path: root/modes.h

#ifndef CRYPTOPP_MODES_H
#define CRYPTOPP_MODES_H

/*! \file
*/

#include "cryptlib.h"
#include "secblock.h"
#include "misc.h"
#include "strciphr.h"
#include "argnames.h"
#include "algparam.h"

NAMESPACE_BEGIN(CryptoPP)

//! Cipher mode documentation. See NIST SP 800-38A for definitions of these modes.

/*! Each class derived from this one defines two types, Encryption and Decryption, 
	both of which implement the SymmetricCipher interface.
	For each mode there are two classes, one of which is a template class,
	and the other one has a name that ends in "_ExternalCipher".
	The "external cipher" mode objects hold a reference to the underlying block cipher,
	instead of holding an instance of it. The reference must be passed in to the constructor.
	For the "cipher holder" classes, the CIPHER template parameter should be a class
	derived from BlockCipherDocumentation, for example DES or AES.
*/
struct CipherModeDocumentation : public SymmetricCipherDocumentation
{
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CipherModeBase : public SymmetricCipher
{
public:
	unsigned int MinKeyLength() const {return m_cipher->MinKeyLength();}
	unsigned int MaxKeyLength() const {return m_cipher->MaxKeyLength();}
	unsigned int DefaultKeyLength() const {return m_cipher->DefaultKeyLength();}
	unsigned int GetValidKeyLength(unsigned int n) const {return m_cipher->GetValidKeyLength(n);}
	bool IsValidKeyLength(unsigned int n) const {return m_cipher->IsValidKeyLength(n);}

	void SetKey(const byte *key, unsigned int length, const NameValuePairs &params = g_nullNameValuePairs);

	unsigned int OptimalDataAlignment() const {return BlockSize();}

	unsigned int IVSize() const {return BlockSize();}
	void GetNextIV(byte *IV);
	virtual IV_Requirement IVRequirement() const =0;

protected:
	inline unsigned int BlockSize() const {assert(m_register.size() > 0); return m_register.size();}
	virtual void SetFeedbackSize(unsigned int feedbackSize)
	{
		if (!(feedbackSize == 0 || feedbackSize == BlockSize()))
			throw InvalidArgument("CipherModeBase: feedback size cannot be specified for this cipher mode");
	}
	virtual void ResizeBuffers()
	{
		m_register.New(m_cipher->BlockSize());
	}
	virtual void UncheckedSetKey(const NameValuePairs &params, const byte *key, unsigned int length, const byte *iv) =0;

	BlockCipher *m_cipher;
	SecByteBlock m_register;
};

template <class POLICY_INTERFACE>
class CRYPTOPP_NO_VTABLE ModePolicyCommonTemplate : public CipherModeBase, public POLICY_INTERFACE
{
	unsigned int GetAlignment() const {return m_cipher->BlockAlignment();}
	void CipherSetKey(const NameValuePairs &params, const byte *key, unsigned int length);
};

template <class POLICY_INTERFACE>
void ModePolicyCommonTemplate<POLICY_INTERFACE>::CipherSetKey(const NameValuePairs &params, const byte *key, unsigned int length)
{
	m_cipher->SetKey(key, length, params);
	ResizeBuffers();
	int feedbackSize = params.GetIntValueWithDefault(Name::FeedbackSize(), 0);
	SetFeedbackSize(feedbackSize);
}

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CFB_ModePolicy : public ModePolicyCommonTemplate<CFB_CipherAbstractPolicy>
{
public:
	IV_Requirement IVRequirement() const {return RANDOM_IV;}
	static const char *StaticAlgorithmName() {return "CFB";}

