximum number of rounds
template <unsigned int D, unsigned int N=1, unsigned int M=INT_MAX>             // use INT_MAX here because enums are treated as signed ints
class VariableRounds
{
public:
        //! \brief The default number of rounds for the algorithm provided as a constant.
        CRYPTOPP_CONSTANT(DEFAULT_ROUNDS = D)
        //! \brief The minimum number of rounds for the algorithm provided as a constant.
        CRYPTOPP_CONSTANT(MIN_ROUNDS = N)
        //! \brief The maximum number of rounds for the algorithm provided as a constant.
        CRYPTOPP_CONSTANT(MAX_ROUNDS = M)
        //! \brief The default number of rounds for the algorithm based on key length
        //!   provided by a static function.
        //! \param keylength the size of the key, in bytes
        //! \details keylength is unused in the default implementation.
        CRYPTOPP_CONSTEXPR static unsigned int StaticGetDefaultRounds(size_t keylength)
        {
                // Comma operator breaks Debug builds with GCC 4.0 - 4.6.
                // Also see http://github.com/weidai11/cryptopp/issues/255
#if defined(CRYPTOPP_CXX11_CONSTEXPR)
                return CRYPTOPP_UNUSED(keylength), static_cast<unsigned int>(DEFAULT_ROUNDS);
#else
                CRYPTOPP_UNUSED(keylength);
                return static_cast<unsigned int>(DEFAULT_ROUNDS);
#endif
        }

protected:
        //! \brief Validates the number of rounds for an algorithm.
        //! \param rounds the candidate number of rounds
        //! \param alg an Algorithm object used if the number of rounds are invalid
        //! \throws InvalidRounds if the number of rounds are invalid
        //! \details ThrowIfInvalidRounds() validates the number of rounds and throws if invalid.
        inline void ThrowIfInvalidRounds(int rounds, const Algorithm *alg)
        {
                if (M == INT_MAX) // Coverity and result_independent_of_operands
                {
                        if (rounds < MIN_ROUNDS)
                                throw InvalidRounds(alg ? alg->AlgorithmName() : std::string("VariableRounds"), rounds);
                }
                else
                {
                        if (rounds < MIN_ROUNDS || rounds > MAX_ROUNDS)
                                throw InvalidRounds(alg ? alg->AlgorithmName() : std::string("VariableRounds"), rounds);
                }
        }

        //! \brief Validates the number of rounds for an algorithm
        //! \param param the candidate number of rounds
        //! \param alg an Algorithm object used if the number of rounds are invalid
        //! \returns the number of rounds for the algorithm
        //! \throws InvalidRounds if the number of rounds are invalid
        //! \details GetRoundsAndThrowIfInvalid() validates the number of rounds and throws if invalid.
        inline unsigned int GetRoundsAndThrowIfInvalid(const NameValuePairs &param, const Algorithm *alg)
        {
                int rounds = param.GetIntValueWithDefault("Rounds", DEFAULT_ROUNDS);
                ThrowIfInvalidRounds(rounds, alg);
                return (unsigned int)rounds;
        }
};

// ************** key length ***************

//! \class FixedKeyLength
//! \brief Inherited by keyed algorithms with fixed key length
//! \tparam N Default key length, in bytes
//! \tparam IV_REQ the \ref SimpleKeyingInterface::IV_Requirement "IV requirements"
//! \tparam IV_L default IV length, in bytes
//! \sa SimpleKeyingInterface
template <unsigned int N, unsigned int IV_REQ = SimpleKeyingInterface::NOT_RESYNCHRONIZABLE, unsigned int IV_L = 0>
class FixedKeyLength
{
public:
        //! \brief The default key length used by the algorithm provided as a constant
        //! \details KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(KEYLENGTH=N)
        //! \brief The minimum key length used by the algorithm provided as a constant
        //! \details MIN_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(MIN_KEYLENGTH=N)
        //! \brief The maximum key length used by the algorithm provided as a constant
        //! \details MAX_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(MAX_KEYLENGTH=N)
        //! \brief The default key length used by the algorithm provided as a constant
        //! \details DEFAULT_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(DEFAULT_KEYLENGTH=N)
        //! \brief The default IV requirements for the algorithm provided as a constant
        //! \details The default value is NOT_RESYNCHRONIZABLE. See IV_Requirement
        //!  in cryptlib.h for allowed values.
        CRYPTOPP_CONSTANT(IV_REQUIREMENT = IV_REQ)
        //! \brief The default IV length used by the algorithm provided as a constant
        //! \details IV_LENGTH is provided in bytes, not bits. The default implementation uses 0.
        CRYPTOPP_CONSTANT(IV_LENGTH = IV_L)
        //! \brief The default key length for the algorithm provided by a static function.
        //! \param keylength the size of the key, in bytes
        //! \details The default implementation returns KEYLENGTH. keylength is unused
        //!   in the default implementation.
        CRYPTOPP_CONSTEXPR static size_t CRYPTOPP_API StaticGetValidKeyLength(size_t keylength)
        {
                // Comma operator breaks Debug builds with GCC 4.0 - 4.6.
                // Also see http://github.com/weidai11/cryptopp/issues/255
#if defined(CRYPTOPP_CXX11_CONSTEXPR)
                return CRYPTOPP_UNUSED(keylength), static_cast<size_t>(KEYLENGTH);
#else
                CRYPTOPP_UNUSED(keylength);
                return static_cast<size_t>(KEYLENGTH);
#endif
        }
};

