CODEWITHSUNDEEP
asp.net-mvc-4two-factor-authenticationgoogle-authenticator
Haddar Macdasi
Haddar Macdasi

Reputation: 3555

Why Two Factor Authentication GeneratePin the wrong code?

I've implemented the code from http://satalketo.com/2013/09/mvc-two-factor-authentication/ Two Factor Authentication in ASP.NET MVC when user register he gets a Secret Key and shown a QRcode he can scan to Google Authenticator, all works fine and well, accept when the user tries to Log In the system the key always different from the one he enters. function GeneratePin at server side generate different key from that he gets in the Google Authenticator mobile app. I have no idea whats wrong, tried to think maybe time zone isn't correct ,my time zone is Jerusalem UTC + 2

Upvotes: 0

Views: 887

Answers (1)

Sam Jenkins
Sam Jenkins

Reputation: 1314

I've looked through my code a fair bit and I can't see any reason why this should be an issue. The only reason that I can come up with is that one of the two devices is more than 30 seconds out of sync with UTC.

I have updated the source code to include checking against the 30 second periods either side of the current one to try and deal with any situations like that.

You can find the updated code on GitHub, which would be the best place to download the entire solution. My article Two Factor Authentication in ASP.NET MVC has been updated to include the code for checking the period either side.

If this doesn't help please let me know with any additional information you can think of.

Upvotes: 1

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