/// <summary>
/// Encrypt the bytes with Shared secret
/// </summary>
/// <param name="inputBytes">Array of the bytes to encrypt</param>
/// <param name="bobAddress">Receiver Neblio Address</param>
/// <param name="secret">Neblio Private Key of the Sender in the form of BitcoinSecret</param>
/// <param name="sharedkey">shared key</param>
/// <returns></returns>
public static async Task <(bool, byte[])> EncryptBytesWithSharedSecret(byte[] inputBytes, string bobAddress, BitcoinSecret secret, string sharedkey = "")
{
if (inputBytes == null || inputBytes.Length == 0)
{
throw new Exception("Input cannot be empty or null.");
}
if (string.IsNullOrEmpty(bobAddress))
{
throw new Exception("Partner Address cannot be empty or null.");
}
if (secret == null)
{
throw new Exception("Input secret cannot null.");
}
(bool, string)key = (false, "");
if (string.IsNullOrEmpty(sharedkey))
{
key = await GetSharedSecret(bobAddress, secret);
if (!key.Item1)
{
return(false, null);
}
}
else
{
key.Item2 = sharedkey;
}
try
{
var ebytes = SymetricProvider.EncryptBytes(key.Item2, inputBytes);
return(true, ebytes);
}
catch (Exception ex)
{
Console.WriteLine("Cannot encrypt bytes. " + ex.Message);
throw new Exception("Cannot encrypt bytes. " + ex.Message);
}
}
/// <summary>
///
/// </summary>
/// <param name="message"></param>
/// <param name="key"></param>
/// <returns></returns>
/// <exception cref="ArgumentNullException"></exception>
public static byte[] EncryptBytesWithPublicKey(byte[] message, PubKey key)
{
if (message is null)
{
throw new ArgumentNullException(nameof(message));
}
var ephemeral = new Key();
var sharedKey = NBitcoin.Crypto.Hashes.SHA512(key.GetSharedPubkey(ephemeral).ToBytes());
var iv = sharedKey.SafeSubarray(0, 16);
var encryptionKey = sharedKey.SafeSubarray(16, 16);
var hashingKey = sharedKey.SafeSubarray(32);
//var aes = new AesBuilder().SetKey(encryptionKey).SetIv(iv).IsUsedForEncryption(true).Build();
//var cipherText = aes.Process(message, 0, message.Length);
var cipherText = SymetricProvider.EncryptBytes(encryptionKey, message, iv);
var ephemeralPubkeyBytes = ephemeral.PubKey.ToBytes();
var encrypted = Encoders.ASCII.DecodeData("BIE1").Concat(ephemeralPubkeyBytes, cipherText);
var hashMAC = HMACSHA256(hashingKey, encrypted);
return(encrypted.Concat(hashMAC));
}