sl@0: /*
sl@0: * Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of the License "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description: 
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: #include "des.h"
sl@0: #include "destables.h"
sl@0: #include "../common/inlines.h"
sl@0: #include "des.inl"
sl@0: #include <cryptostrength.h>
sl@0: 
sl@0: const TInt KDESBlockBytes = 8;
sl@0: const TInt KDESKeyBytes = 8;
sl@0: 
sl@0: //	bit 0 is left-most in byte
sl@0: static const TInt bytebit[] = {0200,0100,040,020,010,04,02,01};
sl@0: 
sl@0: void CDES::Transform(TDes8& aBlock)
sl@0: 	{
sl@0: 	assert(aBlock.Size() == KDESBlockBytes);
sl@0: 
sl@0: 	TUint32 l, r;
sl@0: 	// Split the block into 2 word-sized big endian portions
sl@0: 	GetBlockBigEndian((TUint8*)&aBlock[0], l, r);
sl@0: 
sl@0: 	IPerm(l,r);
sl@0: 
sl@0: 	CDES::DoTransform(l, r, iK1);
sl@0: 		
sl@0: 	FPerm(l,r);
sl@0: 
sl@0: 	// Put the portions back into the block as little endian
sl@0: 	PutBlockBigEndian((TUint8*)&aBlock[0], r, l);
sl@0: 	}
sl@0: 
sl@0: void CDES::DoTransform(TUint32& l, TUint32& r, const TUint32* aKey)
sl@0: 	{
sl@0: 	TInt i = 0;
sl@0: 	for (; i<8; i++)
sl@0: 		{
sl@0: 		TUint32 work = rotrFixed(r, 4U) ^ aKey[4*i+0];
sl@0: 		l ^= DES_TABLE::sbox[6][(work) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[4][(work >> 8) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[2][(work >> 16) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[0][(work >> 24) & 0x3f];
sl@0: 		work = r ^ aKey[4*i+1];
sl@0: 		l ^= DES_TABLE::sbox[7][(work) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[5][(work >> 8) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[3][(work >> 16) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[1][(work >> 24) & 0x3f];
sl@0: 
sl@0: 		work = rotrFixed(l, 4U) ^ aKey[4*i+2];
sl@0: 		r ^= DES_TABLE::sbox[6][(work) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[4][(work >> 8) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[2][(work >> 16) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[0][(work >> 24) & 0x3f];
sl@0: 		work = l ^ aKey[4*i+3];
sl@0: 		r ^= DES_TABLE::sbox[7][(work) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[5][(work >> 8) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[3][(work >> 16) & 0x3f]
sl@0: 		  ^  DES_TABLE::sbox[1][(work >> 24) & 0x3f];
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: 
sl@0: TInt CDES::BlockSize() const
sl@0: 	{
sl@0: 	return KDESBlockBytes;
sl@0: 	}
sl@0: 
sl@0: TInt CDES::KeySize() const
sl@0: 	{
sl@0: 	return KDESKeyBytes;
sl@0: 	}
sl@0: 
sl@0: CDES::~CDES()
sl@0: 	{
sl@0: 	delete iKey;
sl@0: 	}
sl@0: 
sl@0: void CDES::ConstructL(const TDesC8& aKey, TBool /*aCheckWeakKey*/)
sl@0: 	{
sl@0: 	assert(aKey.Size() == KDESKeyBytes);
sl@0: 
sl@0: 	iKey = aKey.AllocL();
