/*

 * Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).

 * All rights reserved.

 * This component and the accompanying materials are made available

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

 * which accompanies this distribution, and is available

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

 *

 * Initial Contributors:

 * Nokia Corporation - initial contribution.

 *

 * Contributors:

 *

 * Description: 

 *

 */

 #include "pkcs7encrypteddataobject.h"

 /** The last character in the PKCS7 EncryptedData OID */

 const TInt KPkcs7EncryptedData = 6;

 EXPORT_C CPKCS7EncryptedDataObject* CPKCS7EncryptedDataObject::NewL(const CPKCS7ContentInfo& aContentInfo)

 	{

 	CPKCS7EncryptedDataObject* self = new (ELeave) CPKCS7EncryptedDataObject();

 	CleanupStack::PushL(self);

 	self->ConstructL(aContentInfo);

 	CleanupStack::Pop(self);

 	return self;	

 	}

 CPKCS7EncryptedDataObject::CPKCS7EncryptedDataObject(void)

 	{

 	}

 CPKCS7EncryptedDataObject::~CPKCS7EncryptedDataObject()

 	{

 	delete iEncryptParams;

 	}

 EXPORT_C TInt CPKCS7EncryptedDataObject::Version() const

 	{

 	return iVersion;

 	}

 EXPORT_C CPKCS7EncryptedDataObject::TContentType CPKCS7EncryptedDataObject::ContentType() const

 	{

 	return iContentType;

 	}

 EXPORT_C const TDesC8& CPKCS7EncryptedDataObject::EncryptedContentInfoData() const

 	{

 	return iEncryptedContent;

 	}	

 EXPORT_C const CPBEncryptParms& CPKCS7EncryptedDataObject::EncryptParams() const

 	{

 	return *iEncryptParams;

 	}

 CPBEncryptParms* CPKCS7EncryptedDataObject::DecodeContentEncryptionAlgorithmL(const TDesC8& aBinaryData) const

 	{

 	TASN1DecGeneric seqGen(aBinaryData);

 	seqGen.InitL();

 	if (seqGen.Tag() != EASN1Sequence || seqGen.Class() != EUniversal)

 		{

 		User::Leave(KErrArgument);

 		}

     TPtrC8 theContent(seqGen.Encoding());

     CPBEncryptParms* encryptParams =  TASN1DecPKCS5::DecodeDERL(theContent);

     return encryptParams;

 	}	

 EXPORT_C HBufC8* CPKCS7EncryptedDataObject::DecryptDataL(const TDesC& aPassword) const

 	{

 	CPBEncryptElement* encryptElement;

     HBufC8* pkcs12Pwd = PKCS12KDF::GeneratePasswordLC(aPassword);

     if(iEncryptParams->Kdf() == CPBEncryptParms::EKdfPkcs12)

 		{

 	 	TPtrC8 iv = iEncryptParams->IV();

 	    HBufC8* ivValue = HBufC8::NewMaxLC(iv.Length());

 	    TPtr8 encryptKeyBuf = ivValue->Des();

 	 	switch(iEncryptParams->Cipher())	

 			{

 	 		case ECipherARC4_128:

 	 		case ECipherARC4_40:

 	 			{

 	 	    	//derive only key it is unnecessary to derive an IV for RC4

 	 	    	break;

 	 			}

 			case ECipher3DES_CBC:

 			case ECipher2Key3DES_CBC:

 			case ECipherRC2_CBC_128_16:	 

 			case ECipherRC2_CBC_40_5:	

 				{

 				PKCS12KDF::DeriveKeyL(encryptKeyBuf, PKCS12KDF::EIDByteIV, *pkcs12Pwd, iEncryptParams->Salt(), iEncryptParams->Iterations());

 				iEncryptParams->SetIV(encryptKeyBuf);

 		    	break;

 				}

 			default:

 				{

 		    	User::Leave(KErrNotSupported);

 		    	break;

 				}

 	 		}

 	 	CleanupStack::PopAndDestroy(ivValue);

 		// Create the decryptor	

 		encryptElement = CPBEncryptElement::NewLC(*pkcs12Pwd, *iEncryptParams);

 		}

 	else

 		{

 		TPBPassword password(aPassword);

 		// Create the decryptor	

 		encryptElement = CPBEncryptElement::NewLC(password.Password(), *iEncryptParams);	

 		}

 	CPBDecryptor* decryptor = encryptElement->NewDecryptLC();

 	TPtrC8 encryptedKey(iEncryptedContent);

