private Stream GetReadMemoryStream(string filePath, string password)
{
var decryptedMemoryStream = new MemoryStream(); //TODO: MemoryStream or temporary decrypted file on disk?
var metadata = EncryptionFactory.GetMetadata();
metadata.Initialize(password);
var fileStream = File.OpenRead(filePath);
if (!metadata.TryReadFromStream(fileStream, Version))
{
decryptedMemoryStream.Close();
fileStream.Seek(0, SeekOrigin.Begin);
return(fileStream);
}
metadata.ComputeAndValidateHmacHash(fileStream);
using (var algorithm = metadata.GetCryptographyAlgorithm())
{
using var transform = algorithm.CreateDecryptor();
using var cryptoStream = new CryptoStreamWrapper(fileStream, transform, CryptoStreamMode.Read);
cryptoStream.CopyTo(decryptedMemoryStream);
cryptoStream.Close();
}
fileStream.Close();
decryptedMemoryStream.Seek(0, SeekOrigin.Begin);
return(decryptedMemoryStream);
}
private void DecryptFile(string filePath, string password)
{
var fileInfo = new FileInfo(filePath);
if (fileInfo.IsReadOnly)
{
fileInfo.IsReadOnly = false;
}
var decryptedFilePath = GetUniqFileName(filePath, ".dec");
try
{
var metadata = EncryptionFactory.GetMetadata();
metadata.Initialize(password);
using (var fileStream = File.OpenRead(filePath))
{
if (!metadata.TryReadFromStream(fileStream, Version))
{
return;
}
metadata.ComputeAndValidateHmacHash(fileStream);
using (var decryptedFileStream = new FileStream(decryptedFilePath, FileMode.Create))
{
using (var algorithm = metadata.GetCryptographyAlgorithm())
{
using (var transform = algorithm.CreateDecryptor())
{
using (var cryptoStream = new CryptoStreamWrapper(decryptedFileStream, transform, CryptoStreamMode.Write))
{
fileStream.CopyTo(cryptoStream);
cryptoStream.FlushFinalBlock();
cryptoStream.Close();
}
}
}
decryptedFileStream.Close();
}
fileStream.Close();
}
ReplaceFile(decryptedFilePath, filePath);
}
catch (Exception exception)
{
if (File.Exists(decryptedFilePath))
{
File.Delete(decryptedFilePath);
}
throw exception;
}
}
private void EncryptFile(string filePath, string password)
{
var fileInfo = new FileInfo(filePath);
if (fileInfo.IsReadOnly)
{
fileInfo.IsReadOnly = false;
}
var ecryptedFilePath = GetUniqFileName(filePath, ".enc");
try
{
var metadata = EncryptionFactory.GetMetadata();
metadata.Initialize(Version, password, fileInfo.Length);
using (var ecryptedFileStream = new FileStream(ecryptedFilePath, FileMode.Create))
{
metadata.WriteToStream(ecryptedFileStream);
using (var algorithm = metadata.GetCryptographyAlgorithm())
{
using var transform = algorithm.CreateEncryptor();
using var cryptoStream = new CryptoStreamWrapper(ecryptedFileStream, transform, CryptoStreamMode.Write);
using (var fileStream = File.OpenRead(filePath))
{
fileStream.CopyTo(cryptoStream);
fileStream.Close();
}
cryptoStream.FlushFinalBlock();
metadata.ComputeAndWriteHmacHash(ecryptedFileStream);
cryptoStream.Close();
}
ecryptedFileStream.Close();
}
ReplaceFile(ecryptedFilePath, filePath);
}
catch (Exception exception)
{
if (File.Exists(ecryptedFilePath))
{
File.Delete(ecryptedFilePath);
}
throw exception;
}
}
