Controlling group access to doors
An entity controlling access of a plurality of users to at least one disconnected door includes mapping the plurality of users to a group, for each time interval d of a sequence of dates, having an authority produce a digital signature indicating that members of the group can access door during time interval d, causing at least one of the members of the group to receive the digital signature during time interval d for presentation to the door in order to pass therethrough, having the at least one member of the group present the digital signature to the door D, and having the door open after verifying that (i) the digital signature is a digital signature of the authority indicating that members of the group can access the door at time interval d, and (ii) that the current time is within time interval d. The at least one member of the group may have a user card and the door may have a card reader coupled to an electromechanical lock, and the at least one member of the group may receive the digital signature by storing it into the user card, and may present the digital signature to the door by having the user card read by the card reader.
1. A method of controlling physical access, comprising:
providing real time credentials to a group of users;
reviewing, using at least one processor, the real time credentials, wherein the real time credentials include a first part that is unchanged over a period of time and a second part that is modified on a periodic basis over the period of time, wherein the second part provides a proof that the real time credentials are current;
verifying, using at least one processor, validity of the real time credentials by performing a one-way operation on the second part and comparing the result to the first part, wherein at least a portion of the first part of the real time credentials represents a one-way function applied a plurality of times to a portion of the second part of the real time credentials, and wherein the plurality of times that the one-way function is applied to the portion of the second part corresponds to a time that the second part was provided and the period of time; and
allowing physical access to members of the group only if the real time credentials are verified as valid.
2. A method, according to claim 1 , wherein the first part is digitally signed by an authority.
3. A method, according to claim 2 , wherein the authority provides the second part.
4. A method, according to claim 2 , wherein the second part is provided by an entity other than the authority.
5. A method, according to claim 1 , wherein the real time credentials are provided on a smart card.
6. A method, according to claim 1 , wherein members of the group obtain the second part of the real time credentials at a first location.
7. A method, according to claim 6 , wherein members of the group are allowed access to a second location different and separate from the first location.
8. A method, according to claim 1 , wherein the one way function is a one-way hash applied the plurality of times to the portion of the second part of the real time credentials.
9. A method, according to claim 8 , wherein the plurality of times corresponds to an amount of time elapsed since the first part of the real time credentials were issued.
10. A method, according to claim 1 , wherein controlling physical access includes controlling access through a door.