/// <summary> Decrypts./ </summary>
///
/// auto secret = priv.get_shared_secret(pub);
/// auto nonce_plus_secret = fc::sha512::hash(fc::to_string(nonce) + secret.str());
/// auto plain_text = fc::aes_decrypt( nonce_plus_secret, message );
/// auto result = memo_message::deserialize(string(plain_text.begin(), plain_text.end()));
/// FC_ASSERT( result.checksum == uint32_t(digest_type::hash(result.text)._hash[0]) );
/// return result.text;
///
/// <remarks> Paul, 26/10/2015. </remarks>
///
/// <param name="memo"> The memo. </param>
/// <param name="receiverPrivateKey"> The receiver private key. </param>
/// <param name="senderPublicKey"> The sender public key. </param>
///
/// <returns> A string. </returns>
static public string Decrypt(GrapheneMemo memo, KeyPair receiverKeyPair)
{
PublicKey pub = new BitsharesPubKey(memo.from).GetBitcoinPubKey();
byte[] sharedSecret = GetSharedSecret(receiverKeyPair, pub);
string ss = StringExtensions.ByteArrayToHexString(sharedSecret, true);
string ps = memo.nonce.ToString() + StringExtensions.ByteArrayToHexString(Crypto.ComputeSha512(sharedSecret), true);
byte[] seed = ASCIIEncoding.ASCII.GetBytes(ps);
string hex = StringExtensions.ByteArrayToHexString(Crypto.ComputeSha512(seed), true);
string key = hex.Substring(0, 64);
string iv = hex.Substring(64, 32);
byte[] data = Util.HexStringToBytes(memo.message);
int len = AES.AesDecrypt(data, Util.HexStringToBytes(key), Util.HexStringToBytes(iv));
byte[] result = new byte[len - 4];
Buffer.BlockCopy(data, 4, result, 0, result.Length);
string message = UTF8Encoding.UTF8.GetString(result);
return(message);
}
/// <summary> Decrypts./ </summary>
///
/// auto secret = priv.get_shared_secret(pub);
/// auto nonce_plus_secret = fc::sha512::hash(fc::to_string(nonce) + secret.str());
/// auto plain_text = fc::aes_decrypt( nonce_plus_secret, message );
/// auto result = memo_message::deserialize(string(plain_text.begin(), plain_text.end()));
/// FC_ASSERT( result.checksum == uint32_t(digest_type::hash(result.text)._hash[0]) );
/// return result.text;
///
/// <remarks> Paul, 26/10/2015. </remarks>
///
/// <param name="memo"> The memo. </param>
/// <param name="receiverPrivateKey"> The receiver private key. </param>
/// <param name="senderPublicKey"> The sender public key. </param>
///
/// <returns> A string. </returns>
public static string Decrypt(GrapheneMemo memo, KeyPair receiverKeyPair)
{
PublicKey pub = new BitsharesPubKey(memo.from).GetBitcoinPubKey();
byte[] sharedSecret = GetSharedSecret(receiverKeyPair, pub);
string ss = StringExtensions.ByteArrayToHexString(sharedSecret, true);
string ps = memo.nonce.ToString() + StringExtensions.ByteArrayToHexString(Crypto.ComputeSha512( sharedSecret), true);
byte[] seed = ASCIIEncoding.ASCII.GetBytes(ps);
string hex = StringExtensions.ByteArrayToHexString(Crypto.ComputeSha512(seed), true);
string key = hex.Substring(0, 64);
string iv = hex.Substring(64, 32);
byte[] data = Util.HexStringToBytes(memo.message);
int len = AES.AesDecrypt(data, Util.HexStringToBytes(key), Util.HexStringToBytes(iv));
byte[] result = new byte[len - 4];
Buffer.BlockCopy(data, 4, result, 0, result.Length);
string message = UTF8Encoding.UTF8.GetString(result);
return message;
}