Microcomputer PC-cards

Details Microcomputer PC-cards Microcomputer PC-cards

1998-12-10

2001-01-30

Follansbee, John A. (Department: 2783)

Electrical computers and digital processing systems: processing

Processing architecture

Microprocessor or multichip or multimodule processor having...

C256S013000, C713S193000

Reexamination Certificate

active

06182205

ABSTRACT:

FIELD OF THE INVENTION
Exchangeable mass memory or PC-cards for microcomputers or personal computers (PC) have recently appeared as personal computer accessories, particularly for portable computers. In future, they could replace floppy disks and other magnetic mass storage means. They can be used as a mass memory having the same capacity as magnetic floppy disks (approximately one million bytes). Their size is no greater (credit card size with a thickness of 3 to 5 mm). They have a much faster access (several thousand times faster).
They can even be used as a random access memory for a program directly performable by the microcomputer. In this case and unlike in the case of magnetic mass memories, they do not have to be unloaded into the random access memory (RAM) of the PC to permit subsequent performance. The programs which they contain are directly performable by the PC. Mass memory or PC-cards have several memory chips and a connector (68 pin female connector according to the PCMCIA standard of the Personal Computer Memory Card International Association, 1030B East Duane Avenue, Sunnyvale, Calif.). The card can be plugged into a corresponding male connector of the computer. The connections are such that the memory can be addressed by a parallel input-output port of the PC, either as if the memory was a magnetic mass memory, or as if it was an extension of the RAM of the computer.
According to the invention, it was considered necessary to provide maximum security for the PC-cards for personal computers. Thus, their large capacity means that they can contain either significant data bases which have to be protected both during reading and writing, or expensive programs which are not to be used or duplicated without authorization. They may also be used for carrying out confidential transactions in accordance with more sophisticated programs than those existing at present, or involving larger data quantities than can be stored by secure transaction chip cards, which only have a single chip.
The presently available solutions for ensuring a certain security are indicated below.
It is firstly possible to use the sane protection types as for magnetic memories. Among these there is a possibility of concealing files by software attributes making them invisible to the user, when the latter attempts to obtain access thereto by the microcomputer. This is a standard solution for PC's operating under the DOS system. However, it is known that a well-informed user can easily get round these protections by software accessing the attributes of the files and modifying them, so that only scant protection is in fact provided.
It is also possible to use the conventional protections employed by software manufacturers in order to protect the software against copying. These solutions are of varying effectiveness and do not provide protection against use.
Finally, it is known to use security chip cards for protecting a computer or other equipment against use by unauthorized users. This solution will be described in greater detail hereinafter.
PRIOR ART
In order to ensure an access authorization to a PC, it has been proposed to add to the latter a security chip card reader, which is connected to the PC. The keyboard and screen of the computer are used as the interface for ensuring a data exchange with a view to authorization operations. The chip card has a single chip, which is a security module. The security consists of preventing PC use if the user does not supply adequate confidentiality codes. These codes are introduced from the PC keyboard, in accordance with an especially provided exchange protocol between the PC and the card. It is the PC whose use is to be protected, which is used for ensuring the exchanges. The chip card does not form part of the PC. The user takes away his security card after using the apparatus, so as not to provide free availability to an unauthorized third party. Thus, security is essentially based on the simultaneous possession of the card and a confidential code attributed to the card.
If instead of wishing to provide protection for the overall PC it is wished to provide protection to the PC card to be connected to it (because it is desired that it can be used for others for standard uses), it is then necessary for the security card connected to the card reader associated with the PC to not cause the total inhibition of operation of the PC, but selectively the inhibition of operation of the port to which is connected the PC card.
However, it is considered that this solution has disadvantages and does not provide adequate security against an undesired use of the card.
SUMMARY OF THE INVENTION
The invention proposes an original solution consisting of incorporating into the exchangeable PC card, which has several integrated memory circuits, at least one integrated security circuit able to control access to the storage areas of the mass memory.
The control takes place as a function of clearance informations which the user must supply via the computer (confidential code introduced into the keyboard or other clearance mode).
The term security circuit is here understood to mean a single integrated circuit chip having a non-volatile memory with confidential informations which cannot be transmitted to external terminals of the integrated circuit and a programmed security circuitry able to use said confidential informations and other informations supplied by the user, in order to provide validation instructions after the verification of a predetermined relationship between these two information types, the confidential data not passing to the outside of the integrated circuit.
The security circuit is preferably the same as the single circuit of an authorization or clearance chip card (that to which reference was made hereinbefore and which can be used for authorizing the operation of a computer when the user introduces it into the computer). However, in this case use is not made of an exchangeable clearance card used for authorizing the operation of the computer or connection port with the mass memory. A security chip is directly placed in the mass memory in order to secure its content.
It should be noted that the security chips used for protecting during reading or writing the data of a memory have hitherto only been used for protecting the content of the memory within the actual chip, making use of the fact that in the case of a single chip the data to be protected are not transmitted outside the chip. In addition, they were not mass memories, being instead very small memories, because in fact they were placed in the chip. In addition, the security chips used for protecting other apparatuses were incorporated into a separate security card with respect to the apparatus to be protected, said card being carried by the authorized user and not left behind in the apparatus to be protected. In this case use is not made of a chip card separate from the apparatus to be protected and transportable away from said apparatus, but instead an integrated circuit chip non-removably installed in the memory card, whose use is to be protected.
As a result of this arrangement a file protection is obtained both during reading and/or writing, which is significantly superior to that obtained by standard means (of the software type: concealed files) for the protection of personal computer files.
The security chip (referred to hereinafter also by the term security module) directly or indirectly controls the access means to the different card memory chips.
In practice, preference is given to the use of a standard security chip, i.e. of the type used in security cards for accessing apparatuses or rooms, or also in secure transaction cards. These chips use a series communication mode and in general only have six or eight connection pads with the outside, whereof there is only one data or instruction communication pad.
It is then preferable to place in the memory card a supplementary chip constituting a control processor for the card. This processor or micro controller has the function of providing an

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