GB2388229A

GB2388229A - Keypad for generating code with scrambled displayed key sequence

Info

Publication number: GB2388229A
Application number: GB0210322A
Authority: GB
Inventors: Robert Macalonan
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-05-04
Filing date: 2002-05-04
Publication date: 2003-11-05
Also published as: GB0210322D0

Abstract

A keypad or keyboard (20, Fig. 4) is used to enter a code to enable an action to be effected, e.g. a cash withdrawal from an ATM or unlocking of a door locked by a security device. Each key contains a 7-segment type LED displaying a number, each driven by a multiplexer (22, Fig. 4) which receives signals from an EPROM (23, Fig. 4) in which random numbers are stored in the form of Data Blocks. Initially the LEDs show a conventional key layout, Fig. 6. In an ATM embodiment, after the user has entered a valid card, the key sequence displayed on the keypad is randomised, Fig. 7. After the user has successfully entered their PIN, the displayed key sequence can be returned to the conventional layout, Fig. 8, to facilitate keying for cash withdrawal. It is thus made more difficult for an unscrupulous person to observe and remember a code entered via the keypad.

Description

1,... 1- 2388229

IMPROVEMENTS IN GENERATING A CODE

The present invention relates to improvements in generating a code for permitting an action to be effected 5 particularly but not necessarily exclusively a cash withdrawal from a cash withdrawal or automatic telling machine (ATM) or device attached to for instance a bank or building society but the invention also relates for example to the unlocking of a door locked by a security 10 device. Such actions are usually implemented with a keypad comprising a plurality of keys or push-buttons displaying symbols which may be numbers, letters or other symbols or 15 combinations of same (alpha-numeric). The most usual combination is of course the numbers 0 to 9. The keys which may be of the mechanical button or touch type are depressed in a predefined sequence forming a code usually of four or more numbers e.g. a banking personal 20 identification number (PIN) to implement a specific action such as withdrawing cash or unlocking a door to permit entry. The term "Keypad" includes other types of key operated devices such as keyboards. ATMs also normally include an "ENTER" button to enable the 25 transaction, but also "CANCEL" and "CLEAR" buttons for known purposes.

For ATMs of course, before the PIN can be entered a card must be inserted into the machine and validated, the 30 card bearing the user's details such as name, bank account number etc. Once the card has been inserted and validated the PIN can be entered by pressing the appropriate numerical keys and then the "Enter" key and after the PIN has been verified the amount of cash to be

l. -2- withdrawn can be entered and withdrawn. Finally the card is returned to the customer.

It is quite easy for an unscrupulous person to 5 loiter and watch ATM customers or other persons enter their PINs by noting the position of the keys pressed on the keypad and then remembering the sequence of numbers.

This is particularly true of ATMs located in the street (so called Hole in the Wall machines). Customers may 10 then be mugged or pick-pocketed after leaving the machine so as to steal their cards and these may be used together with the unauthorized PIN to withdraw cash illegally.

This will continue until either the card holder informs his/her respective bank or building society or the 15 customer's account is emptied rendering further transactions void.

In shops and stores at present in the U.K. the purchase of goods by credit or debit cards requires a I 20 verified signature from the purchaser thus making fraudulent activity more difficult. In mainland Europe, however, such transactions are conducted solely by a PIN entered by the customer from a keypad and it is planned i to introduce this system into the U.K. soon. This will 25 inevitably lead to a greater incidence of fraud.

It is therefore an object of this invention to make t it more difficult for an unscrupulous person to observe and remember a code entered by way of a keypad or other 30 key-bearing device.

According to one aspect of the present invention, there is provided a method for generating a code for use in permitting an action to be effected, the method

-3- comprising actuating selected keys from a sequence of keys contained in a key-pad to generate and enter the code and changing the sequence of keys.

5 In one embodiment of the invention, the sequence of keys is changed after the code has been generated and entered and before a further code is generated.