//! \class VariableKeyLength
//! \brief Inherited by keyed algorithms with variable key length
//! \tparam D Default key length, in bytes
//! \tparam N Minimum key length, in bytes
//! \tparam M Maximum key length, in bytes
//! \tparam M Default key length multiple, in bytes. The default multiple is 1.
//! \tparam IV_REQ the \ref SimpleKeyingInterface::IV_Requirement "IV requirements"
//! \tparam IV_L default IV length, in bytes. The default length is 0.
//! \sa SimpleKeyingInterface
template <unsigned int D, unsigned int N, unsigned int M, unsigned int Q = 1, unsigned int IV_REQ = SimpleKeyingInterface::NOT_RESYNCHRONIZABLE, unsigned int IV_L = 0>
class VariableKeyLength
{
        // Make these private to avoid Doxygen documenting them in all derived classes
        CRYPTOPP_COMPILE_ASSERT(Q > 0);
        CRYPTOPP_COMPILE_ASSERT(N % Q == 0);
        CRYPTOPP_COMPILE_ASSERT(M % Q == 0);
        CRYPTOPP_COMPILE_ASSERT(N < M);
        CRYPTOPP_COMPILE_ASSERT(D >= N);
        CRYPTOPP_COMPILE_ASSERT(M >= D);

public:
        //! \brief The minimum key length used by the algorithm provided as a constant
        //! \details MIN_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(MIN_KEYLENGTH=N)
        //! \brief The maximum key length used by the algorithm provided as a constant
        //! \details MAX_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(MAX_KEYLENGTH=M)
        //! \brief The default key length used by the algorithm provided as a constant
        //! \details DEFAULT_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(DEFAULT_KEYLENGTH=D)
        //! \brief The key length multiple used by the algorithm provided as a constant
        //! \details MAX_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(KEYLENGTH_MULTIPLE=Q)
        //! \brief The default IV requirements for the algorithm provided as a constant
        //! \details The default value is NOT_RESYNCHRONIZABLE. See IV_Requirement
        //!  in cryptlib.h for allowed values.
        CRYPTOPP_CONSTANT(IV_REQUIREMENT=IV_REQ)
        //! \brief The default initialization vector length for the algorithm provided as a constant
        //! \details IV_LENGTH is provided in bytes, not bits. The default implementation uses 0.
        CRYPTOPP_CONSTANT(IV_LENGTH=IV_L)
        //! \brief Provides a valid key length for the algorithm provided by a static function.
        //! \param keylength the size of the key, in bytes
        //! \details If keylength is less than MIN_KEYLENGTH, then the function returns
        //!   MIN_KEYLENGTH. If keylength is greater than MAX_KEYLENGTH, then the function
        //!   returns MAX_KEYLENGTH. If keylength is a multiple of KEYLENGTH_MULTIPLE,
        //!   then keylength is returned. Otherwise, the function returns keylength rounded
        //!   \a down to the next smaller multiple of KEYLENGTH_MULTIPLE.
        //! \details keylength is provided in bytes, not bits.
        // TODO: Figure out how to make this CRYPTOPP_CONSTEXPR
        static size_t CRYPTOPP_API StaticGetValidKeyLength(size_t keylength)
        {
                if (keylength < (size_t)MIN_KEYLENGTH)
                        return MIN_KEYLENGTH;
                else if (keylength > (size_t)MAX_KEYLENGTH)
                        return (size_t)MAX_KEYLENGTH;
                else
                {
                        keylength += KEYLENGTH_MULTIPLE-1;
                        return keylength - keylength%KEYLENGTH_MULTIPLE;
                }
        }
};

