Patent ID: 7536582

Claim:
A method for controlling access by N users to a resource comprising the steps of: receiving from a user a message that requests access to said resource, which message includes a number B obtained by performing a mathematical operation that is related to a number that represents said user and to N; in response to said message, retrieving from a predetermined location associated with said resource a stored value C that is 0 when the resource is available to any user, and other than 0 otherwise; if C indicates said resource is available to be accessed, (a) sending a message to said user that includes a number D=0, and (b) storing B in said predetermined location, thereby replacing C with B; if C indicates said resource is unavailable to be accessed, sending said message to said user with D=C, wherein B=P+T*(N+1), where P is a number representing said user and is not greater than N, T is a number representing a time stamp, and symbol * stands for the multiplication operation.