private byte[] EncryptDataFile(byte[] fileBytes)
{
byte[] encryptedBytes;
switch (Settings.Default.DataFileCryption)
{
case CryptoChoices.OneTimePad:
OneTimePadCrypter otp = new OneTimePadCrypter(Encoding.UTF8.GetBytes(Settings.Default.CryptionDataKey));
encryptedBytes = otp.Encrypt(fileBytes);
break;
case CryptoChoices.TEA:
TEACrypter tea = new TEACrypter(Encoding.UTF8.GetBytes(Settings.Default.CryptionDataKey));
if (TEACrypter.CheckIfDataNeedsPadding(fileBytes))
{
fileBytes = TEACrypter.PadData(fileBytes);
Settings.Default.DataFilePadded = true;
Settings.Default.Save();
}
encryptedBytes = tea.Encrypt(fileBytes);
break;
default:
throw new InvalidOperationException("Cryption settings are not valid: Desired cryption algorithm doesn't exist.");
}
return(encryptedBytes);
}
internal byte[] DecryptFileExplicit(byte[] encryptedBytes, CryptoChoice settings)
{
byte[] fileBytes;
switch (settings.Choice)
{
case CryptoChoices.OneTimePad:
OneTimePadCrypter otp = new OneTimePadCrypter(settings.Key);
fileBytes = otp.Decrypt(encryptedBytes);
break;
case CryptoChoices.TEA:
TEACrypter tea = new TEACrypter(settings.Key);
fileBytes = tea.Decrypt(encryptedBytes);
if (settings.Depad)
{
fileBytes = TEACrypter.DepadData(fileBytes);
}
break;
default:
throw new InvalidOperationException("Cryption settings are not valid: Desired cryption algorithm doesn't exist.");
}
return(fileBytes);
}
public byte[] EncryptFile(string fileName, byte[] fileBytes, CryptoChoice settings, bool replaceRecordIfConflict = false)
{
if (ReadRecord(fileName) != null)
{
if (replaceRecordIfConflict)
{
RemoveRecord(fileName);
}
else
{
throw new InvalidOperationException("The record for a file with this name already exists. If you want to replace it, pass another bool as an argument to the method.");
}
}
SHA1Hasher sha1 = new SHA1Hasher();
sha1.ComputeHash(fileBytes);
string fileHash = sha1.HashedString;
byte[] encryptedBytes;
switch (settings.Choice)
{
case CryptoChoices.OneTimePad:
OneTimePadCrypter otp = new OneTimePadCrypter(settings.Key);
encryptedBytes = otp.Encrypt(fileBytes);
break;
case CryptoChoices.TEA:
TEACrypter tea = new TEACrypter(settings.Key);
if (TEACrypter.CheckIfDataNeedsPadding(fileBytes))
{
fileBytes = TEACrypter.PadData(fileBytes);
settings.Depad = true;
}
encryptedBytes = tea.Encrypt(fileBytes);
break;
default:
throw new InvalidOperationException("Cryption settings are not valid: Desired cryption algorithm doesn't exist.");
}
AddRecord(fileName, settings, fileHash);
return(encryptedBytes);
}
public byte[] DecryptFile(byte[] encryptedBytes, string fileName)
{
var foundRecord = ReadRecord(fileName);
if (foundRecord == null)
{
throw new ArgumentException("There is no record for this file.");
}
CryptoChoice settings = foundRecord.Item1;
string originalFileHash = foundRecord.Item2;
byte[] fileBytes;
switch (settings.Choice)
{
case CryptoChoices.OneTimePad:
OneTimePadCrypter otp = new OneTimePadCrypter(settings.Key);
fileBytes = otp.Decrypt(encryptedBytes);
break;
case CryptoChoices.TEA:
TEACrypter tea = new TEACrypter(settings.Key);
fileBytes = tea.Decrypt(encryptedBytes);
if (settings.Depad)
{
fileBytes = TEACrypter.DepadData(fileBytes);
}
break;
default:
throw new InvalidOperationException("Cryption settings are not valid: Desired cryption algorithm doesn't exist.");
}
SHA1Hasher sha1 = new SHA1Hasher();
sha1.ComputeHash(fileBytes);
if (originalFileHash != sha1.HashedString)
{
throw new Exception("The hash value of the decrypted file and the original file hash value do not match. Access denied.");
}
return(fileBytes);
}