//! \class SameKeyLengthAs
//! \brief Provides key lengths based on another class's key length
//! \tparam T another FixedKeyLength or VariableKeyLength class
//! \tparam IV_REQ the \ref SimpleKeyingInterface::IV_Requirement "IV requirements"
//! \tparam IV_L default IV length, in bytes
//! \sa SimpleKeyingInterface
template <class T, unsigned int IV_REQ = SimpleKeyingInterface::NOT_RESYNCHRONIZABLE, unsigned int IV_L = 0>
class SameKeyLengthAs
{
public:
        //! \brief The minimum key length used by the algorithm provided as a constant
        //! \details MIN_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(MIN_KEYLENGTH=T::MIN_KEYLENGTH)
        //! \brief The maximum key length used by the algorithm provided as a constant
        //! \details MIN_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(MAX_KEYLENGTH=T::MAX_KEYLENGTH)
        //! \brief The default key length used by the algorithm provided as a constant
        //! \details MIN_KEYLENGTH is provided in bytes, not bits
        CRYPTOPP_CONSTANT(DEFAULT_KEYLENGTH=T::DEFAULT_KEYLENGTH)
        //! \brief The default IV requirements for the algorithm provided as a constant
        //! \details The default value is NOT_RESYNCHRONIZABLE. See IV_Requirement
        //!  in cryptlib.h for allowed values.
        CRYPTOPP_CONSTANT(IV_REQUIREMENT=IV_REQ)
        //! \brief The default initialization vector length for the algorithm provided as a constant
        //! \details IV_LENGTH is provided in bytes, not bits. The default implementation uses 0.
        CRYPTOPP_CONSTANT(IV_LENGTH=IV_L)
        //! \brief Provides a valid key length for the algorithm provided by a static function.
        //! \param keylength the size of the key, in bytes
        //! \details If keylength is less than MIN_KEYLENGTH, then the function returns
        //!   MIN_KEYLENGTH. If keylength is greater than MAX_KEYLENGTH, then the function
        //!   returns MAX_KEYLENGTH. If keylength is a multiple of KEYLENGTH_MULTIPLE,
        //!   then keylength is returned. Otherwise, the function returns keylength rounded
        //!   \a down to the next smaller multiple of KEYLENGTH_MULTIPLE.
        //! \details keylength is provided in bytes, not bits.
        CRYPTOPP_CONSTEXPR static size_t CRYPTOPP_API StaticGetValidKeyLength(size_t keylength)
                {return T::StaticGetValidKeyLength(keylength);}
};

// ************** implementation helper for SimpleKeyingInterface ***************

//! \class SimpleKeyingInterfaceImpl
//! \brief Provides a base implementation of SimpleKeyingInterface
//! \tparam BASE a SimpleKeyingInterface derived class
//! \tparam INFO a SimpleKeyingInterface derived class
//! \details SimpleKeyingInterfaceImpl() provides a default implementation for ciphers providing a keying interface.
//!   Functions are virtual and not eligible for C++11 <tt>constexpr</tt>-ness.
//! \sa Algorithm(), SimpleKeyingInterface()
template <class BASE, class INFO = BASE>
class CRYPTOPP_NO_VTABLE SimpleKeyingInterfaceImpl : public BASE
{
public:
        //! \brief The minimum key length used by the algorithm
        //! \returns minimum key length used by the algorithm, in bytes
        size_t MinKeyLength() const
                {return INFO::MIN_KEYLENGTH;}

        //! \brief The maximum key length used by the algorithm
        //! \returns maximum key length used by the algorithm, in bytes
        size_t MaxKeyLength() const
                {return (size_t)INFO::MAX_KEYLENGTH;}

        //! \brief The default key length used by the algorithm
        //! \returns default key length used by the algorithm, in bytes
        size_t DefaultKeyLength() const
                {return INFO::DEFAULT_KEYLENGTH;}