 	TUint encryptLength = encryptedKey.Length();

 	TUint maxDecryptLength = decryptor->MaxOutputLength(encryptLength);

 	if ( maxDecryptLength <= 0 )

 		{

 		User::Leave(KErrGeneral);		

 		}

 	HBufC8* decryptedContent = HBufC8::NewLC(maxDecryptLength);

 	TPtr8 dcDes(decryptedContent->Des());

 	decryptor->Process(encryptedKey, dcDes);

 	CleanupStack::Pop(decryptedContent);

 	CleanupStack::PopAndDestroy(3, pkcs12Pwd); // pkcs12Pwd, encryptElement, decryptor

    	return decryptedContent;

    	}

  void CPKCS7EncryptedDataObject::ConstructL(const CPKCS7ContentInfo& aContentInfo)

 	{

 	if(aContentInfo.ContentType() != KPkcs7EncryptedData)

 		{

 		User::Leave(KErrArgument);

 		}

 	// EncryptedData SEQUENCE

 	TASN1DecGeneric decGen(aContentInfo.ContentData());

 	decGen.InitL();

 	if(decGen.Tag() != EASN1Sequence || decGen.Class() != EUniversal)

 		{

 	    User::Leave(KErrArgument);

 		}

     TASN1DecSequence seq1;

     CArrayPtrFlat<TASN1DecGeneric>* EncryptedDataContents = seq1.DecodeDERLC(decGen);       					

 	// Both version and encryptedContentInfo should be present

 	if (EncryptedDataContents->Count() != 2)

 		{

 		User::Leave(KErrArgument);

 		}

 	// VERSION

 	// version is the syntax version number. It shall be 0 for this version of the standard

 	const TASN1DecGeneric* EncryptedDataContentsAt0 = EncryptedDataContents->At(0);

 	if(EncryptedDataContentsAt0->Tag() != EASN1Integer || EncryptedDataContentsAt0->Class() != EUniversal)

 		{

 		User::Leave(KErrArgument);

 		}

 	TASN1DecInteger intDecoder;

 	iVersion = intDecoder.DecodeDERShortL(*EncryptedDataContentsAt0);

 	if (iVersion != 0)

 		{

 	    User::Leave(KErrArgument);		

 	    }

     // ENCRYPTED CONTENT INFO a SEQUENCE

     const TASN1DecGeneric* EncryptedDataContentsAt1 = EncryptedDataContents->At(1);

 	if (EncryptedDataContentsAt1->Tag() != EASN1Sequence || EncryptedDataContentsAt1->Class() != EUniversal)

 		{

 	    User::Leave(KErrArgument);

 	    }		               

 	TASN1DecSequence seq2;

     CArrayPtrFlat<TASN1DecGeneric>* EncryptedContentInfo = seq2.DecodeDERLC(*EncryptedDataContentsAt1);       

     // CONTENT TYPE IDENTIFIED BY AN OBJECT IDENTIFIER

 	// Gets the oid

 	TASN1DecObjectIdentifier ContentTypeoidDec;

 	HBufC* contentType = ContentTypeoidDec.DecodeDERL(*EncryptedContentInfo->At(0));

 	if(contentType->Compare(KPkcs7DataOID()) == 0)

 		{

 		iContentType = EPkcs7Data;

 		}

 	else

 		{

 		User::Leave(KErrNotSupported);

 		}

 	delete contentType;	        

 	// CONTENT ENCRYPTION ALGORITHM

 	// Get the Cipher used and the encoded params in it

     iEncryptParams = DecodeContentEncryptionAlgorithmL(EncryptedContentInfo->At(1)->Encoding());

     // ENCRYPTED CONTENT

 	// This is an OPTIONAL field

 	TInt encryptedContentInfoCount = EncryptedContentInfo->Count();

 	if(encryptedContentInfoCount == 3)

 		{

 		TASN1DecGeneric decOctetString(*EncryptedContentInfo->At(2));

 		decOctetString.InitL();

 	    iEncryptedContent.Set(decOctetString.GetContentDER());

 	   	}

 	else if(encryptedContentInfoCount > 3 || encryptedContentInfoCount < 2)

 	    {

 	    User::Leave(KErrArgument);

 	    }

 	else if(encryptedContentInfoCount == 2)

 		{

 		iEncryptedContent.Set(KNullDesC8());

 		}

 	CleanupStack::PopAndDestroy(2, EncryptedDataContents); //EncryptedDataContents, EncryptedContentInfo    	

 	}