ASP authentication using XOR encryption
This article explains how to control application access by validating the user's login and password against a SQL 2000 database. Once validated, the user gets a one time pad Access Code generated by SQL 2000 server, which is different and unique for every login - Access Code changes on every user login - it is one time pad - OTP. Then the user's IP host address is encrypted using Access Code and simple XOR and saved in database (XOR-based OTPs are perfectly secure against cipher text-only cryptanalysis).
On all restricted pages we include the access validation routine and if the user's IP does not match against the saved one, the user does not get access. None of the asp pages use sessions or cookies for communication.
By Valko Yotov at ASP 101.
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