Cryptography – Cryptanalysis
Patent
1994-06-09
1996-03-05
Cain, David C.
Cryptography
Cryptanalysis
380 16, 380 20, H04N 7167
Patent
active
054974186
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates generally to a system for processing the storage of data and carrying out specific programmes by means of memory cards.
BACKGROUND ART
There are many known data processing systems comprising a set of "memory cards", at least one "administration and processing station" or "unit" and at least one "communications network" for communicating at least one "memory card" with at least one station.
In this description, "memory card" will be used to designate all types of card, also known as chip card, smart card or IC-card, including an electronic circuit and/or a passive element for storing digital data and possibly further enabling logical operations to be performed. All these cards will henceforth be referred to as "memory card" or simply "card".
These known systems-include memory cards which are usually cards each having at least one integrated circuit (so-called IC memory cards) forming a microprocessor comprising ROM, RAM, EPROM and/or EEPROM type memories, access to these memories being controlled by a programme stored in the integrated circuit. These known systems also include at least one administration and processing unit or station, which is external to the memory cards, and which has the capability to write and/or read in at least one zone (hereinafter called the "private" zone, or "limited access" zone) of some or all of the memory cards.
Such a station will hereinafter be called a "central administration and processing station or unit" when it has the right to modify limited-access zones on the memory cards, and a "secondary station" when it is not authorized to modify limited-access zones.
Ever since memory cards were devised, a number of applications of this technology have appeared.
A first known generation of memory cards employed a central station able to write secret information into the card, and a number of secondary stations from which it was possible to consult non-critical data stored in the card, i.e. data which did not include the possibility of revealing or eliminating secret information.
A second known generation of memory cards used principally for pay-TV systems (CPTV cards) had, for each card, a variable number of secondary stations each able to freely and exclusively deal with its own limited-access zone of the card. In pay-TV systems, the secondary stations are for example television programme emitting stations. Each secondary station is generally constituted by a specific service vendor or by a television programme emitting station.
To make the system safe, this memory card structure prevents (or renders hermetic) any communication between the different limited-access zones of the different principal administration units. Hence, any given television programme broadcasting station in principle does not have a right to access any limited-access zone of a card which is reserved for another television programme broadcasting station. For each new service vendor or each new television programme broadcasting station, it is necessary to open a new limited-access zone on the card.
To illustrate this, consider the following voluntarily-simplified situation.
Supposing a pay-TV subscriber X wishes to subscribe to three television channels A, B and C, he has to contact each of the three channels who, via the transmitted video signal, will register orders to open respective limited-access zones in the subscriber's card. In subscriber X's card, 4 limited-access zones will be opened, namely an "emitter zone" and three limited-access zones for the three channels A, B and C respectively. The limited-access zones will be opened by the central administration station which is the only station with the right to open new limited-access zones, in other words it is the only station having the overall right to manage the card's entire contents. This principle is used at present in the Eurocrypt pay-TV norm.
These known second-generation cards have the following drawbacks.
Because of the setting up of several pay-TV systems and several data distribution syst
REFERENCES:
patent: 5144663 (1992-09-01), Kudelski et al.
patent: 5319453 (1994-06-01), Copriviza et al.
Browning Clifford W.
Cain David C.
Nagra Plus S.A.
LandOfFree
Data processing system having a set of memory cards does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Data processing system having a set of memory cards, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Data processing system having a set of memory cards will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1417594