VeraCrypt/src/Volume/Cipher.cpp

/*
 Copyright (c) 2008-2010 TrueCrypt Developers Association. All rights reserved.

 Governed by the TrueCrypt License 3.0 the full text of which is contained in
 the file License.txt included in TrueCrypt binary and source code distribution
 packages.
*/

#include "Platform/Platform.h"
#include "Cipher.h"
#include "Crypto/Aes.h"
#include "Crypto/Serpent.h"
#include "Crypto/Twofish.h"

#ifdef TC_AES_HW_CPU
#	include "Crypto/Aes_hw_cpu.h"
#endif

namespace VeraCrypt
{
	Cipher::Cipher () : Initialized (false)
	{
	}

	Cipher::~Cipher ()
	{
	}

	void Cipher::DecryptBlock (byte *data) const
	{
		if (!Initialized)
			throw NotInitialized (SRC_POS);

		Decrypt (data);
	}

	void Cipher::DecryptBlocks (byte *data, size_t blockCount) const
	{
		if (!Initialized)
			throw NotInitialized (SRC_POS);

		while (blockCount-- > 0)
		{
			Decrypt (data);
			data += GetBlockSize();
		}
	}

	void Cipher::EncryptBlock (byte *data) const
	{
		if (!Initialized)
			throw NotInitialized (SRC_POS);

		Encrypt (data);
	}

	void Cipher::EncryptBlocks (byte *data, size_t blockCount) const
	{
		if (!Initialized)
			throw NotInitialized (SRC_POS);

		while (blockCount-- > 0)
		{
			Encrypt (data);
			data += GetBlockSize();
		}
	}

	CipherList Cipher::GetAvailableCiphers ()
	{
		CipherList l;

		l.push_back (shared_ptr <Cipher> (new CipherAES ()));
		l.push_back (shared_ptr <Cipher> (new CipherSerpent ()));
		l.push_back (shared_ptr <Cipher> (new CipherTwofish ()));

		return l;
	}

	void Cipher::SetKey (const ConstBufferPtr &key)
	{
		if (key.Size() != GetKeySize ())
			throw ParameterIncorrect (SRC_POS);

		if (!Initialized)
			ScheduledKey.Allocate (GetScheduledKeySize ());

		SetCipherKey (key);
		Key.CopyFrom (key);
		Initialized = true;
	}

#define TC_EXCEPTION(TYPE) TC_SERIALIZER_FACTORY_ADD(TYPE)
#undef TC_EXCEPTION_NODECL
#define TC_EXCEPTION_NODECL(TYPE) TC_SERIALIZER_FACTORY_ADD(TYPE)

	TC_SERIALIZER_FACTORY_ADD_EXCEPTION_SET (CipherException);


	// AES
	void CipherAES::Decrypt (byte *data) const
	{
#ifdef TC_AES_HW_CPU
		if (IsHwSupportAvailable())
			aes_hw_cpu_decrypt (ScheduledKey.Ptr() + sizeof (aes_encrypt_ctx), data);
		else
#endif
			aes_decrypt (data, data, (aes_decrypt_ctx *) (ScheduledKey.Ptr() + sizeof (aes_encrypt_ctx)));
	}

	void CipherAES::DecryptBlocks (byte *data, size_t blockCount) const
	{
		if (!Initialized)
			throw NotInitialized (SRC_POS);

#ifdef TC_AES_HW_CPU
		if ((blockCount & (32 - 1)) == 0
			&& IsHwSupportAvailable())
		{
			while (blockCount > 0)
			{
				aes_hw_cpu_decrypt_32_blocks (ScheduledKey.Ptr() + sizeof (aes_encrypt_ctx), data);

				data += 32 * GetBlockSize();
				blockCount -= 32;
			}
		}
		else
#endif
			Cipher::DecryptBlocks (data, blockCount);
	}

	void CipherAES::Encrypt (byte *data) const
	{
#ifdef TC_AES_HW_CPU
		if (IsHwSupportAvailable())
			aes_hw_cpu_encrypt (ScheduledKey.Ptr(), data);
		else
#endif
			aes_encrypt (data, data, (aes_encrypt_ctx *) ScheduledKey.Ptr());
	}

	void CipherAES::EncryptBlocks (byte *data, size_t blockCount) const
	{
		if (!Initialized)
			throw NotInitialized (SRC_POS);

#ifdef TC_AES_HW_CPU
		if ((blockCount & (32 - 1)) == 0
			&& IsHwSupportAvailable())
		{
			while (blockCount > 0)
			{
				aes_hw_cpu_encrypt_32_blocks (ScheduledKey.Ptr(), data);

				data += 32 * GetBlockSize();
				blockCount -= 32;
			}
		}
		else
#endif
			Cipher::EncryptBlocks (data, blockCount);
	}

	size_t CipherAES::GetScheduledKeySize () const
	{
		return sizeof(aes_encrypt_ctx) + sizeof(aes_decrypt_ctx);
	}

	bool CipherAES::IsHwSupportAvailable () const
	{
#ifdef TC_AES_HW_CPU
		static bool state = false;
		static bool stateValid = false;

		if (!stateValid)
		{
			state = is_aes_hw_cpu_supported() ? true : false;
			stateValid = true;
		}
		return state && HwSupportEnabled;
#else
		return false;
#endif
	}

	void CipherAES::SetCipherKey (const byte *key)
	{
		if (aes_encrypt_key256 (key, (aes_encrypt_ctx *) ScheduledKey.Ptr()) != EXIT_SUCCESS)
			throw CipherInitError (SRC_POS);

		if (aes_decrypt_key256 (key, (aes_decrypt_ctx *) (ScheduledKey.Ptr() + sizeof (aes_encrypt_ctx))) != EXIT_SUCCESS)
			throw CipherInitError (SRC_POS);
	}

	// Serpent
	void CipherSerpent::Decrypt (byte *data) const
	{
		serpent_decrypt (data, data, ScheduledKey);
	}

	void CipherSerpent::Encrypt (byte *data) const
	{
		serpent_encrypt (data, data, ScheduledKey);
	}
	
	size_t CipherSerpent::GetScheduledKeySize () const
	{
		return 140*4;
	}

	void CipherSerpent::SetCipherKey (const byte *key)
	{
		serpent_set_key (key, ScheduledKey);
	}


	// Twofish
	void CipherTwofish::Decrypt (byte *data) const
	{
		twofish_decrypt ((TwofishInstance *) ScheduledKey.Ptr(), (unsigned int *)data, (unsigned int *)data);
	}

	void CipherTwofish::Encrypt (byte *data) const
	{
		twofish_encrypt ((TwofishInstance *) ScheduledKey.Ptr(), (unsigned int *)data, (unsigned int *)data);
	}

	size_t CipherTwofish::GetScheduledKeySize () const
	{
		return TWOFISH_KS;
	}

	void CipherTwofish::SetCipherKey (const byte *key)
	{
		twofish_set_key ((TwofishInstance *) ScheduledKey.Ptr(), (unsigned int *) key);
	}


	bool Cipher::HwSupportEnabled = true;
}