Registers – Records – Conductive
Patent
1994-03-28
1995-11-28
Shepperd, John
Registers
Records
Conductive
380 4, G06K 500
Patent
active
054710456
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to processes making it possible to lock smart or chip cards, essentially for the purpose of preventing fraudulent use thereof.
2. Description of the Prior Art
Smart or chip cards are very frequently used in applications, e.g. banking, requiring a high level of security against fraudulent use. Fraudulent use can not only take place by a thief, but also by the owner of the card. Thus, in different stages, such as the production of the chip, transportation, personalization, etc. which precede the delivery of the card to the customer, gradually the field of action of a component (the chip) is limited, because at the outset it can lave numerous possible uses. If he were able to recommence the stages in upstream form, the card holder could use the card for purposes for which this is not authorized, e.g. for making multiple withdrawals from a bank, or exceeding the limit granted.
It is known to prevent such uses by locking each of the stages by logic locks, which make it impossible to recommence the operations corresponding to these stages. These locks are generally formed by a bit (or a word) written in the non-volatile memory (EPROM or EEPROM) of the circuit of the card at the end of the stage taking place. The program corresponding to this stage tests, prior to starting up, the presence of this bit and only starts if the latter has been recognized.
This solution is not completely satisfactory, because it can occur that such locks are accidentally moved aside or erased.
In addition, during the starting up of the system on energizing the card, there is necessarily an initialization phase making it possible for criminals to neutralize the volatile memory (RAM) and override the locking system.
Finally, it is not possible to completely test the component of the card at the end of its manufacture, because this would involve activating the locks and would make it impossible to return backwards in order to supply the card manufacturer with non-personalized components. It is therefore necessary to test the component and then the card at each stage between the manufacture of the component by successively setting the locks.
SUMMARY OF THE INVENTION
In order to obviate these disadvantages, the invention proposes a process for locking a smart card incorporating a central processor, a read-only memory or ROM, an erasable programmable read-only memory or EPROM and a random access memory or RAM, in which the operation of at least one protected runnable program stored in the ROM is blocked with a logic lock entered in the EPROM, wherein there is multiple copying of the logic lock in the EPROM and a logic OR is carried out on the complete original lock and its copies in order to block the performance of the protected program on the detection of at least one copy (original included) of the lock.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in greater detail hereinafter relative to a non-limitative embodiment and with reference to the attached drawings, wherein show:
FIG. 1 the diagram of a component for a smart card.
FIG. 2 a control flow chart for a lock.
FIG. 3 a copy flow chart for a lock.
DETAILED DESCRIPTION OF THE INVENTION
The smart card component 101 shown in FIG. 1 is an integrated circuit having in the present embodiment a read-only memory or (ROM) 102, an erasable programmable read-only memory or (EPROM) 103, a central processor or (CPU) 104 and a random access memory or (RAM) 105. It can incorporate an electrically erasable programmable read-only memory or (EEPROM) 106. This device is known and the connections between these different parts are not shown. The CPU (104) is a member of the microprocessor type using a runnable program fixed at the time of the manufacture of the component in the ROM 101, as well as data entered in the EPROM 103 during the different stages, e.g. personalization, which follow the manufacture of the component and extend up to the delivery of the card to the customer. The RAM 105 enab
REFERENCES:
patent: 4734568 (1988-03-01), Watanabe
patent: 4777355 (1988-10-01), Takahira
patent: 4810862 (1989-03-01), Nakano et al.
patent: 4910393 (1990-03-01), Gercekci et al.
patent: 4988855 (1991-01-01), Iijima
patent: 5159183 (1992-10-01), Yamaguchi
Gemplus Card International
Shepperd John
LandOfFree
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