private void LoadMetaDataFromFile(string filePath)
{
try
{
int metaSize;
byte[] metaSizeBytes = new byte[4];
FileStream metaSizeStream = new FileStream(filePath, FileMode.Open);
metaSizeStream.Read(metaSizeBytes, 0, 4);
metaSizeStream.Close();
metaSize = BitConverter.ToInt32(metaSizeBytes, 0);
byte[] faesMetaData = new byte[metaSize];
FileStream faesMeta = new FileStream(filePath, FileMode.Open);
faesMeta.Read(faesMetaData, 0, metaSize);
faesMeta.Close();
try
{
if (metaSize < 7)
{
LoadLegacyMetaDataFromFile(filePath);
}
else
{
ushort faesIdentifierSize;
byte[] faesIdentifierSizeBytes = new byte[2];
Array.Copy(faesMetaData, 4, faesIdentifierSizeBytes, 0, 2);
faesIdentifierSize = BitConverter.ToUInt16(faesIdentifierSizeBytes, 0);
byte[] faesIdentifierBytes = new byte[faesIdentifierSize];
Array.Copy(faesMetaData, 6, faesIdentifierBytes, 0, Convert.ToInt32(faesIdentifierSize));
if (CryptUtils.ConvertBytesToString(faesIdentifierBytes) != CryptUtils.GetCryptIdentifier())
{
LoadLegacyMetaDataFromFile(filePath);
}
else
{
InitWithBytes(faesMetaData);
}
}
}
catch (IOException)
{
Logging.Log("File is already open in another program!", Severity.ERROR);
}
catch (Exception)
{
LoadLegacyMetaDataFromFile(filePath);
}
}
catch (Exception)
{
LoadLegacyMetaDataFromFile(filePath);
}
}
/// <summary>
/// Converts variables into easy-to-manage method calls to create a byte array for metadata
/// </summary>
/// <param name="checksumHashType">Type of checksum used to generate the file hash</param>
/// <param name="originalFileHash">File hash of the original file (checksum generated using previous hash type)</param>
/// <param name="passwordHint">A password hint for the password used to encrypt the file</param>
/// <param name="compressionModeUsed">Compression mode used to compress the file</param>
/// <param name="originalFileName">The name of the original file</param>
public DynamicMetadata(Checksums.ChecksumType checksumHashType, byte[] originalFileHash, string passwordHint, string compressionModeUsed, string originalFileName)
{
_faesIdentifier = CryptUtils.ConvertStringToBytes(CryptUtils.GetCryptIdentifier());
_hashType = CryptUtils.ConvertChecksumTypeToBytes(checksumHashType);
_originalFileHash = originalFileHash;
_encryptionTimestamp = BitConverter.GetBytes((long)(DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0)).TotalSeconds);
_passwordHint = CryptUtils.ConvertStringToBytes(passwordHint.TrimEnd('\n', '\r'));
_encryptionVersion = CryptUtils.ConvertStringToBytes(FileAES_Utilities.GetVersion());
_compressionMode = CryptUtils.ConvertStringToBytes(compressionModeUsed);
_originalFileName = CryptUtils.ConvertStringToBytes(originalFileName);
_totalMetadataSize = (4 + 2 + _faesIdentifier.Length + 2 + _hashType.Length + 2 + _originalFileHash.Length + 2 + _encryptionTimestamp.Length + 2 + _passwordHint.Length + 2 + _encryptionVersion.Length + 2 + _compressionMode.Length + 2 + _originalFileName.Length);
}
/// <summary>
/// Checks the metadata to see if the file can be decrypted
/// </summary>
/// <param name="filePath">Path to file (Compatibility)</param>
/// <returns>If the file can be decrypted</returns>
public bool IsDecryptable(string filePath)
{
if (_usingCompatibilityMode)
{
return(new LegacyCrypt().IsDecryptable(filePath));
}
else if (_dynamicMetadata.GetFaesIdentifier() == CryptUtils.GetCryptIdentifier())
{
return(true);
}
else
{
return(false);
}
}