Preferably each key displays a symbol so that a 10 sequence of symbols is formed by the keys and the sequence of keys is changed by changing the sequence of the symbols displayed by the keys.

Suitably each symbol is formed by light emitting 15 diodes (LEDs).

Conveniently the code is a plurality of numbers.

Preferably the symbols are alpha-numeric. I Suitably the sequence is generated by a random number generator. i 25 - Conveniently the random number generator includes an EPROM.

Preferably the action to be effected is the withdrawal of cash from an automatic telling machine 30 (ATM).

Suitably before the code can be generated a card bearing relevant information is inserted into the ATM and the information validated.

-4- Conveniently the sequence of symbols is changed upon insertion of the card into the ATM.

5 Preferably the sequence of symbols is changed after the code has been entered and validated.

Suitably the sequence of symbols always reverts to a standard format when the code has been entered and 10 validated to assist in enabling the required amount of cash to be entered, Conveniently each LED is of the 7 segment type.

IS According to another aspect of the invention apparatus is provided for generating a code for use in permitting an action to be effected, the apparatus comprising a key-pad having a key sequence in which selected keys may be actuated to generate and enter the 20 code and means is provided to change the key sequence.

In one embodiment of the invention, the means changes the key sequence after the code has been generated and before a further code is generated.

Preferably each key bears a symbol so that a sequence of symbols is formed by the keys and the means changes the sequence of symbols displayed by the keys.

30 Suitably each key is provided with light emitting diodes (LED) which forms the symbol.

Conveniently the code comprises a plurality of numbers.

l Preferably the symbols are alpha-numeric.

Suitably the means is a random number generator.

Conveniently the random number generator includes an EPROM.

Preferably the EPROM provides random signals 10 representative of particular numbers and a multiplexer is provided to supply each signal individually to each key in turn whereby to alter the number if the number represented by the signal is different to the number displayed by the key.

Suitably the action to be effected is the withdrawal of cash from an automatic telling machine (ATM).

Conveniently means are provided to permit the 20 insertion and validation of a card bearing relevant information before the code can be generated.

Preferably after validation of the card the means is enabled to change the symbol sequence.

25 - Suitably means are provided to validate the code and after validation of the code the means for changing the key sequence is enabled to change the sequence of keys on the key-pad to a standard format to assist in entering 30 the appropriate amount of cash.

Conveniently each LED is of the 7 segment type.

- - According to a further aspect of the invention, there is provided a key-pad in which each key displays a symbol and on actuation of any key a signal is generated representative of a particular symbol displayed by the 5 key and each key is also adapted to receive a signal representative of a symbol which may or may not be different from the symbol currently being displayed by the key and if the symbol is different to the symbol currently being displayed the signal being received 10 changes the symbol being displayed to that represented by the signal being received.

Preferably each symbol is displayed by a light emitting diode (LED) incorporated in the key.

In one embodiment of the invention each key has a top wall and each LED has an upper surface which is spaced from the top wall.

20 Suitably the LEDs are each adapted for connection to a random number generator.

Conveniently the LEDs are connected to a circuit board. Preferably the circuit board is connected to the random number generator.

Suitably the random number generator includes an 30 EPROM.

Conveniently a multiplexer is connected to the circuit board and the EPROM is connected to the multiplexer to supply signals representative of random

numbers thereto whereby the multiplexer can supply each signal individually to the circuit board for location at each LED.

5 An embodiment of the present invention will now be particularly described with reference to the accompanying drawings in which: Figure 1 is a transverse cross-section along lines 10 A-A of Figure 3 of a key-pad intended for an ATM; Figure 2 is an amplified view of a particular key or push-button shown in Figure 1; 15 Figure 3 is a plan view of the key-pad shown in Figure 1; Figure 4 is a block circuit diagram of the various components of the invention relating to an ATM; Figure 5 is a flow sheet relating to the processes involved in the operation of the ATM; Figures 6 to 8 show schematically possible numerical 25 keyboard displays in use; Figure 9 is a modified version of the key shown in Figure 1 and Figure 10 shows the Figure 1 version for comparison. Referring to Figures l to 3, the key-pad 1 comprises an alloy frame 2 having a number of keys or buttons 3 incorporating a conventional 7-segment light-emitting-

