DATA PROCESSING SYSTEM WHICH PROTECTS THE SECRECY OF CONFIDENTIAL DATA
BACKGROUND OF THE INVENTION 5
1. Field of the Invention
The present invention relates to a data processing system which protects the secrecy of confidential data.
2. Description of the Prior Art
Any data processing system includes a data process- 10 ing machine connected to an apparatus for transmitting data to the machine. Of these systems, some are intended to process information made up of both data of a routine nature and confidential data. In such -systems the confidential data is generally used to authorize the 15 dialogue between the machine and the operator via the said data transmitting apparatus. There are a number of specific cases which are typical of systems of this nature, and these will be described briefly herein by way of example. 20
The first case is that in which the data processing machine includes a member intended to process a predetermined confidential item of data generally referred to as a key. To prevent any illicit use the key is changed regularly. In such a system, the operator first has to 25 transmit an item of confidential data corresponding to the key, via the data transmitting device of the machine, to the member which holds the key. In this member a comparison is made between the confidential item of data received and the key, and if they are the same the 30 member authorizes a dialogue between the machine and the operator for data of any kind, be it confidential or otherwise. However, to avoid any misunderstanding in the remainder of the description, what is termed confidential data will be the data which is used as a key to 35 open the dialogue between the machine and the operator. Also, the said member which holds the key will be referred to below as the auxiliary member, in particular because of its function in the system and its interchangeable nature. 40
The second example of a known system relates to systems which employ credit cards. In cases where the credit cards contains only the personal key of the card holder, these systems are similar to those of the previous example, and the auxiliary member is formed by each of 45 the various credit cards. It is known, however, that the trend is towards introducing an integrated circuit device into cards for crediting and/or debiting. In such systems, the auxiliary member thus no longer processes simply the confidential data, but also certain of the items 50 of data passing between the machine and the operator.
In all these systems, it may be noted that the keyboard available to the operator is used to transmit both confidential data intended for the auxiliary member and also data intended for the machine after the auxiliary mem- 55 ber has authorized a dialogue. The keyboard is thus a public device at the disposal of a large number of people, but can only be used to good effect after the correct key has been transmitted. Thus, it is possible for an unauthorized user to use either the keyboard or the 60 space which separates the keyboard from the auxiliary member to discover the key which an operator will subsequently transmit to the auxiliary member.
In the case of the first example, assuming the key has been discovered, it will then be possible for the unau- 65 thorized user to gain direct access to the machine. In the case of the second example the unauthorized user will have to steal a card from an operator who meets his
requirements. With the introduction of cards incorporating integrated circuit devices, particularly in the case of credits and debits performed at a remote banking terminal or at the cash-desks of shops, theft or cards containing a key is expected to become a greater problem.
In all the systems which have just been described, the secrecy of the confidential data has so far been protected at the auxiliary member. In the systems of the first example the key is changed regularly and in the systems of the second example either a limited number of attempts is allowed for transmitting the confidential data or else the card or the integrated circuit device embodies means to prevent anybody from discovering the key. However, the unauthorized user still has the opportunity of working via keyboard or via the space which separates the keyboard from the machine.
A primary object of the present invention is to protect the secrecy of confidential data in data processing systems.
SUMMARY OF THE INVENTION
A data processing system according to the present invention is of the kind which comprises a data processing machine provided with a device for transmitting data, including confidential data, and a first member auxiliary to the machine which is intended to receive and process at least the said confidential data. The transmitting device includes a plurality of second auxiliary members which are separate from the machine, and which each include means for transmitting at least the said confidential data to the first auxiliary member by means of an information-carrying wave which is guided between the auxiliary members in a zone outside which the wave cannot be detected.
Consequently, the principle of the invention lies either in separating the functions of the transmitting devices, the infeed of the confidential code being performed by means of an auxiliary member which is given to every person who may have access to the processing system while the other functions are still performed by a public transmitting device, or else in producing the complete public transmitting device in the form of an auxiliary member which is given to every person who wishes to have access to the processing system and transmitting the confidential data in a discreet manner.
In summary, the invention provides the operator with a personal member for transmitting his confidential code, ensures that he is at all times in control of the transmission path, and allows him discreet transmission. Consequently, by combining the advantages of the invention with those of the prior art, which consisted in making the auxiliary member a member capable of preserving the secrecy of the confidential data which is contained and of confidentially processing external data with its confidential data, the invention now leaves the criminal with no means of discovering the confidential code recorded in the auxiliary member and of taking the place of the person concerned to gain access to the data processing machine.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the invention will be more clearly apparent from the following description, which is given with reference to the accompanying drawings. In the drawings: