public byte[] WriteData(byte[] sessionKey, byte fileNo, byte dataIn)
{
//byte fileNo = 0x01;
byte[] offset = new byte[] { 0x00, 0x00, 0x00 }; //offset of 0
byte[] length = new byte[] { 0x00, 0x00, 0x01 }; //length of 1
byte[] dataToWrite = new byte[] { dataIn };
byte[] dataForCRC32Header = new byte[] { (byte)DesfireCommand.CommandType.WriteData, fileNo, offset[2], offset[1], offset[0], length[2], length[1], length[0] };
byte[] dataForCRC32 = new byte[dataForCRC32Header.Length + dataToWrite.Length];
Array.Copy(dataForCRC32Header, dataForCRC32, dataForCRC32Header.Length);
Array.Copy(dataToWrite, 0, dataForCRC32, dataForCRC32Header.Length, dataToWrite.Length);
uint crc32 = Crc32.Compute(dataForCRC32);
string dataPlusCRC = Formatting.ByteArrayToHexString(dataToWrite) + Formatting.ByteArrayToHexString(BitConverter.GetBytes(crc32));
byte[] dataPlusCRCPadded = Formatting.HexStringToByteArray(dataPlusCRC);
Formatting.PadToMultipleOf(ref dataPlusCRCPadded, 16);
string initialIV = "00000000000000000000000000000000";
byte[] dataPlusCRCResultPaddedEncrypted = AESCrypto.AESEncrypt(
sessionKey,
Formatting.HexStringToByteArray(initialIV),
dataPlusCRCPadded);
byte[] extractIV = new byte[16];
Array.Copy(dataPlusCRCResultPaddedEncrypted, dataPlusCRCResultPaddedEncrypted.Length - 16, extractIV, 0, 16);
byte[] cmdToSendHeader = new byte[] { fileNo, offset[2], offset[1], offset[0], length[2], length[1], length[0] };
byte[] cmdToSend = new byte[cmdToSendHeader.Length + dataPlusCRCResultPaddedEncrypted.Length];
Array.Copy(cmdToSendHeader, cmdToSend, cmdToSendHeader.Length);
Array.Copy(dataPlusCRCResultPaddedEncrypted, 0, cmdToSend, cmdToSendHeader.Length, dataPlusCRCResultPaddedEncrypted.Length);
DesfireCommand desfireCommand = new DesfireCommand()
{
Command = (byte)DesfireCommand.CommandType.WriteData,
Data = cmdToSend
};
DesfireResponse desfireResFile = SendCommand(desfireCommand) as DesfireResponse;
if (!desfireResFile.Succeeded)
{
throw new DesFireException("Error:" + desfireResFile.SW);
}
byte[] cmac = AESCMAC.CMAC(
sessionKey,
extractIV,
new byte[] { desfireResFile.SW2 });
byte[] updatedIV = cmac;
byte[] data = ReadData(sessionKey, updatedIV, fileNo);
if (data[0] != dataToWrite[0])
{
throw new DesFireException("Data read not the same as data written");
}
return(data);
}
public byte[] ReadData(byte[] sessionKey, byte[] updatedIV, byte fileNo)
{
byte[] offset = new byte[] { 0x00, 0x00, 0x00 }; //offset of 0
byte[] length = new byte[] { 0x00, 0x00, 0x01 }; //length of 1
byte[] dataForCMAC = new byte[] { (byte)DesfireCommand.CommandType.ReadData, fileNo, offset[2], offset[1], offset[0], length[2], length[1], length[0] };
byte[] cmac = AESCMAC.CMAC(
sessionKey,
updatedIV,
dataForCMAC);
updatedIV = cmac;
byte[] cmdToSend = new byte[] { fileNo, offset[2], offset[1], offset[0], length[2], length[1], length[0] };
DesfireCommand desfireCommand = new DesfireCommand()
{
Command = (byte)DesfireCommand.CommandType.ReadData,
Data = cmdToSend
};
DesfireResponse desfireRes = SendCommand(desfireCommand) as DesfireResponse;
if (!desfireRes.Succeeded)
{
throw new DesFireException("Error:" + desfireRes.SW);
}
byte[] dataBytes = AESCrypto.AESDecrypt(
sessionKey,
updatedIV,
desfireRes.ResponseData);
byte[] extractIV = new byte[16];
Array.Copy(desfireRes.ResponseData, desfireRes.ResponseData.Length - 16, extractIV, 0, 16);
int lengthofData = 0x01;
byte[] data = new byte[lengthofData];
Array.Copy(dataBytes, data, data.Length);
byte[] crc = new byte[4];
Array.Copy(dataBytes, data.Length, crc, 0, crc.Length); //crc is 4 bytes long
byte[] dataPlusStatus = new byte[data.Length + 1];
Array.Copy(data, dataPlusStatus, data.Length);
Array.Copy(new byte[] { 0x00 }, 0, dataPlusStatus, data.Length, 1);
uint crc32 = Crc32.Compute(dataPlusStatus);
//compare crc32 to crc
if (BitConverter.ToUInt32(crc, 0) != crc32)
{
throw new DesFireException("CRC32 error");
}
return(data);
}