diode LED 4 forming an LED assembly of 10 LEDs as shown

- 8 - ( in Figure 3. In this case, each LED 4 is capable of forming one of the numbers O to 9. The keys 3 are of conventional hollow shape with side walls 5 and top walls 6. The underside of the frame 2 is machined out to 5 permit the introduction thereinto of each LED 4 into the

key or button 3 and each LED 4 is mounted on a printed circuit board (PCB) 7 (Figure 2) with a microswitch 8 connected to each LED, each microswitch 8 being mounted on the underside of the PCB 7 beneath its respective 10 LED 4.

A silicon rubber membrane 9 is attached to the base of the frame 2 to improve the spring action of the keys 3. The membrane 9 is sandwiched between the frame 2, 15 keys 3 and a stainless steel striker plate 10. Beneath the striker plate lO is mounted an electronic interface control board 11. Ten fly-lead signal cables 12, one for each LED 4 are connected at one end to the control board 11 and at the other end to the PCB 7, each cable 12 20 comprising a 10 core signal cable with 7 segment lines, a common bus and two switch lines.

The microswitch 8 has actuators 13, which are proud of the frame 2, the actuators 13 being located in 25 recesses in the striker plate 1. Each LED 4 is visible via a slot 14 in the top wall 6 of the key 3 while the circuit board 7 rests on a pad 15.

The striker plate 10 and the membrane 9 have 30 suitable apertures to permit the cables 12 to be i connected to the boards.

The frame 2 locates all the assemblies into a uniform pitch. The membrane 9 and the striker plate 10

- 9 - hold each switch 8 under compression and actuation of each switch 8 is achieved by pushing down on the top 6 of the key or button 3 causing the rubber membrane 9 to displace by a small amount e.g. 0.4 mm and the striker 5 plate 10 to be actuated. The small movement of the membrane 9 provides sufficient movement (approximately 0.2 mm) for the switch to be closed. The switch 8 (or each switch 8) when closed sends a signal to the PCB 7 representative of the symbol e.g. the number to be 10 displayed by the particular LED. The PCB 7 then supplies this as part of a code via the control board 11 to a code validation means (not shown) and an actuation device (not shown) to effect the action. These latter two items will not be described in detail as they are well known in the IS art. While not shown the key-pad 1 described may have additional keys as conventional such as "Enter", "Clear", "Delete" or "Cancel" but these and their function are not 20 shown or described as also being well known in the art.

The board 11 receives signals from a multiplex and EPROM (shown in Figure 4) serving as a random number generator. These signals find their way via the cables 25 12 and the PCB 7 to the LEDs 4 where they can alter the number currently displayed by the LED to another number if the signal represents a different number.

Referring to Figure 4 a code generator is shown 30 comprising a key-pad or keyboard 20 of the type i previously described having ten keys numbered 0 to 9.

Each key contains an LED displaying a number and each LED comprises a conventional 7-segment diode as previously shown in Figure 3 from which any of the numbers 0 to 9

-10 can be formed. The brightness of all LEDs may be varied by an ambient brightness control 21 which is connected to all LEDs and comprises a photo-transistor which varies the current through the LEDs proportionately to the level 5 of ambient light.

Each LED is driven by a two by five (10) Digit BCD (Binary Coded Decimal) Multiplex Chip (Mux)22. This greatly reduces the amount of wiring needed to connect 10 the Mux 22 to the board 11 as only 7 segment lines and 10 address lines (one line per digit)are required. The Mux 22 is wired to the board 11 and receives signals from a Erasable Programmable Read Only Memory (EPROM) 23 in which the random numbers are stored in the form of Data 15 Blocks. A typical EPROM can be selected to hold from 100 to 500, 000 number sequences but in this case only 200 number sequences (2000 numbers) are held as an example. The 20 number sequences (in blocks of ten numbers) as supplied by the EPROM 23 are passed as 40 bit BCD codes to a 40 bit BCD Sequencer/Memory block 24 for transfer to the Mux/display driver 22 in 8 bit blocks. The sequencer 24 reads each address in the EPROM 23 and transfers any data 25 stored in the address into the LED display registers 20 via Mux 22.

