Text Message Code for access validation

Hi guys,

I am looking for the best approch to validate authentication

Explain:

I would like to validate the computer (OS) that the user is using to login to the site and it is the first time login the site from such computer to pop a message "The computer you are accessing the site is not registered, please check your email and enter the code to authenticate this computer" prompt the user with code entry to validte and then, send either a text message or an email with a random code to be used in the prompting textbox.

What I am looking for is something the banks use to access personal or business account

when the first time accessing the portal it asks for a code sent to either email or text message depending how the user registration.

Hope the above make sense.

Any sample C# code would be very much appreciated

Thanks

To solve this,

1) you have keep a login history table say login_history (table Name).

2) Each time whenever the User Login into the system, the table should be Updated or Inserted (i.e.) Login and Logout Time and Date Should be Updated and Inserted.

3) In the Login History table, Keep a column for Computer OS, Browser.

4) While Login into the System, Get the Current Browser in which the User Log's In and OS too. Update the values into the History Table.

5) When next time when the same User Log's In, Check already the Browser and OS is registered for the same User. In SQL Side.

6) Get the Result in a bool and based on the value, display the Message.

Eg of Checking SQL

select count(1) from login_history where OS=@os and BROWSER=@browser and USERID=@user_id

Hope this may help you. Thanks in Advance.