prajaybasu/OneTimePassword

A .NET Core client library to generate RFC 4226 (HOTP) and RFC 6238(TOTP) based one time passwords and parse a Google Authenticator based Uri to a serializable account. This library does not handle server side validation or random secret generation..

OneTimePassword

RFC 4226 (HOTP) and RFC 6238 (TOTP) implementation for .NET, also supports parsing Key Uri Format for Google Authenticator Uris and Steam's custom TOTP implementation.

This library does not include server side validation logic, however you can implement your own logic using this library according to your security requirements.

Installation

Install-Package OneTimePassword

Usage examples

From Uri

AuthenticatorAccount.TryParse("otpauth://totp/ACME%20Co:john.doe@email.com?secret=HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ&issuer=ACME%20Co&algorithm=SHA1&digits=6&period=30", out var account); 
var password = account.GeneratePassword().Password;

From custom parameters

using (var hmac = HMAC.Create("HMACSHA1"))
{
    var length = 6;
    var time = DateTimeOffset.Now;
    var period = TimeSpan.FromSeconds(30);
    var secret = Encoding.ASCII.GetBytes("12345678901234567890");
    var password = new TimeBasedAuthenticator().GeneratePassword(length, hmac, secret, time, period).Password;
}

License

Copyright 2019 Prajay Basu

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.