GB2154350A - Preventing misuse of information stored on computer tapes and the like - Google Patents

Abstract

Misuse of information stored on computer tapes and the like is prevented by providing a metal detector guarding the door to the computer room where the tapes are stored and used, and providing an annular foil (6) of aluminium or aluminium alloy irremovably secured on or in the spool (4B) or on the housing of the computer tape so that the detector sounds an alarm and closes the door if someone tries to remove a tape (3) from the room. <IMAGE>

Description

SPECIFICATION Preventing misuse of information on computer tapes and the like This invention relates to a system for preventing fraudulent copying and stealing of information stored on computer tapes and the like.

Fraudulent or unauthorised copying or stealing of information on computer tapes is presently a great source of anxiety to companies and other authorities, particularly where sensitive information is stored on computer tapes.

Like audio tapes and video tapes it has not so far been possible to devise a secure system to overcome this problem.

The conventional way to minimise the problem is to keep the tapes locked up and to provide access to the computer room by a conventional security system such as a card access system or other access control system where only certain people are allowed to use the tapes and the computer room. This of course is optn to abuse as it relies heavily on individual integrity.

Another proposal is to encrypt the information stored on the tape so that only equipment provided with a descrambling arrangement will be able to satisfactorily utilise the computer tape. However, like all encryption systems it is usually possible to obtain or gain access to descrambling equipment or to break the code and thus overcome the system for fraudulent or unauthorised use.

It is an object of the present invention to provide a relatively secure system for preventing unauthorised copying or stealing of information stored on computer tapes and the like, which is relatively cheap and simple to instal and which provides the minimum of inconvenience to the authorised user.

According to the present invention there is provided a system for preventing unauthorised copying or stealing information stored on computer tapes or the like, wherein a computer room in which information is stored and normally used has its exit guarded with an archway metal detector such as an induction balanced or pulsed field detector, and the storage device such as a tape has its carrying spool or housing provided with a lightweight metallic layer tag for practical purposes irremovably secured on or in the spool or housing, the system being such that an attempt to remove the storage device from the computer room will cause the detector gate to raise an alarm.

According to another aspect of the present invention there is provided a spool for a computer tape for use in the system described in the above paragraph, comprising a hub around which the tape is to be wound, and a tape support flange secured to the hub, the flange carrying an annular metallic layer tag which for practical purposes is irremovably secured to the flange.

Preferably the tag is a metal foil tag and the same size as the flange of the tape spool and is irremovably secured either by a self-adhesive-backed foil or alternatively, and prefera bly, the metal tag is integrally moulded into the spool when the spool is manufactured.

We have found that the magnetic field produced by our pulsed field archway metal detector gives a satisfactory detection with no chance of the field deleteriously affecting the information contained on the magnetic tape.

In order that the invention can be clearly understood reference will now be made to the accompanying drawings in which:~ Figure 1 shows schematically an archway metal detector operating on the pulsed field principle, Figure 2 shows a computer tape on its spool, Figure 3 shows a metal foil tag as is secured to the tape spool of Fig. 2, and Figure 4 shows a block circuit diagram of the detector of Fig. 1.

Referring to Fig. 1 of the drawings an archway metal detector such as the one manufactured by Adams Electronics, Model No.

AMD575 comprises a transmitter panel 1, a receiver panel 2 and associated electronic ELEC. The transmitter panel 1 sets up a pulsed magnetic field which is sensed by the receiver panel 2 and any moving metal object passing between the panels is immediately detected because it causes a distortion of the magnetic field configuration in the form of decay.

A computer tape spool is shown in Fig. 2 and comprises the computer tape 3 wound between flanges 4A and 4B around a hollow hub 5. Typical dimensions of the backing flange would be approximately 10 inches outside diameter and the hub would have a diameter of between 4 and 5 inches.

The flange 4B of the spool has an annular recess 4C and in this recess is irremovably fixed a metal detection tag in the form of a disc-like aluminium foil 6 as shown in Fig. 3.

This can be a self-adhesive foil which is glued to an existing tape spool or alternatively and preferably the foil is moulded into the spool flange during manufacture of the spool. Typical metal thickness would range from 100 to 300 microns. Alternatively a screen printing technique can be used to apply a metal coating. It is also envisaged that a metallic powder or flake could be incorporated into the plastics moulded spool to provide the same effect as the foil.

It should be noted that computer tape transport mechanisms are sensitive to inertial loads which occur when the tape stops and starts. They are designed to work with plastics mounted spools of predetermined design and it is therefore important not to significantly change the weight of the spool by the addi tion of the metal foil. The metal foil or its equivalent is preferably of aluminium or an alloy of aluminium berillium and copper. In an adhesive backed foil the aluminium or aluminium alloy can be plastics-coated for additional strength. The foil should not be thicker than about 500 microns otherwise inertial problems could arise.