sl@0: 	SetKey(aKey, iK1);
sl@0: 	}
sl@0: 
sl@0: CDES::CDES()
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: typedef TUint8 TKeyDES[KDESKeyBytes];
sl@0: const TInt KKnownWeakKeysCount = 16;
sl@0: const TKeyDES weak_keys[KKnownWeakKeysCount] =
sl@0: 	{
sl@0: 	/* weak keys */
sl@0: 	{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
sl@0: 	{0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE},
sl@0: 	{0x1E,0x1E,0x1E,0x1E,0x0E,0x0E,0x0E,0x0E},
sl@0: 	{0xE0,0xE0,0xE0,0xE0,0xF0,0xF0,0xF0,0xF0},
sl@0: 	{0x00,0xFE,0x00,0xFE,0x00,0xFE,0x00,0xFE},
sl@0: 	{0xFE,0x00,0xFE,0x00,0xFE,0x00,0xFE,0x00},
sl@0: 	{0x1E,0xE0,0x1E,0xE0,0x0E,0xF0,0x0E,0xF0},
sl@0: 	{0xE0,0x1E,0xE0,0x1E,0xF0,0x0E,0xF0,0x0E},
sl@0: 	{0x00,0xE0,0x00,0xE0,0x00,0xF0,0x00,0xF0},
sl@0: 	{0xE0,0x00,0xE0,0x00,0xF0,0x00,0xF0,0x00},
sl@0: 	{0x1E,0xFE,0x1E,0xFE,0x0E,0xFE,0x0E,0xFE},
sl@0: 	{0xFE,0x1E,0xFE,0x1E,0xFE,0x0E,0xFE,0x0E},
sl@0: 	{0x00,0x1E,0x00,0x1E,0x00,0x0E,0x00,0x0E},
sl@0: 	{0x1E,0x00,0x1E,0x00,0x0E,0x00,0x0E,0x00},
sl@0: 	{0xE0,0xFE,0xE0,0xFE,0xF0,0xFE,0xF0,0xFE},
sl@0: 	{0xFE,0xE0,0xFE,0xE0,0xFE,0xF0,0xFE,0xF0}
sl@0: 	};
sl@0: 
sl@0: void CDES::SetKey(const TDesC8& aKey, TUint32* aKeyBuffer)
sl@0: 	{
sl@0: 	TInt i=0, j=0, l=0, m=0;
sl@0: 
sl@0: //	Form a byte array from aKey, taking endianess into account (little->big)	
sl@0: 	TUint8 key[8];								//	For big endian byte array	
sl@0: 	Mem::Copy(&key, &aKey[0], 8);
sl@0: 
sl@0: 	TUint8 buffer[56+56+8];
sl@0: 	TUint8* const pc1m = &buffer[0];			/* place to modify pc1 into */
sl@0: 	TUint8* const pcr = pc1m + 56;				/* place to rotate pc1 into */
sl@0: 	TUint8* const ks = pcr + 56;
sl@0: 
sl@0: 	for (j=0; j<56; j++) 
sl@0: 		{/* convert pc1 to bits of key */
sl@0: 		l = DES_TABLE::pc1[j]-1;				/* integer bit location  */
sl@0: 		m = l & 07;								/* find bit              */
sl@0: 		pc1m[j]=(key[l>>3] &					/* find which key byte l is in */
sl@0: 			bytebit[m])							/* and which bit of that byte */
sl@0: 			? (TUint8)1 : (TUint8)0;			/* and store 1-bit result */
sl@0: 		}
sl@0: 
sl@0: 	for (i=0; i<16; i++) 
sl@0: 		{/* key chunk for each iteration */
sl@0: 		Mem::FillZ(ks,8);							/* Clear key schedule */
sl@0: 		for (j=0; j<56; j++)
sl@0: 		/*	rotate pc1 the right amount */
sl@0: 			pcr[j] = pc1m[(l=j+DES_TABLE::totrot[i])<(j<28? 28 : 56) ? l: l-28];
sl@0: 		
sl@0: 		/* rotate left and right halves independently */
sl@0: 		
sl@0: 		for (j=0; j<48; j++)
sl@0: 			{/* select bits individually */
sl@0: 			/* check bit that goes to ks[j] */
sl@0: 			if (pcr[DES_TABLE::pc2[j]-1])
sl@0: 				{/* mask it in if it's there */
sl@0: 				l= j % 6;
sl@0: 				ks[j/6] |= bytebit[l] >> 2;
sl@0: 				}
sl@0: 			}
sl@0: 
sl@0: 		/* Now convert to odd/even interleaved form for use in F */
sl@0: 		(*(aKeyBuffer+(2*i))) = ((TUint32)ks[0] << 24)
