private static void UsingPublicKey(string inputFilePath, byte[] sharedSecret, byte[] recipientPrivateKey)
{
try
{
bool fileIsDirectory = FileHandling.IsDirectory(inputFilePath);
if (fileIsDirectory)
{
DirectoryDecryption.UsingPublicKey(inputFilePath, sharedSecret, recipientPrivateKey);
return;
}
using var inputFile = new FileStream(inputFilePath, FileMode.Open, FileAccess.Read, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.RandomAccess);
byte[] ephemeralPublicKey = FileHeaders.ReadEphemeralPublicKey(inputFile);
byte[] ephemeralSharedSecret = KeyExchange.GetSharedSecret(recipientPrivateKey, ephemeralPublicKey);
byte[] salt = FileHeaders.ReadSalt(inputFile);
byte[] keyEncryptionKey = Generate.KeyEncryptionKey(sharedSecret, ephemeralSharedSecret, salt);
string outputFilePath = GetOutputFilePath(inputFilePath);
DecryptFile.Initialize(inputFile, outputFilePath, ephemeralPublicKey, keyEncryptionKey);
CryptographicOperations.ZeroMemory(keyEncryptionKey);
DecryptionSuccessful(inputFilePath, outputFilePath);
}
catch (Exception ex) when(ExceptionFilters.Cryptography(ex))
{
FileException(inputFilePath, ex);
}
}
private static void DecryptEachFileWithPrivateKey(string[] filePaths, byte[] privateKey)
{
foreach (string inputFilePath in filePaths)
{
bool validFilePath = FilePathValidation.FileDecryption(inputFilePath);
if (!validFilePath)
{
--Globals.TotalCount;
continue;
}
try
{
using var inputFile = new FileStream(inputFilePath, FileMode.Open, FileAccess.Read, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.RandomAccess);
byte[] ephemeralPublicKey = FileHeaders.ReadEphemeralPublicKey(inputFile);
byte[] ephemeralSharedSecret = KeyExchange.GetSharedSecret(privateKey, ephemeralPublicKey);
byte[] salt = FileHeaders.ReadSalt(inputFile);
byte[] keyEncryptionKey = Generate.KeyEncryptionKey(ephemeralSharedSecret, salt);
DecryptInputFile(inputFile, ephemeralPublicKey, keyEncryptionKey);
CryptographicOperations.ZeroMemory(keyEncryptionKey);
}
catch (Exception ex) when(ExceptionFilters.Cryptography(ex))
{
FileException(inputFilePath, ex);
}
}
}
public static byte[] GetAdditionalData(FileStream inputFile, byte[] ephemeralPublicKey)
{
byte[] ciphertextLength = BitConversion.GetBytes(inputFile.Length - Constants.FileHeadersLength);
byte[] magicBytes = FileHeaders.ReadMagicBytes(inputFile);
byte[] formatVersion = FileHeaders.ReadFileFormatVersion(inputFile);
FileHeaders.ValidateFormatVersion(formatVersion, Constants.EncryptionVersion);
return(Arrays.Concat(ciphertextLength, magicBytes, formatVersion, ephemeralPublicKey));
}
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 byte[] GetAdditionalData(string inputFilePath)
{
byte[] magicBytes = FileHeaders.ReadMagicBytes(inputFilePath);
byte[] formatVersion = FileHeaders.ReadFileFormatVersion(inputFilePath);
FileHeaders.ValidateFormatVersion(inputFilePath, formatVersion, Constants.EncryptionVersion);
long fileLength = FileHandling.GetFileLength(inputFilePath);
int headersLength = FileHeaders.GetHeadersLength();
byte[] ciphertextLength = BitConverter.GetBytes(fileLength - headersLength);
return(Utilities.ConcatArrays(magicBytes, formatVersion, ciphertextLength));
}
public static bool?IsKryptorFile(string filePath)
{
try
{
byte[] magicBytes = FileHeaders.ReadMagicBytes(filePath);
return(Utilities.Compare(magicBytes, Constants.KryptorMagicBytes));
}
catch (Exception ex) when(ExceptionFilters.FileAccess(ex))
{
return(null);
}
}
private static void DecryptEachFileWithPrivateKey(string[] filePaths, byte[] privateKey)
{
foreach (string inputFilePath in filePaths)
{
bool validFilePath = FilePathValidation.FileDecryption(inputFilePath);
if (!validFilePath)
{
--Globals.TotalCount;
continue;
}
byte[] ephemeralPublicKey = FileHeaders.ReadEphemeralPublicKey(inputFilePath);
byte[] ephemeralSharedSecret = KeyExchange.GetSharedSecret(privateKey, ephemeralPublicKey);
byte[] salt = FileHeaders.ReadSalt(inputFilePath);
byte[] keyEncryptionKey = Generate.KeyEncryptionKey(ephemeralSharedSecret, salt);
DecryptInputFile(inputFilePath, keyEncryptionKey);
Utilities.ZeroArray(keyEncryptionKey);
}
}
