public static void Initialize(string inputFilePath, string outputFilePath, byte[] keyEncryptionKey)
{
byte[] dataEncryptionKey = new byte[Constants.EncryptionKeyLength];
try
{
byte[] encryptedHeader = FileHeaders.ReadEncryptedHeader(inputFilePath);
byte[] nonce = FileHeaders.ReadNonce(inputFilePath);
byte[] header = DecryptFileHeader(inputFilePath, encryptedHeader, nonce, keyEncryptionKey);
if (header == null)
{
throw new ArgumentException("Incorrect password/keyfile or this file has been tampered with.");
}
ChunkHandling.ValidateKeyCommitmentBlock(header);
int lastChunkLength = FileHeaders.GetLastChunkLength(header);
int fileNameLength = FileHeaders.GetFileNameLength(header);
dataEncryptionKey = FileHeaders.GetDataEncryptionKey(header);
Utilities.ZeroArray(header);
using (var inputFile = new FileStream(inputFilePath, FileMode.Open, FileAccess.Read, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.SequentialScan))
using (var outputFile = new FileStream(outputFilePath, FileMode.Create, FileAccess.ReadWrite, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.SequentialScan))
{
nonce = Sodium.Utilities.Increment(nonce);
byte[] additionalData = ChunkHandling.GetPreviousPoly1305Tag(encryptedHeader);
Decrypt(inputFile, outputFile, nonce, dataEncryptionKey, additionalData, lastChunkLength);
}
Finalize(inputFilePath, outputFilePath, fileNameLength);
}
catch (Exception ex) when(ExceptionFilters.Cryptography(ex))
{
Utilities.ZeroArray(dataEncryptionKey);
throw;
}
}
private static byte[] EncryptFileHeader(string inputFilePath, byte[] ephemeralPublicKey, byte[] dataEncryptionKey, byte[] nonce, byte[] keyEncryptionKey)
{
long fileLength = FileHandling.GetFileLength(inputFilePath);
byte[] lastChunkLength = BitConversion.GetBytes(Convert.ToInt32(fileLength % Constants.FileChunkSize));
byte[] fileNameLength = FileHeaders.GetFileNameLength(inputFilePath);
byte[] fileHeader = Arrays.Concat(lastChunkLength, fileNameLength, dataEncryptionKey);
byte[] additionalData = HeaderEncryption.ComputeAdditionalData(fileLength, ephemeralPublicKey);
return(HeaderEncryption.Encrypt(fileHeader, nonce, keyEncryptionKey, additionalData));
}
private static byte[] EncryptFileHeader(string inputFilePath, byte[] dataEncryptionKey, byte[] nonce, byte[] keyEncryptionKey)
{
byte[] keyCommitmentBlock = ChunkHandling.GetKeyCommitmentBlock();
long fileLength = FileHandling.GetFileLength(inputFilePath);
byte[] lastChunkLength = BitConverter.GetBytes(Convert.ToInt32(fileLength % Constants.FileChunkSize));
byte[] fileNameLength = FileHeaders.GetFileNameLength(inputFilePath);
byte[] fileHeader = Utilities.ConcatArrays(keyCommitmentBlock, lastChunkLength, fileNameLength, dataEncryptionKey);
byte[] additionalData = HeaderEncryption.ComputeAdditionalData(fileLength);
return(HeaderEncryption.Encrypt(fileHeader, nonce, keyEncryptionKey, additionalData));
}
public static void Initialize(FileStream inputFile, string outputFilePath, byte[] ephemeralPublicKey, byte[] keyEncryptionKey)
{
var dataEncryptionKey = new byte[Constants.EncryptionKeyLength];
try
{
byte[] encryptedHeader = FileHeaders.ReadEncryptedHeader(inputFile);
byte[] nonce = FileHeaders.ReadNonce(inputFile);
byte[] header = DecryptFileHeader(inputFile, ephemeralPublicKey, encryptedHeader, nonce, keyEncryptionKey);
if (header == null)
{
throw new ArgumentException("Incorrect password/key or this file has been tampered with.");
}
int lastChunkLength = FileHeaders.GetLastChunkLength(header);
int fileNameLength = FileHeaders.GetFileNameLength(header);
dataEncryptionKey = FileHeaders.GetDataEncryptionKey(header);
CryptographicOperations.ZeroMemory(header);
using (var outputFile = new FileStream(outputFilePath, FileMode.Create, FileAccess.ReadWrite, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.SequentialScan))
{
nonce = Utilities.Increment(nonce);
byte[] additionalData = ChunkHandling.GetPreviousTag(encryptedHeader);
Decrypt(inputFile, outputFile, nonce, dataEncryptionKey, additionalData, lastChunkLength);
}
string inputFilePath = inputFile.Name;
inputFile.Dispose();
Finalize(inputFilePath, outputFilePath, fileNameLength);
}
catch (Exception ex) when(ExceptionFilters.Cryptography(ex))
{
CryptographicOperations.ZeroMemory(dataEncryptionKey);
if (!(ex is ArgumentException))
{
FileHandling.DeleteFile(outputFilePath);
}
throw;
}
}