protected:
	unsigned int GetBytesPerIteration() const {return m_feedbackSize;}
	byte * GetRegisterBegin() {return m_register + BlockSize() - m_feedbackSize;}
	void TransformRegister()
	{
		m_cipher->ProcessBlock(m_register, m_temp);
		memmove(m_register, m_register+m_feedbackSize, BlockSize()-m_feedbackSize);
		memcpy(m_register+BlockSize()-m_feedbackSize, m_temp, m_feedbackSize);
	}
	void CipherResynchronize(const byte *iv)
	{
		memcpy(m_register, iv, BlockSize());
		TransformRegister();
	}
	void SetFeedbackSize(unsigned int feedbackSize)
	{
		if (feedbackSize > BlockSize())
			throw InvalidArgument("CFB_Mode: invalid feedback size");
		m_feedbackSize = feedbackSize ? feedbackSize : BlockSize();
	}
	void ResizeBuffers()
	{
		CipherModeBase::ResizeBuffers();
		m_temp.New(BlockSize());
	}

	SecByteBlock m_temp;
	unsigned int m_feedbackSize;
};

inline void CopyOrZero(void *dest, const void *src, size_t s)
{
	if (src)
		memcpy(dest, src, s);
	else
		memset(dest, 0, s);
}

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE OFB_ModePolicy : public ModePolicyCommonTemplate<AdditiveCipherAbstractPolicy>
{
public:
	bool IsRandomAccess() const {return false;}
	IV_Requirement IVRequirement() const {return STRUCTURED_IV;}
	static const char *StaticAlgorithmName() {return "OFB";}

private:
	unsigned int GetBytesPerIteration() const {return BlockSize();}
	unsigned int GetIterationsToBuffer() const {return 1;}
	void WriteKeystream(byte *keystreamBuffer, unsigned int iterationCount)
	{
		assert(iterationCount == 1);
		m_cipher->ProcessBlock(keystreamBuffer);
		memcpy(m_register, keystreamBuffer, BlockSize());
	}
	void CipherResynchronize(byte *keystreamBuffer, const byte *iv)
	{
		CopyOrZero(keystreamBuffer, iv, BlockSize());
	}
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CTR_ModePolicy : public ModePolicyCommonTemplate<AdditiveCipherAbstractPolicy>
{
public:
	bool IsRandomAccess() const {return true;}
	IV_Requirement IVRequirement() const {return STRUCTURED_IV;}
	void GetNextIV(byte *IV);
	static const char *StaticAlgorithmName() {return "Counter-BE";}

private:
	unsigned int GetBytesPerIteration() const {return BlockSize();}
	unsigned int GetIterationsToBuffer() const {return m_cipher->OptimalNumberOfParallelBlocks();}
	void WriteKeystream(byte *buffer, unsigned int iterationCount)
		{OperateKeystream(WRITE_KEYSTREAM, buffer, NULL, iterationCount);}
	bool CanOperateKeystream() const {return true;}
	void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, unsigned int iterationCount);
	void CipherResynchronize(byte *keystreamBuffer, const byte *iv);
	void SeekToIteration(lword iterationCount);

	inline void ProcessMultipleBlocks(byte *output, const byte *input, unsigned int n);

	SecByteBlock m_counterArray;
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE BlockOrientedCipherModeBase : public CipherModeBase
{
public:
	void UncheckedSetKey(const NameValuePairs &params, const byte *key, unsigned int length, const byte *iv);
	unsigned int MandatoryBlockSize() const {return BlockSize();}
	bool IsRandomAccess() const {return false;}
	bool IsSelfInverting() const {return false;}
	bool IsForwardTransformation() const {return m_cipher->IsForwardTransformation();}
	void Resynchronize(const byte *iv) {memcpy(m_register, iv, BlockSize());}
	void ProcessData(byte *outString, const byte *inString, unsigned int length);

protected:
	bool RequireAlignedInput() const {return true;}
	virtual void ProcessBlocks(byte *outString, const byte *inString, unsigned int numberOfBlocks) =0;
	void ResizeBuffers()
	{
		CipherModeBase::ResizeBuffers();
		m_buffer.New(BlockSize());
	}

