public byte[] Encrypt(DiffieHellman otherPerson, string secretMessage)
{
// Common secret created by Diffie Hellman
_aes.Key = _diffieHellman.DeriveKeyMaterial(CngKey.Import(otherPerson.PublicKey, CngKeyBlobFormat.EccPublicBlob));
using (var cipherText = new MemoryStream())
{
using (var cs = new CryptoStream(cipherText, _aes.CreateEncryptor(), CryptoStreamMode.Write))
{
var ciphertextMessage = Encoding.Unicode.GetBytes(secretMessage);
cs.Write(ciphertextMessage, 0, ciphertextMessage.Length);
cs.Close();
}
return(cipherText.ToArray());
}
}
public string Decrypt(DiffieHellman otherPerson, byte[] encryptedMessage)
{
// Common secret created by Diffie Hellman
_aes.Key = _diffieHellman.DeriveKeyMaterial(CngKey.Import(otherPerson.PublicKey, CngKeyBlobFormat.EccPublicBlob));
var backupIV = _aes.IV;
_aes.IV = otherPerson._aes.IV;
using (var plainText = new MemoryStream())
{
using (var cs = new CryptoStream(plainText, _aes.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(encryptedMessage, 0, encryptedMessage.Length);
cs.Close();
}
_aes.IV = backupIV;
return(Encoding.Unicode.GetString(plainText.ToArray()));
}
}