Preferably if the foil is stuck with adhesive onto the spool, it is scribed into segments to make it more difficult for someone to peal off the foil.

The invention is also applicable to other information storage media such as floppy discs. If the floppy disc already has a metallic ring such as a magnetic ring, then it may not need a foil tag to be used in the system of the present invention since the metal detector could have the sensitivity adjusted to detect the magnetic ring. Otherwise an annular foil can be applied to the floppy disc packet or envelope or even incorporated within the floppy disc itself during manufacture.

In operation of the system the archway metal detector is located at the exit to the computer room in which the computer tapes are stored and used. The archway metal detector may in fact guard a common exit/entrance.

Reffering now to Fig. 4 there is shown a block schematic diagram of the electonic ELEC of the metal detector of Fig. 1. In the drawing a transmitter TX provides a low power square wave signal to the transmitter coil TC housed in the panel 1 of Fig. 1 at a relatively low frequency, e.g. 200 Hz. The receiver coil RC housed in the panel 2 of Fig. 1 detects the electromagnetic pulsed field and provides a pulsed signal to the receiver RX. This signal is fed into a detector DET which amplifies the signal and removes unwanted interference by common mode rejection.

The signal then passes through a gate G which is under the control of a sampling circuit SAMPLE. The sampling circuit SAM PLE opens the gate for a period just after the pulse has finished e.g. 50 microseconds later under the control of the transmitter TX via line C. The gate is opened for a short period (much less than the space between pulses) e.g. 100 microseconds.

If metal is in the archway during that sampling period then a decaying signal will be detected by the receiver coil RC and an integrator INT integrates a succession of the decay signals to provide a sawtooth integration pulse. A number of these integration pulses are fed into a d.c. amplifier AMP which converts the integration pulses into a changinglevel d.c. signal.

The changing-level d.c. signal is representative of the amount of metal in the archway, and the signal is fed to a trigger circuit TRIG, whose sensitivity can be adjusted to respond to a high metallic quantity (low sensitivity) or a low metallic quantity (high sensitivity) to operate an alarm circuit ALARM which can be visible, audible and operates a relay RLY to close the doors RS of the computer room via dotted line by actuating e.g. an electromagnetic pneumatic or hydraulic device controlling the doors via a connection C represented by the broken line.

The transmitted pulses from the transmitter coil TC are low power e.g. 12 volts, 400 microseconds, and do not affect the tape.

It is found that by providing an aluminium alloy tag of significant size, that is to say the one shown in Fig. 3 has an outside diameter of about 10 inches and an inside diameter of about 5 inches with a thickness in the range stated, provides a significant distortion of the magnetic field so that easy detection is possible even though the magnetic level is relatively low. At this low level the field is not strong enough to cause any degradation of the information contained on the magnetic tape.

If an attempt is made to remove a computer tape from the room through the archway detector, then the detector will provide an alarm signal to a security guard, and as well as providing an alarm, the archway metal detector automatically prevents the door DRS opening, thus preventing exit from the computer room until security personnel arrive.

Claims (7)

1. A system preventing unauthorised copying or stealing information stored on computer tapes or the like, wherein a computer room in which information is stored and normally used has its exit guarded with an archway metal detector such as an induction balanced or pulsed field detector, and the storage device such as a tape has its carrying spool or housing provided with a lightweight metallic layer tag for practical purposes irremovably secured on or in the spool or housing, the system being such that an attempt to remove the storage device from the computer room will cause the detector gate to raise an alarm.

2. A system as claimed in claim 1, wherein the storage device is a tape and the tag is in the form of a self-adhesive annular metal foil stuck to the surface of the spool on which the tape is carried.

3. A system as claimed in claim 1, wherein the storage device is a tape and the tag is in the form of a metal foil secured to the spool during moulding the spool.

4. A system as claimed in any preceding claim, wherein the metallic layer is a foil of aluminium or aluminium alloy of generally annular configuration and having a thickness in the range 100 to 300 microns.

5. A system substantially as hereinbefore described with reference to the accompanying drawings.

6. A spool for a computer tape for use in the system according to any preceding claim, comprising a hub around which the tape is to be wound, and a tape support flange secured to the hub, the flange carrying an annular metallic layer tag which for practical purposes is irremovably secured to the flange.

7. A spool for a computer tape substantially as hereinbefore described with reference to and as illustrated in Figs. 2 and 3 of the accompanying drawings.