	SecByteBlock m_buffer;
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE ECB_OneWay : public BlockOrientedCipherModeBase
{
public:
	IV_Requirement IVRequirement() const {return NOT_RESYNCHRONIZABLE;}
	unsigned int OptimalBlockSize() const {return BlockSize() * m_cipher->OptimalNumberOfParallelBlocks();}
	void ProcessBlocks(byte *outString, const byte *inString, unsigned int numberOfBlocks)
		{m_cipher->ProcessAndXorMultipleBlocks(inString, NULL, outString, numberOfBlocks);}
	static const char *StaticAlgorithmName() {return "ECB";}
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_ModeBase : public BlockOrientedCipherModeBase
{
public:
	IV_Requirement IVRequirement() const {return UNPREDICTABLE_RANDOM_IV;}
	bool RequireAlignedInput() const {return false;}
	unsigned int MinLastBlockSize() const {return 0;}
	static const char *StaticAlgorithmName() {return "CBC";}
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_Encryption : public CBC_ModeBase
{
public:
	void ProcessBlocks(byte *outString, const byte *inString, unsigned int numberOfBlocks);
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_CTS_Encryption : public CBC_Encryption
{
public:
	void SetStolenIV(byte *iv) {m_stolenIV = iv;}
	unsigned int MinLastBlockSize() const {return BlockSize()+1;}
	void ProcessLastBlock(byte *outString, const byte *inString, unsigned int length);
	static const char *StaticAlgorithmName() {return "CBC/CTS";}

protected:
	void UncheckedSetKey(const NameValuePairs &params, const byte *key, unsigned int length, const byte *iv)
	{
		CBC_Encryption::UncheckedSetKey(params, key, length, iv);
		m_stolenIV = params.GetValueWithDefault(Name::StolenIV(), (byte *)NULL);
	}

	byte *m_stolenIV;
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_Decryption : public CBC_ModeBase
{
public:
	void ProcessBlocks(byte *outString, const byte *inString, unsigned int numberOfBlocks);
	
protected:
	void ResizeBuffers()
	{
		BlockOrientedCipherModeBase::ResizeBuffers();
		m_temp.New(BlockSize());
	}
	SecByteBlock m_temp;
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_CTS_Decryption : public CBC_Decryption
{
public:
	unsigned int MinLastBlockSize() const {return BlockSize()+1;}
	void ProcessLastBlock(byte *outString, const byte *inString, unsigned int length);
};

//! _
template <class CIPHER, class BASE>
class CipherModeFinalTemplate_CipherHolder : protected ObjectHolder<CIPHER>, public AlgorithmImpl<BASE, CipherModeFinalTemplate_CipherHolder<CIPHER, BASE> >
{
public:
	CipherModeFinalTemplate_CipherHolder()
	{
		this->m_cipher = &this->m_object;
		this->ResizeBuffers();
	}
	CipherModeFinalTemplate_CipherHolder(const byte *key, unsigned int length)
	{
		this->m_cipher = &this->m_object;
		this->SetKey(key, length);
	}
	CipherModeFinalTemplate_CipherHolder(const byte *key, unsigned int length, const byte *iv)
	{
		this->m_cipher = &this->m_object;
		this->SetKey(key, length, MakeParameters(Name::IV(), iv));
	}
	CipherModeFinalTemplate_CipherHolder(const byte *key, unsigned int length, const byte *iv, int feedbackSize)
	{
		this->m_cipher = &this->m_object;
		this->SetKey(key, length, MakeParameters(Name::IV(), iv)(Name::FeedbackSize(), feedbackSize));
	}

	static std::string StaticAlgorithmName()
		{return CIPHER::StaticAlgorithmName() + "/" + BASE::StaticAlgorithmName();}
};

