title: Extend identity for SMS OTP based login
body: <p>I have trying to implment one time registration verification &amp; daily login using SMS OTP for my app using asp.net core identity implementation.</p>
  <blockquote>
  <p>It is one time token, which should expire in 15 minutes if not used</p>
  <p>User should request it again in case its expired or lost</p>
  </blockquote>
  <p>Searching around for it, all the implementation provide details about MFA or Google Authenticator based verification, where this scenario is slightly different.</p>
  <blockquote>
  <p>The Token will not be generated by the Server, and not the Authenticator app.</p>
  <p>I need to store token along with its genrated at time.</p>
  <p>The token will be 6 digit SMS.</p>
  </blockquote>
  <p>The scenario is more similar to <code>password less auth</code> <a href="https://www.scottbrady91.com/ASPNET-Identity/Implementing-Mediums-Passwordless-Authentication-using-ASPNET-Core-Identity" rel="noreferrer">mentioned here</a>, but then the token in that case is not stored, I need to store it with Validity, not sure how to extend .net core identity to match above requirement.</p>
  <p>This is fairly standard way of phone number authentication</p>
  <p>I know this is not a standard SO format, but I am at loss from where to start</p>