/**

	@page secure_stream_example_code Secure stream example code

	This example covers: 

	-# @ref stream_example_1 "Encrypting some data with a password and writing it to a file"

	-# @ref stream_example_2 "Reading the data back from the file and decrypting it with the same password".

	Also, see:

	- @ref pbe_example_code

	- @ref secure_store_example_code

<hr>

	@ref secure_stream_example_code_support "Supporting code for this example"

@anchor stream_example_1

@code

/*

 * Encrypt data with password and write it to a file.

 */

void CSecureStreamExample::WriteEncryptedDataL(const TDesC8& aInput, const TDesC& aFilename, const TDesC& aPassword)

		 {

		 // Open a stream to the output file

		 RFileWriteStream writeStream;

		 User::LeaveIfError(writeStream.Replace(iFs, aFilename, EFileShareExclusive | EFileWrite));

		 CleanupClosePushL(writeStream);

		 // Create a CPBEncryptElement object, passing details of the encryption we

		 // are using and the user's password

		 CPBEncryptElement* encryption = CPBEncryptElement::NewLC(aPassword, ECipherDES_CBC);

		 // Store encryption data as the first thing in the stream

		 writeStream << encryption->EncryptionData();

		 // Create an REncryptStream - this wraps the write stream and encrypts

		 // everything written to it

		 REncryptStream encStream;

		 encStream.OpenL(writeStream, *encryption);

		 CleanupClosePushL(encStream);

		 // Now we can simply write the plaintext to the encrypt stream - it gets

		 // encrypted automatically

		 encStream << aInput;

		 // Commit the stream

		 encStream.CommitL();

		 // Free memory (writeStream, encryption, encStream)

		 CleanupStack::PopAndDestroy(3, &writeStream);

		 }

@endcode

@anchor stream_example_2

@code

/*

 * Read data from file and decrypt it.

 */

HBufC8* CSecureStreamExample::ReadEncryptedDataLC(const TDesC& aFilename, const TDesC& aPassword)

		 {

		 // Open a stream to the input file

		 RFileReadStream readStream;

		 User::LeaveIfError(readStream.Open(iFs, aFilename, EFileRead));

		 CleanupClosePushL(readStream);

		 // Read the encryption data from the stream

		 CPBEncryptionData* encryptionData = CPBEncryptionData::NewLC(readStream);

		 // Recreate the CPBEncryptElement object, using the encryption data from the

		 // file and the user's password

		 CPBEncryptElement* encryption = CPBEncryptElement::NewLC(*encryptionData, aPassword);

		 // Create an RDecryptStream based on the read stream - this decrypts

		 // everything we read from it

		 RDecryptStream decStream;

		 decStream.OpenL(readStream, *encryption);

		 CleanupClosePushL(decStream);

		 // Now we can read the plaintext straight from the stream

		 HBufC8* plaintext = HBufC8::NewL(decStream, KMaxTInt);

		 // Free memory (readStream, encryptionData, encryption, decStream)

		 CleanupStack::PopAndDestroy(4, &readStream);

		 CleanupStack::PushL(plaintext);

		 // Return plaintext to the caller

		 return plaintext;

		 }

@endcode

*/