BasicAdmin - Personal Organizer

#include "StdAfx.h"
#include "Interno.h"
#include "osrng.h"

using namespace std;
using namespace CryptoPP;

void CInterno::InternalEncrypt(RSAES_PKCS1v15_Encryptor* pEncryptor, const unsigned char * pbIn, int nLengthInBytes, unsigned char ** ppbOut)
{
	// Calculate the chunk sizes
	int nMaxMsgLen = pEncryptor->FixedMaxPlaintextLength();
	int nChunks = (nLengthInBytes%nMaxMsgLen) ? nLengthInBytes/nMaxMsgLen+1 : nLengthInBytes/nMaxMsgLen;
	int nCipherLen = pEncryptor->CiphertextLength(nMaxMsgLen);

	int nChunkLen;


	// Allocate more than will be needed
	int nBufferSize = nCipherLen * (nChunks+1);
	byte * pbBuffer = new byte[nBufferSize];
	byte * pbOut = pbBuffer;
	memset(pbOut, 0, nBufferSize);
	int nTotalEncryptedBytes = 0;

	// Encrypt in chunks
	AutoSeededRandomPool rng;
	nLengthOutBytes = 0;
	for(int n=1; n <= nChunks; n++)
	{
		// Find the chunk length
		nChunkLen =  (n == nChunks) ? (nLengthInBytes - (n-1)*nMaxMsgLen) : nMaxMsgLen;

		pEncryptor->Encrypt(rng, ((byte*)pbIn) + (n-1)*nMaxMsgLen, nChunkLen, pbOut);

		// Keep the last length
		pbOut += pEncryptor->CiphertextLength(nChunkLen);
		nLengthOutBytes += pEncryptor->CiphertextLength(nChunkLen);

		//DebugPrint("Chunk %d: (%d bytes)\r\n%s", n, nChunkLen, ToBinaryString(pbBuffer, nLengthOutBytes).c_str());
	}
	//
	// Copy bytes out (caller must deallocate memory, no garbage collection on new!)
	//
	*ppbOut = new unsigned char[nLengthOutBytes];
	memcpy(*ppbOut, pbBuffer, nLengthOutBytes);

	// free buffer
	delete pbBuffer;
}

void CInterno::InternalDecrypt(RSAES_PKCS1v15_Decryptor* pDecryptor, const unsigned char * pbIn, int nLengthInBytes, unsigned char ** ppbOut)
{
	// Find the maximum message length
	int nMaxMsgLen = pDecryptor->FixedCiphertextLength();
	int nChunks = (nLengthInBytes%nMaxMsgLen) ? nLengthInBytes/nMaxMsgLen+1 : nLengthInBytes/nMaxMsgLen;

	int nChunkLen;

	int nBufferSize = pDecryptor->MaxPlaintextLength(nMaxMsgLen) * (nChunks+1);
	byte * pbBuffer = new byte[nBufferSize];
	byte * pbOut = pbBuffer;
	memset(pbOut, 0, nBufferSize);
	int nTotalDecryptedBytes = 0;

	// Decrypt chunks
	AutoSeededRandomPool rng;
	nLengthOutBytes = 0;
	for(int n=1; n <= nChunks; n++)
	{
		nChunkLen =  (n == nChunks) ? (nLengthInBytes - (n-1)*nMaxMsgLen) : nMaxMsgLen;
		unsigned int unLen = pDecryptor->MaxPlaintextLength(nChunkLen);

		size_t nOutputLength = 0;
		nOutputLength = pDecryptor->Decrypt(rng, ((byte*)pbIn) + (n-1)*nMaxMsgLen, nChunkLen, pbOut).messageLength;

		pbOut += nOutputLength;
		nLengthOutBytes += nOutputLength;
	}

	//
	// Copy bytes out (caller must deallocate memory, no garbage collection on new!)
	//
	*ppbOut = new unsigned char[nLengthOutBytes];
	memcpy(*ppbOut, pbBuffer, nLengthOutBytes);

	// free memory
	delete pbBuffer;

}