private static string GetVersionNumber(byte[] byteStream)
{
var versionNumber = ByteHelpers.CreateSpecialByteArray(2);
Buffer.BlockCopy(byteStream, 0, versionNumber, 0, 2);
var version = $"{versionNumber[0]}.{versionNumber[1]}";
return(version);
}
public byte[] Load(byte[] byteStream)
{
if (byteStream == null)
{
throw new ArgumentNullException(nameof(byteStream));
}
var versionNumber = ByteHelpers.CreateSpecialByteArray(2);
var hash = ByteHelpers.CreateSpecialByteArray(32);
var encrypted = ByteHelpers.CreateSpecialByteArray((byteStream.Length - 34));
SplitFileIntoChunks(byteStream, versionNumber, hash, encrypted);
CheckFileIntegrity(hash, encrypted);
return(DecryptData(encrypted));
}
private static byte[] CheckHmac(byte[] dataToDecrypt, byte[] salt, AesCryptoServiceProvider aes)
{
var hmac = ByteHelpers.CreateSpecialByteArray(32);
var encryptedData = ByteHelpers.CreateSpecialByteArray(dataToDecrypt.Length - 32);
Buffer.BlockCopy(dataToDecrypt, 0, hmac, 0, 32);
Buffer.BlockCopy(dataToDecrypt, 32, encryptedData, 0, dataToDecrypt.Length - 32);
var newHmac = CreateHmac(salt, aes, encryptedData);
if (!ByteHelpers.ByteArrayCompare(hmac, newHmac))
{
throw new CryptographicException("The authenticated message code doesn't match. \n\nThe message may have been corrupted or tampered with.");
}
return(encryptedData);
}
public void CreateSpecialByteArrayCreateArayOfSize10()
{
byte[] array = ByteHelpers.CreateSpecialByteArray(10);
Assert.AreEqual(10, array.Length);
}
public void CreateSpecialByteArrayThrowsInvalidOperationExceptionIfLengthIsZero()
{
ByteHelpers.CreateSpecialByteArray(0);
}