Please tell me how you can implement something like this.
There is a database that you access through a web interface. Task: to log in, roughly speaking, "signed" by users if one user wants to send the password to another, then he will not be able to use it. The binding to IP is unrealistic, because dyn. Sending to the client confirmation code text how with a unique code and with a certain client ID (roughly a piece of idnt. session), is also not an option, you can also forward. There's only one option authorization via etoken. But really so paranoid?