        //! \brief Provides a valid key length for the algorithm
        //! \param keylength the size of the key, in bytes
        //! \returns the valid key lenght, in bytes
        //! \details keylength is provided in bytes, not bits. If keylength is less than MIN_KEYLENGTH,
        //!   then the function returns MIN_KEYLENGTH. If keylength is greater than MAX_KEYLENGTH,
        //!   then the function returns MAX_KEYLENGTH. if If keylength is a multiple of KEYLENGTH_MULTIPLE,
        //!   then keylength is returned. Otherwise, the function returns a \a lower multiple of
        //!   KEYLENGTH_MULTIPLE.
        size_t GetValidKeyLength(size_t keylength) const {return INFO::StaticGetValidKeyLength(keylength);}

        //! \brief The default IV requirements for the algorithm
        //! \details The default value is NOT_RESYNCHRONIZABLE. See IV_Requirement
        //!  in cryptlib.h for allowed values.
        SimpleKeyingInterface::IV_Requirement IVRequirement() const
                {return (SimpleKeyingInterface::IV_Requirement)INFO::IV_REQUIREMENT;}

        //! \brief The default initialization vector length for the algorithm
        //! \details IVSize is provided in bytes, not bits. The default implementation uses IV_LENGTH, which is 0.
        unsigned int IVSize() const
                {return INFO::IV_LENGTH;}
};

//! \class BlockCipherImpl
//! \brief Provides a base implementation of Algorithm and SimpleKeyingInterface for block ciphers
//! \tparam INFO a SimpleKeyingInterface derived class
//! \tparam BASE a SimpleKeyingInterface derived class
//! \details BlockCipherImpl() provides a default implementation for block ciphers using AlgorithmImpl()
//!   and SimpleKeyingInterfaceImpl(). Functions are virtual and not eligible for C++11 <tt>constexpr</tt>-ness.
//! \sa Algorithm(), SimpleKeyingInterface(), AlgorithmImpl(), SimpleKeyingInterfaceImpl()
template <class INFO, class BASE = BlockCipher>
class CRYPTOPP_NO_VTABLE BlockCipherImpl : public AlgorithmImpl<SimpleKeyingInterfaceImpl<TwoBases<BASE, INFO> > >
{
public:
        //! Provides the block size of the algorithm
        //! \returns the block size of the algorithm, in bytes
        unsigned int BlockSize() const {return this->BLOCKSIZE;}
};

//! \class BlockCipherFinal
//! \brief Provides class member functions to key a block cipher
//! \tparam DIR a CipherDir
//! \tparam BASE a BlockCipherImpl derived class
template <CipherDir DIR, class BASE>
class BlockCipherFinal : public ClonableImpl<BlockCipherFinal<DIR, BASE>, BASE>
{
public:
        //! \brief Construct a default BlockCipherFinal
        //! \details The cipher is not keyed.
        BlockCipherFinal() {}

        //! \brief Construct a BlockCipherFinal
        //! \param key a byte array used to key the cipher
        //! \details key must be at least DEFAULT_KEYLENGTH in length. Internally, the function calls
        //!    SimpleKeyingInterface::SetKey.
        BlockCipherFinal(const byte *key)
                {this->SetKey(key, this->DEFAULT_KEYLENGTH);}

        //! \brief Construct a BlockCipherFinal
        //! \param key a byte array used to key the cipher
        //! \param length the length of the byte array
        //! \details key must be at least DEFAULT_KEYLENGTH in length. Internally, the function calls
        //!    SimpleKeyingInterface::SetKey.
        BlockCipherFinal(const byte *key, size_t length)
                {this->SetKey(key, length);}

        //! \brief Construct a BlockCipherFinal
        //! \param key a byte array used to key the cipher
        //! \param length the length of the byte array
        //! \param rounds the number of rounds
        //! \details key must be at least DEFAULT_KEYLENGTH in length. Internally, the function calls
        //!    SimpleKeyingInterface::SetKeyWithRounds.
        BlockCipherFinal(const byte *key, size_t length, unsigned int rounds)
                {this->SetKeyWithRounds(key, length, rounds);}

        //! \brief Provides the direction of the cipher
        //! \returns true if DIR is ENCRYPTION, false otherwise
        //! \sa GetCipherDirection(), IsPermutation()
        bool IsForwardTransformation() const {return DIR == ENCRYPTION;}
};

//! \class MessageAuthenticationCodeImpl
//! \brief Provides a base implementation of Algorithm and SimpleKeyingInterface for message authentication codes
//! \tparam INFO a SimpleKeyingInterface derived class
//! \tparam BASE a SimpleKeyingInterface derived class
//! \details MessageAuthenticationCodeImpl() provides a default implementation for message authentication codes
//!   using AlgorithmImpl() and SimpleKeyingInterfaceImpl(). Functions are virtual and not subject to C++11
//!   <tt>constexpr</tt>.
//! \sa Algorithm(), SimpleKeyingInterface(), AlgorithmImpl(), SimpleKeyingInterfaceImpl()
template <class BASE, class INFO = BASE>
class MessageAuthenticationCodeImpl : public AlgorithmImpl<SimpleKeyingInterfaceImpl<BASE, INFO>, INFO>
{
};

//! \class MessageAuthenticationCodeFinal
//! \brief Provides class member functions to key a message authentication code
//! \tparam DIR a CipherDir
//! \tparam BASE a BlockCipherImpl derived class
template <class BASE>
class MessageAuthenticationCodeFinal : public ClonableImpl<MessageAuthenticationCodeFinal<BASE>, MessageAuthenticationCodeImpl<BASE> >
{
public:
        //! \brief Construct a default MessageAuthenticationCodeFinal
        //! \details The message authentication code is not keyed.
        MessageAuthenticationCodeFinal() {}
        //! \brief Construct a BlockCipherFinal
        //! \param key a byte array used to key the algorithm
        //! \details key must be at least DEFAULT_KEYLENGTH in length. Internally, the function calls
        //!    SimpleKeyingInterface::SetKey.
        MessageAuthenticationCodeFinal(const byte *key)
                {this->SetKey(key, this->DEFAULT_KEYLENGTH);}
        //! \brief Construct a BlockCipherFinal
        //! \param key a byte array used to key the algorithm
        //! \param length the length of the byte array
        //! \details key must be at least DEFAULT_KEYLENGTH in length. Internally, the function calls
        //!    SimpleKeyingInterface::SetKey.
        MessageAuthenticationCodeFinal(const byte *key, size_t length)
                {this->SetKey(key, length);}
};

// ************** documentation ***************

//! \class BlockCipherDocumentation
//! \brief Provides Encryption and Decryption typedefs used by derived classes to
//!    implement a block cipher
//! \details These objects usually should not be used directly. See CipherModeDocumentation
//!    instead. Each class derived from this one defines two types, Encryption and Decryption,
//!    both of which implement the BlockCipher interface.
struct BlockCipherDocumentation
{
        //! implements the BlockCipher interface
        typedef BlockCipher Encryption;
        //! implements the BlockCipher interface
        typedef BlockCipher Decryption;
};

//! \class SymmetricCipherDocumentation
//! \brief Provides Encryption and Decryption typedefs used by derived classes to
//!    implement a symmetric cipher
//! \details Each class derived from this one defines two types, Encryption and Decryption,
//!    both of which implement the SymmetricCipher interface. Two types of classes derive
//!    from this class: stream ciphers and block cipher modes. Stream ciphers can be used
//!    alone, cipher mode classes need to be used with a block cipher. See CipherModeDocumentation
//!    for more for information about using cipher modes and block ciphers.
struct SymmetricCipherDocumentation
{
        //! implements the SymmetricCipher interface
        typedef SymmetricCipher Encryption;
        //! implements the SymmetricCipher interface
        typedef SymmetricCipher Decryption;
};

//! \class AuthenticatedSymmetricCipherDocumentation
//! \brief Provides Encryption and Decryption typedefs used by derived classes to
//!    implement an authenticated encryption cipher
//! \details Each class derived from this one defines two types, Encryption and Decryption,
//!    both of which implement the AuthenticatedSymmetricCipher interface.
struct AuthenticatedSymmetricCipherDocumentation
{
        //! implements the AuthenticatedSymmetricCipher interface
        typedef AuthenticatedSymmetricCipher Encryption;
        //! implements the AuthenticatedSymmetricCipher interface
        typedef AuthenticatedSymmetricCipher Decryption;
};

NAMESPACE_END

#if CRYPTOPP_MSC_VERSION
# pragma warning(pop)
#endif

#endif