The particular numeric combinations are held in addresses in the EPROM. There can be hundreds of these 30 addresses and therefore hundreds of numerical combinations and sequences are available for the key-pad.

The data i.e. unique numerical combinations or sequences are each uniquely located in one of these addresses. The address 000 is unique inasmuch as it holds the standard

-11- or conventional key-pad layout for the ATM manufacturer as shown in figure 6.

The invention will from hereon in be described with 5 reference to the operation of an ATM but it will be appreciated that it would be equally applicable to other systems where the generation of a personal or security code can be seen by a third party e.g. a code operated security lock on a door.

On power up of the system Pointer 25 is set to address 000 so that the number sequence corresponding to the standard keyboard layout is generated by the EPROM 23 and supplied to the LEDs 20 by the Mux 22. The customer 15 then inserts their card into the machine and this is examined for validity. If the card is valid a "Card Valid Command" is issued, the card is "swiped" i.e. accepted and temporarily retained by the system and a signal is provided to the Pointer 25 which is incremented 20 by +1 and stored in memory to locate a new address (001) in the EPROM 23 for the next and new sequence of numeric keys which after supply to the Mux 22 are after a brief delay written to the 7 segment LEDs in a random order.

The keyboard might then look something like Figure 7 with 25 thenumbering sequence of the keys now being quite different to that of the standard keyboard in Figure 6.

The code is now entered and validated. If the code is validated the keyboard displays the standard format of 30 Figure 6 or Figure 8 to permit the key-pad to be read more easily and therefore the actual amount of cash to be entered more accurately. If the code is not validated the card is returned for another attempt after which the card would as conventional be confiscated by the machine.

-12 ( After entering the amount of cash, this is supplied to the customer and the card is returned.

On insertion of another card if the card is valid a 5 further "Card Valid Command" is issued, the card is swiped and a further increment signal is provided to the Pointer 25 which is incremented to +2 to locate a new address (002) in the EPROM 23 for the next or new sequence of numeric keys which after supply to the Mux 22 10 are written to the LEDs. The cash withdrawal process is now repeated.

A Time-out (provider set) sequence is invoked after the card has been swiped and a key has been depressed.

15 This is to reduce viewing time of the keyboard sequence and will change the keyboard layout back to the standard (Figure 6) appearance and the card will be ejected.

gate control 26 must be enabled within a pre-set period by signals from the Mux 22.

Every depression of a key is output as illuminated segments forming a key image in the form of a number.

This image is converted via a 7 segment LED to BCD converter 27 to the original BCD code. The Numeric Data 25 displayed relating to the key pressed via the MUX is gated to enable the BCD code to be transmitted to the converter 28. It is also displayed on the keyboard as an ATM BCD image 28 before conversion.

30 If an incorrect PIN code is entered then dependent on a Re-Shuffle Dip switch 29 setting one of the following actions occurs: Dip switch off the Random Number Code remains the same. The user re-enters the pin

-13 code. Dip switch on - the Random Number Code changes.

The user re-enters the pin code.

A persistent incorrect entry of the pin code causes 5 an ATM violation which is handled by the ATM provider.

The generator shown in and described with respect to Figure 4 utilises 74 series TTL logic devices and C-MOS (Complimentary Metal Oxide Semiconductor) logic devices.

Figure 5 shows the steps involved in the process of cash withdrawal using the present invention. It is believed that this is straight-forward and self explanatory which in effect repeats the processes 15 described with reference to Figure 4. However Figure 5 anticipates that a microprocessor driven version of the device would be produced operated by software in accordance with the steps of Figure 5.

