1 /*

     2 * Copyright (c) 2006-2009 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 "rsaimpl.h"

    20 #include "rsafunction.h"

    21 #include "pluginconfig.h"

    22 #include <cryptopanic.h>

    23 #include <cryptostrength.h>

    24 #include <securityerr.h>

    25 

    26 using namespace SoftwareCrypto;

    27 

    28 /* CRSAImpl */

    29 CRSAImpl::CRSAImpl(

    30 	TUid aCryptoMode,

    31 	TUid aPadding) :

    32 	CAsymmetricCipherImpl(aCryptoMode, aPadding)

    33 	{

    34 	}

    35 

    36 CRSAImpl* CRSAImpl::NewL(const CKey& aKey, TUid aCryptoMode, TUid aPadding)

    37 	{

    38 	CRSAImpl* self = CRSAImpl::NewLC(aKey, aCryptoMode, aPadding);

    39 	CleanupStack::Pop(self);

    40 	return self;

    41 	}

    42 	

    43 CRSAImpl* CRSAImpl::NewLC(const CKey& aKey, TUid aCryptoMode, TUid aPadding)

    44 	{

    45 	CRSAImpl* self = new(ELeave) CRSAImpl(aCryptoMode, aPadding);

    46 	CleanupStack::PushL(self);

    47 	self->ConstructL(aKey);

    48 	return self;

    49 	}

    50 	

    51 CRSAImpl::~CRSAImpl()

    52 	{

    53 	}

    54 	

    55 TInt CRSAImpl::GetMaximumOutputLengthL() const

    56 	{

    57 	const TInteger& N = iKey->GetBigIntL(KRsaKeyParameterNUid);

    58 	

    59 	if (iCryptoMode.iUid == KCryptoModeDecrypt)

    60 		return N.ByteCount() - iPadding->MinPaddingLength();

    61 	else

    62 		return N.ByteCount();

    63 	}

    64 	

    65 TInt CRSAImpl::GetMaximumInputLengthL() const

    66 	{

    67 	const TInteger& N = iKey->GetBigIntL(KRsaKeyParameterNUid);

    68 	

    69 	if (iCryptoMode.iUid == KCryptoModeEncrypt)

    70 		return N.ByteCount() - iPadding->MinPaddingLength();

    71 	else

    72 		return N.ByteCount();

    73 	}

    74 	

    75 void CRSAImpl::ConstructL(const CKey& aKey)

    76 	{

    77 	const TInteger& N = aKey.GetBigIntL(KRsaKeyParameterNUid);

    78 	TCrypto::IsAsymmetricWeakEnoughL(N.BitCount());

    79 	CAsymmetricCipherImpl::ConstructL(aKey);

    80 	

    81 	if (! IsValidKeyLengthL(N.ByteCount()))

    82 		{

    83 		User::Leave(KErrKeySize);

    84 		}

    85 	}

    86 	

    87 CExtendedCharacteristics* CRSAImpl::CreateExtendedCharacteristicsL()

    88 	{

    89 	// All Symbian software plug-ins have unlimited concurrency, cannot be reserved

    90 	// for exclusive use and are not CERTIFIED to be standards compliant.

    91 	return CExtendedCharacteristics::NewL(KMaxTInt, EFalse);

    92 	}

    93 	

    94 const CExtendedCharacteristics* CRSAImpl::GetExtendedCharacteristicsL()

    95 	{

    96 	return CRSAImpl::CreateExtendedCharacteristicsL();

    97 	}

    98 

    99 TUid CRSAImpl::ImplementationUid() const

   100 	{

   101 	return KCryptoPluginRsaCipherUid;

   102 	}

   103 	

   104 void CRSAImpl::EncryptL(const TDesC8& aInput, TDes8& aOutput) const

   105 	{

   106 	__ASSERT_DEBUG(aOutput.MaxLength() >= GetMaximumOutputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

   107 	__ASSERT_DEBUG(aInput.Length() <= GetMaximumInputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicInputTooLarge));

   108 	

   109 	HBufC8* buf = HBufC8::NewLC(GetMaximumOutputLengthL());

   110 	TPtr8 ptr = buf->Des();

   111 	

   112 	iPadding->PadL(aInput, ptr);

   113 	RInteger input = RInteger::NewL(ptr);

   114 	CleanupStack::PushL(input);

   115 	

   116 	RInteger output;

   117 	RSAFunction::EncryptL(*iKey, input, output);

   118 	CleanupStack::PushL(output);

   119 	

   120 	aOutput.Append(*(output.BufferLC()));

   121 	CleanupStack::PopAndDestroy(4, buf); //BufferLC, output, input, buf

   122 	}

   123 

   124 void CRSAImpl::DecryptL(const TDesC8& aInput, TDes8& aOutput) const

   125 	{

   126 	__ASSERT_DEBUG(aOutput.MaxLength() >= GetMaximumOutputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

   127 	__ASSERT_DEBUG(aInput.Length() <= GetMaximumInputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicInputTooLarge));

   128 	

   129 	RInteger input = RInteger::NewL(aInput);

   130 	CleanupStack::PushL(input);

   131 	

   132 	RInteger output;

   133 	

   134 	RSAFunction::DecryptL(*iKey, input, output);

   135 	CleanupStack::PushL(output);

   136 	

   137 	TPtrC8 ptr = *(output.BufferLC());

   138 	iPadding->UnPadL(ptr, aOutput);

   139 	

   140 	CleanupStack::PopAndDestroy(3, &input); //BufferLC(), output, input

   141 	}

   142 

   143 void CRSAImpl::ProcessL(const TDesC8& aInput, TDes8& aOutput)

   144 	{

   145 	if (iCryptoMode.iUid == KCryptoModeEncrypt)

   146 		{

   147 		EncryptL(aInput, aOutput);

   148 		}

   149 	else

   150 		{

   151 		DecryptL(aInput, aOutput);

   152 		}

   153 	}

   154 

   155 TBool CRSAImpl::IsValidKeyLengthL(TInt aKeyBytes) const

   156 	{

   157 	if (aKeyBytes < 1)

   158 		return EFalse;

   159 	

   160 	switch (iCryptoMode.iUid)

   161 		{

   162 		case KCryptoModeEncrypt:

   163 			// Check if GetMaximumInputLengthL() makes sense,

   164 			// if not the key length must be too small

   165 			if (GetMaximumInputLengthL() <= 0)

   166 				return EFalse;

   167 			break;

   168 		

   169 		case KCryptoModeDecrypt:

   170 			// Check if GetMaximumOutputLengthL() makes sense,

   171 			// if not the key length must be too small

   172 			if (GetMaximumOutputLengthL() <= 0)

   173 				return EFalse;

   174 			break;

   175 		}

   176 	return ETrue;

   177 	}

   178