protected virtual string _AddSalt(string token, TokenSalt salt)
{
token = _Replace(token, 2, salt.VersionPosition.ToString());
// add version
token = _SetVersion(token, salt.VersionPosition);
// add salt
token = _Replace(token, salt.VersionPosition + 1, salt.SaltPosition.ToString("D2"));
token = _Replace(token, salt.SaltPosition, salt.Salt);
// add data and timestamp
token = _Replace(token, salt.VersionPosition + 5, salt.DataLength.ToString("D2"));
token = _Replace(token, salt.VersionPosition + 3, salt.DataPosition.ToString("D2"));
if (!string.IsNullOrEmpty(salt.Data))
{
if (salt.Data.Length > _settings.DataMaxlength - _TIMESTAMP_LENGTH)
{
var message = $"data length is not in range, max length is {_settings.DataMaxlength - _TIMESTAMP_LENGTH}";
throw new ArgumentOutOfRangeException(nameof(salt.Data), message);
}
token = _Replace(token, salt.DataPosition, salt.Data);
}
token = _Replace(token, salt.DataPosition + _settings.DataMaxlength - _TIMESTAMP_LENGTH, salt.Timestamp.ToString("x8"));
// apply backpack
return(_backpack.Encode(token));
}
public string Encrypt(string input, string key, string data = null)
{
var versionPosition = _Random.Next(_settings.VersionPosStart, _settings.VersionPosEnd - _settings.VersionLength);
var saltPosition = _Random.Next(_settings.SaltPosStart, _settings.SaltPosEnd - _settings.SaltLength);
var dataPosition = _Random.Next(_settings.DataPosStart, _settings.DataPosEnd - _settings.DataMaxlength);
var timestamp = DateTime.Now.ToTimestamp();
var salt = new TokenSalt(_GenerateSalt(), data, timestamp, versionPosition, saltPosition, dataPosition, data?.Length ?? 0);
return(Encrypt(input, key, salt));
}
public string Encrypt(string input, string key, TokenSalt salt)
{
var keyBuffer = Encoding.UTF8.GetBytes(key + salt.Salt);
using (var sha = IncrementalHash.CreateHMAC(_settings.HashAlgorithm, keyBuffer))
{
sha.AppendData(Encoding.UTF8.GetBytes(input));
var buffer = sha.GetHashAndReset();
var token = BitConverter.ToString(buffer).Replace("-", string.Empty).ToLower();
return(_AddSalt(token, salt));
}
}
