GB2196169A - An encoding/decoding device - Google Patents

Abstract

An encoding/decoding device comprises a base member in the form of a rectangular sheet (1) presenting a code surface (2) on which is marked a scale (3) in the form of a 12 hour clock face scale. The scale (3) borders and encloses a region (11) provided with visually distinct areas defining an information lattice and identified by respective indicia (6). A viewing member has numbered sighting windows 1-10 and is attached to the base member so as to be rotatable over the code surface to bring a pointer (10) on the viewing member into registry with a selected point on the scale in order to identify a corresponding visually distinct area then visible through the or a selected sighting window. Two superposed viewing members may be independently movable over the code surface, each viewing member having a respective pointer. The device may be used for computer software protection. <IMAGE>

Description

SPECIFICATION An encoding/decoding device THIS INVENTION relates to the encoding and decoding of information and, in particular, to an encoding/decoding device which finds particular application in the protection of computer software against illegal copying.

The illegal copying of computer programs, especially programs recorded on magnetic tape in cassettes for use with home computers, has a considerable impact on the sales of the legitimate product, thereby acting as a disincentive to the development and marketing of such programs. The fact of illegal copying also has to be taken into account in the pricing of the legitimate program, so that such copying also acts to maintain the cost of such programs of an unnecessarily high level.

It is an object of the present invention to provide an encoding/decoding device which finds particular application in the protection of computer programs by at least hindering the use of copied computer programs.

According to the invention, in a first aspect thereof, there is provided an encoding/decoding device comprising a base member presenting a code surface having a scale bordering a surface region provided with visually distinct areas, and a viewing member having at least one sighting window formed therein and movable over the code surface to bring a pointer on the viewing member into registry with a selected point on the scale in order to identify a corresponding visually distinct area then visible through the or a selected viewing window.

The present invention also provides a software system comprising an encoding/decoding device in accordance with the first aspect of the invention in combination with a recording medium carrying software for use with a computer, the software comprising an access section for preventing the use of a main section of the software until information determined from the encoding/decoding device in accordance with instructions given by the access section of the software is input to the computer.

In order that the invention may be readily understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a first encoding/decoding device embodying the invention; Figure 2 is a cross-section on the line ll-ll of Fig. 1; Figure 3 is a plan view of a base member of the device of Figs. 1 and 2; Figure 4 is a plan view of a viewing member of the device of Figs. 1 and 2; and Figure 5 is an exploded perspective view of a second encoding/decoding device embodying the present invention.

Referring to Figs. 1 to 4, an encoding/decoding device embodying the present invention comprises a base member in the form of a rectangular sheet 1 made, for example, of cardboard or plastics material. The upper surface of the base member 1 constitutes a code surface 2 on which is marked a scale 3 in the form of a 12 hour clock face scale having hour graduations 4 and minute graduations 5.

The scale 3 borders and encloses a region 11 of the code surface which is provided with visually distinct areas, each area being visually diferentiated by means of a distinct indicia 6, for example, a letter, numeral or other symbol.

The visually distinct areas are arranged so that the spatial relationships therebetween define an information lattice.

A viewing member 7 overlies the base member 1 and is attached to the base member 1 by a pivot member 12 such as an eyelet or other fastener, so as to be rotatable over the code surface 2 with the axis of rotation centred on the scale 3. The viewing member 7 comprises an oval transparent lamina 17 to which is fixed a part-oval opaque mask 8 formed with non-uniformly distributed circular apertures which define sighting windows 9 in the composite viewing member 7.

The mask has an elongate pointer portion 10 extending along the long axis of the transparent oval lamina 7. The sighting windows 9 of the viewing member are numbered, in the present case from 1 to 10. However, as few or as many sighting windows as desired may be provided, depending upon the circumstances.

In order to decode or encode message using the device of Figs. 1 to 4, the viewing member 7 is rotated to bring the pointer 10 into registry with a selected graduation of the scale 3 and a resulting encoding symbol 6 is read from the region 11 of the code surface within the scale through a selected one of the sighting windows.

Fig. 5 illustrates another encoding/decoding device embodying the present invention, which device comprises a base member 21, a first or lower viewing member 22 and a second or upper viewing member 23 superimposed on the first viewing member 22. The upper and lower viewing members 22 and 23 are attached to the base member 21 in the assembled condition of the device by a suitable fastener permitting independent rotation of the members 22 and 23 relative to the member 21 about a common axis 36 of rotation.

The base member 21 has substantially the same form as the base member 1 of the device shown in Figs. 1 to 3 and consists of a substantially rectangular sheet of cardboard or plastics material having its upper surface formed as a code surface provided with a 12 hour clock scale 24 with hour graduations 25 and minute graduations 26. The scale 24 encloses a region 34 of the code surface which is divided into visually distinct areas differenti ated by means of indicia 27.

The lower viewing member comprises a substantially rectangular sheet of transparent material provided with an opaque mask 28 which defines a sighting window 29 in the form of a transparent spiral strip in the- lower viewing member 22. Also provided on the member 22 is a pointer 30 extending along the long axis of the member 22.

The upper viewing member 23 has a similar form to the lower viewing member 22 but has smaller dimensions. The transparent member 23 carries an opaque mask 31 which defines a plurality of strip like sighting windows 35 extending radially from the common axis 36 of rotation of the two viewing members. The sighting windows 35 are identified by respective letters of the alphabet, there being five windows in the present case identified by the letters A to E. Of course, as few or as many windows 35 as desired may be provided depending upon the circumstances. The viewing member 23 is also provided with a pointer 33 extending along the longer axis of the member 23.