sl@0: 			| ((TUint32)ks[2] << 16)
sl@0: 			| ((TUint32)ks[4] << 8)
sl@0: 			| ((TUint32)ks[6]);
sl@0: 		
sl@0: 		(*(aKeyBuffer+(2*i+1))) = ((TUint32)ks[1] << 24)
sl@0: 			| ((TUint32)ks[3] << 16)
sl@0: 			| ((TUint32)ks[5] << 8)
sl@0: 			| ((TUint32)ks[7]);
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: void CDES::Reset()
sl@0: 	{
sl@0: 	SetKey(*iKey, iK1);
sl@0: 	}
sl@0: 
sl@0: 
sl@0: /* CDESEncryptor */
sl@0: 
sl@0: EXPORT_C CDESEncryptor* CDESEncryptor::NewL(const TDesC8& aKey, 
sl@0: 	TBool aCheckWeakKey)
sl@0: 	{
sl@0: 	CDESEncryptor* me = CDESEncryptor::NewLC(aKey, aCheckWeakKey);
sl@0: 	CleanupStack::Pop(me);
sl@0: 	return (me);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CDESEncryptor* CDESEncryptor::NewLC(const TDesC8& aKey, 
sl@0: 	TBool aCheckWeakKey)
sl@0: 	{
sl@0: 	CDESEncryptor* me = new (ELeave) CDESEncryptor();
sl@0: 	CleanupStack::PushL(me);
sl@0: 	me->ConstructL(aKey, aCheckWeakKey);
sl@0: 	// DES only used 7 bits out of every key byte
sl@0: 	TCrypto::IsSymmetricWeakEnoughL(BytesToBits(aKey.Size()) - aKey.Size());
sl@0: 	return (me);
sl@0: 	}
sl@0: 
sl@0: CDESEncryptor::CDESEncryptor()
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: /* CDESDecryptor */
sl@0: 
sl@0: EXPORT_C CDESDecryptor* CDESDecryptor::NewL(const TDesC8& aKey, 
sl@0: 	TBool aCheckWeakKey)
sl@0: 	{
sl@0: 	CDESDecryptor* me = CDESDecryptor::NewLC(aKey, aCheckWeakKey);
sl@0: 	CleanupStack::Pop(me);
sl@0: 	return (me);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C CDESDecryptor* CDESDecryptor::NewLC(const TDesC8& aKey, 
sl@0: 	TBool aCheckWeakKey)
sl@0: 	{
sl@0: 	CDESDecryptor* me = new (ELeave) CDESDecryptor();
sl@0: 	CleanupStack::PushL(me);
sl@0: 	me->ConstructL(aKey, aCheckWeakKey);
sl@0: 	// DES only used 7 bits out of every key byte
sl@0: 	TCrypto::IsSymmetricWeakEnoughL(BytesToBits(aKey.Size()) - aKey.Size());
sl@0: 	return (me);
sl@0: 	}
sl@0: 
sl@0: 
sl@0: CDESDecryptor::CDESDecryptor()
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: void CDESDecryptor::SetKey(const TDesC8& aKey, TUint32* aKeyBuffer)
sl@0: 	{
sl@0: 	CDES::SetKey(aKey, aKeyBuffer);
sl@0: 
sl@0: 	ReverseKeySchedule(iK1);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C TBool CDES::IsWeakKey(const TDesC8& aKey)
sl@0: 	{
sl@0: 	TKeyDES key;
sl@0: 	TInt index = 0;
sl@0: 	//Reset parity bits
sl@0: 	for(; index < KDESKeyBytes; index++)
sl@0: 		{
sl@0: 		key[index] = aKey[index] & 0xFE;
sl@0: 		}
sl@0: 		
sl@0: 	TBool weak = EFalse;	
sl@0: 	//Compare key with potential weak keys without parity	
sl@0: 	for (index=0; index < KKnownWeakKeysCount; index++)
sl@0: 		{
sl@0: 		if (Mem::Compare(weak_keys[index], KDESKeyBytes, &key[0], KDESKeyBytes)==0)
sl@0: 			{
sl@0: 			weak = ETrue;
sl@0: 			break;
sl@0: 			}
sl@0: 		}
sl@0: 	return weak;
sl@0: 	}
sl@0: