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os/security/crypto/weakcrypto/source/symmetric/3des.cpp
author sl@SLION-WIN7.fritz.box
Fri, 15 Jun 2012 03:10:57 +0200
changeset 0 bde4ae8d615e
permissions -rw-r--r--
First public contribution. 
     1 /*

     2 * Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of the License "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description: 

    15 *

    16 */

    17 

    18 

    19 #include "3des.h"

    20 #include "../common/inlines.h"

    21 #include "des.inl"

    22 #include <cryptostrength.h>

    23 

    24 const TInt K3DESBlockBytes = 8;

    25 const TInt K3DESKeyBytes = 24;

    26 const TInt KDESKeyBytes = 8;

    27 

    28 void C3DES::Transform(TDes8& aBlock)

    29 	{

    30 	assert(aBlock.Size() == K3DESBlockBytes);

    31 		

    32 	TUint32 l, r;

    33 //	Split the block into 2 word-sized big endian portions

    34 	GetBlockBigEndian((TUint8*)&aBlock[0], l, r);

    35 

    36 	IPerm(l,r);

    37 

    38 	DoTransform(l, r, iK1);

    39 	DoTransform(r, l, iK2);

    40 	DoTransform(l, r, iK3);

    41 		

    42 	FPerm(l,r);

    43 

    44 //	Put the portions back into the block as little endian

    45 	PutBlockBigEndian((TUint8*)&aBlock[0], r, l);

    46 	}

    47 

    48 TInt C3DES::BlockSize() const

    49 	{

    50 	return K3DESBlockBytes;

    51 	}

    52 

    53 TInt C3DES::KeySize() const

    54 	{

    55 	return K3DESKeyBytes;

    56 	}

    57 

    58 C3DES::C3DES()

    59 	{

    60 	}

    61 

    62 void C3DES::ConstructL(const TDesC8& aKey)

    63 	{

    64 	assert(aKey.Size() == K3DESKeyBytes);

    65 

    66 	iKey = aKey.AllocL();

    67 	DoSetKey(*iKey);

    68 	}

    69 

    70 void C3DES::Reset()

    71 	{

    72 	DoSetKey(*iKey);

    73 	}

    74 

    75 /* C3DESEncryptor */

    76 

    77 EXPORT_C C3DESEncryptor* C3DESEncryptor::NewL(const TDesC8& aKey)

    78 	{

    79 	C3DESEncryptor* me = C3DESEncryptor::NewLC(aKey);

    80 	CleanupStack::Pop(me);

    81 	return (me);	

    82 	}

    83 

    84 EXPORT_C C3DESEncryptor* C3DESEncryptor::NewLC(const TDesC8& aKey)

    85 	{

    86 	C3DESEncryptor* me = new (ELeave) C3DESEncryptor();

    87 	CleanupStack::PushL(me);

    88 	me->ConstructL(aKey);

    89 	// DES only used 7 bits out of every key byte

    90 	TCrypto::IsSymmetricWeakEnoughL(BytesToBits(aKey.Size()) - aKey.Size());

    91 	return (me);	

    92 	}

    93 

    94 void C3DESEncryptor::DoSetKey(const TDesC8& aKey)

    95 	{

    96 	// Encryptor key	

    97 	SetKey(aKey.Mid(0, KDESKeyBytes), iK1);

    98 	// Decryptor key

    99 	SetKey(aKey.Mid(KDESKeyBytes, 2*KDESKeyBytes), iK2);

   100 	ReverseKeySchedule(iK2); // Reverse key schedule order

   101 	// Encryptor key

   102 	SetKey(aKey.Mid(2*KDESKeyBytes), iK3);

   103 	}

   104  

   105 /* C3DESDecryptor */

   106 

   107 EXPORT_C C3DESDecryptor* C3DESDecryptor::NewL(const TDesC8& aKey)

   108 	{

   109 	C3DESDecryptor* me = C3DESDecryptor::NewLC(aKey);

   110 	CleanupStack::Pop(me);

   111 	return (me);

   112 	}

   113 

   114 EXPORT_C C3DESDecryptor* C3DESDecryptor::NewLC(const TDesC8& aKey)

   115 	{

   116 	C3DESDecryptor* me = new (ELeave) C3DESDecryptor();

   117 	CleanupStack::PushL(me);

   118 	me->ConstructL(aKey);

   119 	// DES only used 7 bits out of every key byte

   120 	TCrypto::IsSymmetricWeakEnoughL(BytesToBits(aKey.Size()) - aKey.Size());

   121 	return (me);

   122 	}

   123 

   124 void C3DESDecryptor::DoSetKey(const TDesC8& aKey)

   125 	{

   126 	// 3DES decryption, reverse through key

   127 	// Decryptor key

   128 	CDES::SetKey(aKey.Mid(2*KDESKeyBytes), iK1);

   129 	ReverseKeySchedule(iK1);	//	Reverse key schedule order	

   130 

   131 	// Encryptor key

   132 	CDES::SetKey(aKey.Mid(KDESKeyBytes, 2*KDESKeyBytes), iK2);

   133 	

   134 	// Decryptor key

   135 	CDES::SetKey(aKey.Mid(0, KDESKeyBytes), iK3);

   136 	ReverseKeySchedule(iK3);	//	Reverse key schedule order

   137 	}

   138
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