The opaque masks 28 and 31 may be provided on the members 22 and 23 by any suitable process, such as printing.

In order to decode or encode a message using the encoder of Fig. 5, the lower viewing member 22 is first rotated to bring the pointer 30 into registry with a selected hour graduation 25 on the clock scale 24. Thereafter, with the viewing member 22 retained in position, the upper viewing member 23 is rotated relative to the member 22 so as to bring the pointer 33 into registry with a selected minute graduation of the clock scale 24. A resulting encoded symbol 27 is then read from the code surface 34 of the base member 21 through the intersection of a selected radial sighting window 35 with the spiral sighting window 29, which intersection uniquely defines one of the visually distinct regions of the code surface.

It will be appreciated from the above description that an encoding/decoding device embodying the present invention can be used in any-situation where a coded message is to be generated or decoded. However, an encoding/decoding device embodying the present invention finds particular aplication in deterring and hindering the copying of computer programs and the like.

In use of the encoding/decoding device to hinder the use of an unauthorised copy of a computer program, a program for sale to a consumer, for example for use with a home computer, will be sold together with an encoding/decoding device embodying the present invention. The computer program, normally recorded on an audio cassette tape as the recording medium, is provided with an introductory or access routine which either prevents access to the main program on the tape by preventing loading of the main program or prevents running of the main program until a particular code has been indicated to the computer by the user.Thus, when the access routine of the program is run, it will determine whether the user possesses the particular encoding/decoding device associated with that program by asking the user to carry out one or more operations using the encoding/decoding device and requiring the user to input the decoded result of.the operation or operations.

For example, in the case of an encoding/decoding device as shown in Figs. 1 to 4, the access routine of the program may instruct the user to bring the pointer 10 of the viewing body into registry with a particular graduation of the scale 3 and then ask the user to input the symbol visible through a selected one of the sighting windows 1 to 10. If the coded result supplied to the computer in response to its request coincides with that expected by the computer, it may be assumed that the user is in possession of the corresponding encoding/decoding device and the main program may then confidently be released for use. The security of the program can, of course, be increased by using an access program routine which requires the user to carry out a number of operations using the encoding/decoding device.The access routine includes a randomising function so that the instructions given to the user and the corresponding result are likely to be different each time the user requests access.

An encoding/decoding device embodying the present invention may be made of a size (for example 10 cmx 6 cm) such it can conveniently be accommodated in the casing of a magnetic tape cassette and preferably is provided with means for attaching it to the tape holder itself, so that the encoding/decoding device is stored together with the tape itself (as is usual) at a location remote from the displayed empty cases. For example the fastener holding the base and viewing members together may be provided with a head dimensioned to snap into an existing aperture of the tape spool.

An encoding/decoding device embodying the present invention may be readily massproduced from cheap lightweight materials and thus provides a low cost, convenient means of protecting a computer program against copying which is independent of the specific type or make of computer with which the protected program is to be used.

Claims (18)

1. An endocing/decoding device comprising a base member presenting a code surface having a scale bordering a surface region provided with visually distinct areas and a viewing member having at least one sighting window formed therein and movabie over the code surface to bring a painter on the viewing member into registry with a selected point on the scale in order to identify a corresponding visually distinct area than visible through the or a selected viewing window.

2. A device according to Claim 1, wherein the scale encloses the region of the code surface provided with visually distinct areas and the viewing member is rotatable relative to the base member to move the pointer along the scale.

3. A device according to Claim 2, wherein the scale is a clock face scale.

4. A device according to Claim 2 or 3, wherein the base member is a lamina body having one face thereof as the code surface.

5. A device according to claim 4, wherein the base member is substantially rectangular in shape.

6. A device according to Claim 4 or 5, wherein the viewing member is a lamina body fastened to the base member to overly the code surface thereof.

7. A device according to Claim 6, wherein the viewing member has an opaque portion formed with the sighting window or windows.

8. A device according to Claim 6, wherein the viewing member comprises a transparent lamina body to which an opaque layer of ma- terial is applied to form the opaque region.

9. A device according to any one of Claims 6 to 8, wherein the viewing member has an oval shape.

10. A device according to any one of Claims 1 to 8, comprising first and second superimposed viewing members independently movable over the code surface of the base member to bring respective pointers into registry with respective selected points on the scale in order to identify a corresponding visually distinct area than visible through superimposed viewing windows of the first and second viewing members.

11. A device according to Claim 9, wherein the first and second viewing members are rotatable relative to the base member about a common axis.

12. A device according to Claim 11, wherein the first viewing member has a sighting window in the form of a spiral strip.

13. A device according to Claim 12, wherein the second viewing member has at least one sighting window in the form of a strip extending radially with respect to the common axis of rotation of the viewing members.

14. A device according to any one of Claims 10 to 13, wherein each of the base member, the first viewing member and the second viewing member is a substantially rectangular lamina body.

15. An encoding/decoding device substantially as hereinbefore desribed with reference to Figs. 1 to 4 of the accompanying drawings.

16. An encoding/decoding device substantially as hereinbefore described with reference to Fig. 5 of the accompanying drawings.

17. A software system comprising an encoding/decoding device according to any preceding claim in combination with a recording medium carrying software for use with a computer, the software comprising an access section for preventing the use of a main section of the software until information determined from the encoding/decoding device in accordance with instructions given by the access section of the software is input to the computer.

18. Any novel feature or combination of features described herein.