} //End method
//Implements IEncryptionMachine.Decrypt2
//Main user interface for the FortMachine library.
//This method can be used to decrypt big files as it uses stream based operation for reading and
//writing the data.
//Returns true on success, false on failure.
public bool Decrypt2(string passphrase, string inputpath, string outputpath)
{
FileStream StreamIn = null;
FileStream StreamOut = null;
CryptoStream decrypto = null;
FileStream NewPlainStream = null;
//Make sure our outputpath has correct encoding
//byte[] filenamebytes = Encoding.Default.GetBytes(outputpath);
//outputpath = Encoding.Default.GetString(filenamebytes);
try
{
byte[] key;
byte[] IV;
byte[] salt;
byte[] magic_header;
int BufferSize = 4096;
byte[] buffer = new byte[BufferSize];
int BytesRead;
byte[] IntegrityHash;
IV = new byte[FortMachineConstants.IV_SIZE];
salt = new byte[FortMachineConstants.SALT_SIZE];
magic_header = new byte[FortMachineConstants.MAGIC_HEADER_SIZE];
IntegrityHash = new byte[FortMachineConstants.DATA_INTEGRITY_HASH_SIZE];
StreamIn = new FileStream(inputpath, FileMode.Open, FileAccess.ReadWrite);
StreamOut = new FileStream(outputpath, FileMode.OpenOrCreate, FileAccess.Write);
//Ignore the magic header and move file pointer to the next bytes
StreamIn.Read(magic_header, 0, FortMachineConstants.MAGIC_HEADER_SIZE);
//Read the IV into the buffer
StreamIn.Read(IV, 0, FortMachineConstants.IV_SIZE);
//Read passphrase salt into a buffer
StreamIn.Read(salt, 0, FortMachineConstants.SALT_SIZE);
//Read data integrity hash
StreamIn.Read(IntegrityHash, 0, FortMachineConstants.DATA_INTEGRITY_HASH_SIZE);
key = this.ProcessKeyWithSalt(passphrase, salt);
AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
aes.Key = key;
aes.IV = IV;
aes.Mode = CipherMode.CBC;
decrypto = new CryptoStream(StreamOut, aes.CreateDecryptor(), CryptoStreamMode.Write);
do
{
BytesRead = StreamIn.Read(buffer, 0, BufferSize);
decrypto.Write(buffer, 0, BytesRead);
} while (BytesRead != 0);
decrypto.Close();
StreamIn.Close();
//Create new temporary stream from the decrypted file to verify data integrity
NewPlainStream = new FileStream(outputpath, FileMode.Open, FileAccess.Read);
//Verify data integrity
if (!DataIntegrity.VerifyHash(NewPlainStream, key, IntegrityHash))
{
this._IsDataTampered = true;
}
else
{
this._IsDataTampered = false;
}
NewPlainStream.Close();
File.Delete(inputpath);
}
catch (Exception ex)
{
//Clean up streams, if they where created
if (decrypto != null)
{
decrypto.Close();
}
if (StreamOut != null)
{
StreamOut.Close();
}
if (StreamIn != null)
{
StreamIn.Close();
}
if (NewPlainStream != null)
{
NewPlainStream.Close();
}
//As decryption failed, check if the output file was created and delete it
//because it would be incomplete.
if (File.Exists(outputpath))
{
File.Delete(outputpath);
}
this._LastErrorMessage = "Decryption failed: " + ex.Message;
return(false);
}
return(true);
} //End method
} //End method
//Implements IEncryptionMachine.Encrypt2
//Main user interface for the FortMachine library.
//This method can be used to encrypt big files as stream based operations are used and
//data is not read into memory at once.
public bool Encrypt2(string passphrase, string inputpath, string outputpath, bool KeepPlainFile = false)
{
FileStream StreamIn = null;
FileStream StreamOut = null;
CryptoStream crypto = null;
try
{
byte[] IV;
FortKey key;
byte[] KeyBytes;
int BufferSize = 4096;
byte[] buffer = new byte[BufferSize];
int BytesRead;
byte[] IntegrityHash;
key = this.CreateKey(passphrase);
KeyBytes = key.GetNew();
IV = this.GetRandom16IV();
StreamIn = new FileStream(inputpath, FileMode.Open, FileAccess.Read);
StreamOut = new FileStream(outputpath, FileMode.OpenOrCreate, FileAccess.Write);
IntegrityHash = DataIntegrity.GetHMACHash(StreamIn, KeyBytes);
StreamIn.Seek(0, SeekOrigin.Begin);
//First write our magic header to mark that the file is encrypted with Fort
StreamOut.Write(FortMachineConstants.MAGIC_HEADER, 0, FortMachineConstants.MAGIC_HEADER_SIZE);
//Then, write IV into the file
StreamOut.Write(IV, 0, FortMachineConstants.IV_SIZE);
//Then, write the salt into the file
StreamOut.Write(key.Salt, 0, FortMachineConstants.SALT_SIZE);
//Then, write the integrity has into the file
StreamOut.Write(IntegrityHash, 0, FortMachineConstants.DATA_INTEGRITY_HASH_SIZE);
AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
aes.Key = KeyBytes;
aes.IV = IV;
aes.Mode = CipherMode.CBC;
crypto = new CryptoStream(StreamOut, aes.CreateEncryptor(), CryptoStreamMode.Write);
do
{
BytesRead = StreamIn.Read(buffer, 0, BufferSize);
crypto.Write(buffer, 0, BytesRead);
} while (BytesRead != 0);
crypto.Close();
StreamIn.Close();
if (!KeepPlainFile)
{
File.Delete(inputpath);
}
}
catch (Exception ex)
{
if (crypto != null)
{
crypto.Close();
}
if (StreamIn != null)
{
StreamIn.Close();
}
if (File.Exists(outputpath))
{
File.Delete(outputpath);
}
this._LastErrorMessage = "Encryption failed: " + ex.Message;
return(false);
}
return(true);
} //End method