//! _
template <class BASE>
class CipherModeFinalTemplate_ExternalCipher : public BASE
{
public:
	CipherModeFinalTemplate_ExternalCipher() {}
	CipherModeFinalTemplate_ExternalCipher(BlockCipher &cipher)
		{SetCipher(cipher);}
	CipherModeFinalTemplate_ExternalCipher(BlockCipher &cipher, const byte *iv, int feedbackSize = 0)
		{SetCipherWithIV(cipher, iv, feedbackSize);}

	void SetCipher(BlockCipher &cipher);
	void SetCipherWithIV(BlockCipher &cipher, const byte *iv, int feedbackSize = 0);
};

template <class BASE>
void CipherModeFinalTemplate_ExternalCipher<BASE>::SetCipher(BlockCipher &cipher)
{
	this->ThrowIfResynchronizable();
	this->m_cipher = &cipher;
	this->ResizeBuffers();
}

template <class BASE>
void CipherModeFinalTemplate_ExternalCipher<BASE>::SetCipherWithIV(BlockCipher &cipher, const byte *iv, int feedbackSize)
{
	this->ThrowIfInvalidIV(iv);
	this->m_cipher = &cipher;
	this->ResizeBuffers();
	this->SetFeedbackSize(feedbackSize);
	if (this->IsResynchronizable())
		this->Resynchronize(iv);
}

CRYPTOPP_DLL_TEMPLATE_CLASS CFB_CipherTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;
CRYPTOPP_DLL_TEMPLATE_CLASS CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;
CRYPTOPP_DLL_TEMPLATE_CLASS CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;

//! CFB mode
template <class CIPHER>
struct CFB_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Decryption;
};

//! CFB mode, external cipher
struct CFB_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Encryption;
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Decryption;
};

//! CFB mode FIPS variant, requiring full block plaintext according to FIPS 800-38A
template <class CIPHER>
struct CFB_FIPS_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Decryption;
};

//! CFB mode FIPS variant, requiring full block plaintext according to FIPS 800-38A, external cipher
struct CFB_FIPS_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Encryption;
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, OFB_ModePolicy> >;

//! OFB mode
template <class CIPHER>
struct OFB_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, OFB_ModePolicy> > > > Encryption;
	typedef Encryption Decryption;
};

//! OFB mode, external cipher
struct OFB_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, OFB_ModePolicy> > > > Encryption;
	typedef Encryption Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, CTR_ModePolicy> >;

//! CTR mode
template <class CIPHER>
struct CTR_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, CTR_ModePolicy> > > > Encryption;
	typedef Encryption Decryption;
};

//! CTR mode, external cipher
struct CTR_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, CTR_ModePolicy> > > > Encryption;
	typedef Encryption Decryption;
};

//! ECB mode
template <class CIPHER>
struct ECB_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ECB_OneWay> Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Decryption, ECB_OneWay> Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<ECB_OneWay>;

//! ECB mode, external cipher
struct ECB_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ECB_OneWay> Encryption;
	typedef Encryption Decryption;
};

//! CBC mode
template <class CIPHER>
struct CBC_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, CBC_Encryption> Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Decryption, CBC_Decryption> Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<CBC_Encryption>;
CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<CBC_Decryption>;

//! CBC mode, external cipher
struct CBC_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<CBC_Encryption> Encryption;
	typedef CipherModeFinalTemplate_ExternalCipher<CBC_Decryption> Decryption;
};

//! CBC mode with ciphertext stealing
template <class CIPHER>
struct CBC_CTS_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, CBC_CTS_Encryption> Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Decryption, CBC_CTS_Decryption> Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<CBC_CTS_Encryption>;
CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<CBC_CTS_Decryption>;

//! CBC mode with ciphertext stealing, external cipher
struct CBC_CTS_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<CBC_CTS_Encryption> Encryption;
	typedef CipherModeFinalTemplate_ExternalCipher<CBC_CTS_Decryption> Decryption;
};

#ifdef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY
typedef CFB_Mode_ExternalCipher::Encryption CFBEncryption;
typedef CFB_Mode_ExternalCipher::Decryption CFBDecryption;
typedef OFB_Mode_ExternalCipher::Encryption OFB;
typedef CTR_Mode_ExternalCipher::Encryption CounterMode;
#endif

NAMESPACE_END

#endif