20 While the key-pad shown in Figures 1 to 3 is of the mechanical pushbutton type it will be appreciated that the keys could be of the pressure sensitive touch-pad type or even of the touch-screen type.

25 While not shown before a number from one key is read on being depressed a key release signal must be detected as is conventional.

The keyboard may be fitted with a guard or shield 30 round it to narrow the angle of visibility to a bystander to prevent overlooking and thereby further inhibit fraudulent observation of the PIN.

-14 Some of the keys could be redundant i.e. not provide a signal but carry changeable symbols which cannot produce a signal.

5 While not described, the function keys "enter", "cancel", "clear" could also move around in the sequence of numbers on the key-pad. -

Furthermore the sequence of numbers could 10 automatically be changed by the pulse of a clock or oscillator instead of in response to the generation of a code. Seven segment LED displays are primarily used to 15 display Numeric Symbols in the range 0-9. Whilst they i can be used to display some Alphabetic characters e.g. A, B. C etc. they are not ideally suited to the latter simply because of confusion within the limited character -

set. For example, the numeric character '6' can be mis 20 read as the letter "b".

A typical system example developed by MACOL was purely intended for emulation of an ATM which requires Numeric input only. For other applications such as 25 security systems and encryption devices requiring a randomized complete Alpha-Numeric character set, Dot Matrix and Starburst display systems can be utilised.

The most practical device would be the Dot Matrix display. Dot Matrix displays enable characters to be formed by illumination of individual LEDs, similar to newsprint, the symbol or character is formed by a series of dots within a matrix. In newsprint, this is the number of

-15 dots per cm2. The more dots available the better the resolution or clarity of the picture. As the resolution increases so the dot diameter and pitch reduce. In our application, the dot matrix is formed by illuminating 5 individual LEDs to create the desired shape. A standard Dot Matrix display comprises 35 dots arranged in a 5 x 7 format. Higher resolution displays are available. The hardware for driving such displays would be more complex than the 7-segment type.

Referring to Figure 9 the Key 3 is similar in structure to that shown in Figures 1 and 2 except the Key 3 has a top wall 6 and the LED 4 has an upper surface 30 which is spaced from the top wall 6. In Figure 10 it 15 will be seen that by comparison the upper surface 30 of the LED 4 is hard against the underside of the key top wall (fascia) 6, By distancing the upper surface 30 of the LED 4 from the top wall 6 of the Key 4 and therefore from the slot 14 through which the LED 4 is visible, the 20 angle of vision of the LED 4 to an observer is reduced making it very difficult if not impossible for an unauthorized observer to discern the key numbers. On the other hand if the user is standing immediately above the Key 4 they will see the Key 4 as clearly as they would 25 see- the Key 4 in the Figure 10 version. This modification therefore further reduces the ability of an unauthorized bystander to discern the key-pad numbers.

Claims

CLAIMS:

1. A method for generating a code for use in permitting an action to be effected, the method comprising actuating 5 selected keys from a sequence of keys contained in a key-

pad to generate and enter the code and changing the sequence of keys before a further code is generated.

2. A method as claimed in claim l in which the sequence 10 of keys is changed after the code has been generated and entered. 3. A method as claimed in claim l or claim 2 in which each key displays a symbol so that a sequence of symbols 15 is formed by the keys and the sequence of keys is changed by changing the sequence of the symbols displayed by the keys. 4. A method as claimed in claim 3 in which each symbol 20 is formed by a light emitting diode (LED).

5. A method as claimed in any of the preceding claims in which the code is a plurality of numbers.

25 6. A method as claimed in claim 5 in which the symbols are alphanumeric.

7. A method as claimed in claim 6 in which the sequence is generated by a random number generator.

8. A method as claimed in 7 in which the random number generator includes an EPROM.

9. A method as claimed in any of the preceding claims in which the action to be effected is the withdrawal of cash from an automatic telling machine (ATM).