private static void Decrypt(FileStream inputFile, FileStream outputFile, byte[] nonce, byte[] dataEncryptionKey, byte[] additionalData, int lastChunkLength)
{
int headersLength = FileHeaders.GetHeadersLength();
inputFile.Seek(headersLength, SeekOrigin.Begin);
const int offset = 0;
byte[] ciphertextChunk = new byte[Constants.TotalChunkLength];
while (inputFile.Read(ciphertextChunk, offset, ciphertextChunk.Length) > 0)
{
byte[] plaintextChunk = SecretAeadXChaCha20Poly1305.Decrypt(ciphertextChunk, nonce, dataEncryptionKey, additionalData);
ChunkHandling.ValidateKeyCommitmentBlock(plaintextChunk);
nonce = Sodium.Utilities.Increment(nonce);
additionalData = ChunkHandling.GetPreviousPoly1305Tag(ciphertextChunk);
plaintextChunk = ChunkHandling.RemoveKeyCommitmentBlock(plaintextChunk);
outputFile.Write(plaintextChunk, offset, plaintextChunk.Length);
}
outputFile.SetLength((outputFile.Length - Constants.FileChunkSize) + lastChunkLength);
Utilities.ZeroArray(dataEncryptionKey);
}
public static bool VerifySignature(string signatureFilePath, string filePath, byte[] publicKey, out string comment)
{
using var signatureFile = new FileStream(signatureFilePath, FileMode.Open, FileAccess.Read, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.SequentialScan);
byte[] magicBytes = GetMagicBytes(signatureFile);
byte[] formatVersion = GetFormatVersion(signatureFile);
FileHeaders.ValidateFormatVersion(formatVersion, Constants.SignatureVersion);
byte[] preHashed = GetPreHashedHeader(signatureFile);
byte[] fileSignature = GetFileSignature(signatureFile);
byte[] commentBytes = GetCommentBytes(signatureFile);
byte[] signatureFileBytes = Arrays.Concat(magicBytes, formatVersion, preHashed, fileSignature, commentBytes);
bool validGlobalSignature = VerifyGlobalSignature(signatureFile, signatureFileBytes, publicKey);
if (!validGlobalSignature)
{
comment = string.Empty;
return(false);
}
bool preHash = BitConverter.ToBoolean(preHashed);
byte[] fileBytes = GetFileBytes(filePath, preHash);
comment = Encoding.UTF8.GetString(commentBytes);
return(PublicKeyAuth.VerifyDetached(fileSignature, fileBytes, publicKey));
}
public static bool VerifySignature(string signatureFilePath, string filePath, byte[] publicKey)
{
using var signatureFile = new FileStream(signatureFilePath, FileMode.Open, FileAccess.Read, FileShare.Read, Constants.FileStreamBufferSize, FileOptions.RandomAccess);
// Verify the global signature
byte[] magicBytes = GetMagicBytes(signatureFile);
byte[] formatVersion = GetFormatVersion(signatureFile);
FileHeaders.ValidateFormatVersion(signatureFilePath, formatVersion, Constants.SignatureVersion);
byte[] preHashedHeader = GetPreHashedHeader(signatureFile);
byte[] fileSignature = GetFileSignature(signatureFile);
_commentBytes = GetCommentBytes(signatureFile);
byte[] signatureFileBytes = Utilities.ConcatArrays(magicBytes, formatVersion, preHashedHeader, fileSignature, _commentBytes);
bool validGlobalSignature = VerifyGlobalSignature(signatureFile, signatureFileBytes, publicKey);
if (!validGlobalSignature)
{
return(false);
}
// Verify the file signature
bool preHashed = BitConverter.ToBoolean(preHashedHeader);
byte[] fileBytes = GetFileBytes(filePath, preHashed);
return(PublicKeyAuth.VerifyDetached(fileSignature, fileBytes, publicKey));
}
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;
}
}
public static void Initialize(string inputFilePath, string outputFilePath, byte[] ephemeralPublicKey, byte[] salt, byte[] keyEncryptionKey)
{
byte[] dataEncryptionKey = Generate.DataEncryptionKey();
try
{
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))
{
byte[] nonce = Generate.Nonce();
byte[] encryptedHeader = EncryptFileHeader(inputFilePath, dataEncryptionKey, nonce, keyEncryptionKey);
FileHeaders.WriteHeaders(outputFile, ephemeralPublicKey, salt, nonce, encryptedHeader);
nonce = Sodium.Utilities.Increment(nonce);
byte[] additionalData = ChunkHandling.GetPreviousPoly1305Tag(encryptedHeader);
Encrypt(inputFile, outputFile, nonce, dataEncryptionKey, additionalData);
}
Finalize(inputFilePath, outputFilePath);
}
catch (Exception ex) when(ExceptionFilters.Cryptography(ex))
{
FileHandling.DeleteFile(outputFilePath);
Utilities.ZeroArray(dataEncryptionKey);
throw;
}
}