5 10. A method as claimed in claim 9 in which before the code can be generated a card bearing relevant information is inserted into the ATM and the information is validated. 10 11. A method as claimed in claim 10 in which the sequence of symbols is changed upon insertion of the card into the ATM.

12. A method as claimed in any of claims 3 to 10 in 15 which the sequence of symbols is changed after the code has been entered and validated.

13. A method as claimed in either of claims 10 or 11 in which the sequence of symbols always reverts to a 20 standard format when the code has been entered and validated to assist in enabling the required amount of cash to be entered.

14. A method as claimed in any of claims 4 to 13 in 2S which each LED is of the 7 segment type.

15. Apparatus for generating a code for use in permitting an action to be effected, the apparatus comprising a key-pad having a key sequence in which 30 selected keys may be actuated to generate and enter the code and means is provided to change the key sequence.

16. Apparatus as claimed in claim 15 in which the means changes the key sequence after the code has been generated and before a further code is generated.

17. Apparatus as claimed in claim 14 or claim 16 in which each key bears a symbol so that a sequence of symbols is formed by the keys and the means changes the sequence of symbols displayed by the keys.

10 18. Apparatus as claimed in claim 17 in which each key is provided with a light emitting diode (LED) which forms the symbol.

19. Apparatus as claimed in any of claims 15 to 18 in 15 which the code comprises a plurality of numbers.

20. Apparatus as claimed in claim 19 in which the symbols are alphanumeric.

20 21. Apparatus as claimed in any of claims 17 to 20 in which the means is a random number generator.

22. Apparatus as claimed in claim 21 in which the random number generator includes an EPROM.

23. Apparatus as claimed in claim 22 in which the EPROM provides random signals representative of particular numbers and a multiplexer is provided to supply each signal individually to each key in turn whereby to alter 30 the number if the number represented by the signal is different to the number displayed by the key.

24. Apparatus as claimed in any of claims 17 to 23 in which the action to be effected is the withdrawal of cash from an automatic telling machine (ATM).

5 25. Apparatus as claimed in any of claims 17 to 24 in which means are provided to permit the insertion and validation of a card bearing relevant information before the code can be generated.

10 26. Apparatus as claimed in claim 25 in which after validation of the card the means is enabled to change the symbol sequence.

27. Apparatus as claimed in claim 26 in which means are 15 provided to validate the code and after validation of the code the means is enabled to change the sequence to a standard format to assist in entering the appropriate amount of cash.

20 28. Apparatus as claimed in any of claims 23 to 27 in which each LED is of the 7 segment type.

29. A key-pad in which each key displays a symbol and on actuation of any key a signal is generated representative 25 of a particular symbol displayed by the key and each key is also adapted to receive a signal representative of a symbol which may or may not be different from the symbol currently being displayed by the key and if the symbol is different to the symbol currently being displayed the 30 signal being received changes the symbol being displayed to that represented by the signal being received.

30. A key-pad as claimed in claim 29 in which each symbol is displayed by a light emitting diode (LED) incorporated in each key.

5 31. A key-pad as claimed in claim 30 in which each key has a top wall and each LED has an upper surface which is spaced from the top wall.

32. A key-pad as claimed in claim 31 in which the LEDs 10 are each adapted for connection to a random number generator. 33. A key-pad as claimed in claim 32 in which the LEDs are connected to a circuit board.

34. A key-pad as claimed in claim 33 in which the board is connected to the random number generator.

35. A key-pad as claimed in any of claims 32 to 34 in 20 which the random number generator is an EPROM.

36. A key-pad as claimed in claim 35 in which a multiplexer is connected to the circuit board and the EPROM is connected to the multiplexer to supply signals 25 representative of random numbers thereto whereby the multiplexer can supply each signal individually.

37. A method for generating a code substantially as hereinbefore described with reference to the drawings.

38. Apparatus for generating a code substantially as hereinbefore described with reference to the drawings.

39. A keypad substantially as hereinbefore described with reference to the drawings.

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