User interface and method for the protected input of characters

1. A user interface for the protected input of characters, comprising:

an operating element having a touch-sensitive display surface, including one processor or a plurality of processors programmed:

for providing a protected input mode, wherein the protected input mode prevents display on the touch-sensitive display surface and prevents operation of a screen reader function;

for providing an invisible keyboard during the protected input mode, which defines an arrangement of invisible keys, exactly one of which is selected at each point in time,

wherein the invisible keys are allocated respectively to a character which can be input by the respective invisible key, and

for identifying a touch input which can be performed in the protected input mode as a swipe gesture in an arbitrary region on the touch-sensitive surface of the operating element,

for selecting an invisible key which is arranged alongside the previously selected invisible key on the invisible keyboard in a direction analogous to a direction of the swipe gesture.

2. The user interface as claimed in claim 1 , further wherein the processor or the processors is/are programmed:

for identifying a touch input which can be performed in the protected input mode as a tap gesture in an arbitrary region on the touch-sensitive surface of the operating element, and

for detecting the character allocated to the invisible key selected at the point in time of the tap gesture, and

for inputting the detected character,

wherein during the protected input mode, it is not possible to visually or acoustically output the currently selected invisible key and the inputted character.

3. The user interface as claimed in claim 2 ,

comprising an audio unit and/or a vibration generator, and

comprising a data processing unit programmed

to output a first acoustic and/or haptic signal during or after the swipe gesture, which signal allows no conclusion to be drawn about the direction of the swipe gesture,

to output a second acoustic and/or haptic signal during or after the tap gesture, which signal which allows no conclusion to be drawn about the detected character, and

to output a third acoustic and/or haptic signal after a touch input which was not identified.

4. The user interface as claimed in claim 3 ,

wherein the processor or one of the processors is programmed to maintain the previously selected invisible key after the identification of a swipe gesture, provided that no invisible key is arranged alongside the previously selected invisible key on the invisible keyboard in the direction analogous to the direction of the swipe gesture, and

wherein the data processing unit is programmed to acknowledge said swipe gesture by outputting the third acoustic and/or haptic signal or a fourth acoustic and/or haptic signal.

5. The user interface as claimed in claim 2 ,

wherein the processor or one of the processors is programmed to select a fixedly predefined key among the invisible keys as selected invisible key after each detection of a character.

6. The user interface as claimed in claim 5 ,

wherein the invisible keys are arranged in four lines,

wherein

the digits 1 , 2 , 3 are allocated from left to right to three invisible keys in the topmost line,

the digits 4 , 5 , 6 are allocated from left to right to three invisible keys in the second line,

the digits 7 , 8 , 9 are allocated from left to right to three invisible keys in the third line, and

the digit 0 is allocated to an invisible key situated in the bottommost line in a central position, and

wherein the processor or one of the processors is programmed to select the invisible key to which the digit 5 is allocated as selected invisible key after each detection of a character.

7. The user interface as claimed in claim 6 ,

wherein the invisible key to which the digit 0 is allocated can be selected by two successive swipe gestures downward, provided that the invisible key to which the digit 5 is allocated was selected previously.

8. The user interface as claimed in claim 1 ,

wherein the swipe gestures are horizontal and vertical swipe gestures, or horizontal, vertical and diagonal swipe gestures, and

wherein the invisible keys are arranged in a rectangular grid, such that horizontal, vertical or diagonal neighbors of the selected invisible key are uniquely determined.

9. The user interface as claimed in claim 1 ,

wherein a first processor is programmed for identifying the touch input, and

wherein a second processor is programmed for selecting the invisible key.

10. The user interface as claimed in claim 9 ,

wherein the operating element is a keypad or a touchscreen,

wherein the operating element processes touches with one or more fingertips as touch inputs and communicates them as coordinates or vectors in a coordinate system to the first processor.

11. The user interface as claimed in claim 9 , comprising a security module,

in which the first processor is arranged in a first microcontroller with a first communication interface, which connects the operating element to the first processor, and

in which the second processor is arranged in a second microcontroller with a second communication interface, which connects the first processor to the second processor.

12. The user interface as claimed in claim 11 , wherein the second processor

is configured for a switchover between a clear text mode and the protected input mode, and

is configured for an encryption of detected characters in the protected input mode.

13. The user interface as claimed in claim 12 , wherein the security module

has an external communication interface configured for communication with a data processing unit,

wherein the second processor in the protected input mode is configured for

sending a notification via the external communication interface after identification of a touch input by the first processor,

storing detected characters in an internal security memory,

encrypting detected characters using a cryptographic key,

transmitting the encrypted characters via the external communication interface, and

suppressing a transmission of coordinates or vectors of touch inputs via the external communication interface, and

wherein the second processor in the clear text mode is configured for

transmitting coordinates or vectors of touch inputs via the external communication interface.

14. The user interface as claimed in claim 13 , comprising the data processing unit, which is programmed

for switching over the second processor from the clear text mode to the protected input mode via the external communication interface,

for outputting an acoustic or haptic signal upon receiving the notification via the external communication interface, and

for suppressing a screen output while the second processor is in the protected input mode.

15. The user interface as claimed in claim 1 , wherein the processor or the processors is/are programmed to perform the following steps:

a) identifying a first touch input which can be performed in the protected input mode as a first tap gesture in an arbitrary region on the touch-sensitive surface of the operating element,

b) replacing the character allocated to the invisible key selected at the point in time of the first tap gesture by a character succeeding the character from a sequence of characters, wherein steps a) and b) are repeated until a desired character is identified;

c) identifying a second touch input which can be performed in the protected input mode as a second tap gesture in an arbitrary region on the touch-sensitive surface of the operating element, and

for detecting the character allocated to the selected invisible key at the point in time of the second tap gesture.

16. An access system, a self-service terminal, a checkout system, a payment terminal, an automatic teller machine, a transfer terminal, an automated parcel station, a smartphone, a tablet, a laptop or a personal computer which has the user interface as claimed in claim 1 .

17. A method for the protected input of characters,

wherein an operating element has a touch-sensitive display surface, the method comprising:

providing, by at least one processor, a protected input mode, wherein the protected input mode prevents display of the touch sensitive display surface and prevents operation of a screen reader function,

providing, by the at least one processor, an invisible keyboard during the protected input mode, which defines an arrangement of invisible keys, exactly one of which is selected at each point in time,

wherein the invisible keys are allocated respectively a character which can be input by the respective invisible key, and

wherein no visual or acoustic output of a position or assignment of the selected invisible key is provided during a protected input mode,

identifying, by the at least one processor, a touch input which can be performed in the protected input mode as a swipe gesture in an arbitrary region on the touch-sensitive surface) of the operating element, and

selecting by the at least one processor, an invisible key which is arranged alongside the previously selected invisible key on the invisible keyboard in a direction analogous to a direction of the swipe gesture.

18. The method as claimed in claim 17 , further comprising:

identifying, by the at least one processor, a touch input which can be performed in the protected input mode as a tap gesture in an arbitrary region on the touch-sensitive surface of the operating element,

detecting, by the at least one processor, the character allocated to the invisible key selected at the point in time of the tap gesture, and

inputting, by the at least one processor, the detected character,

wherein during the protected input mode, it is not possible to visually or acoustically output the currently selected invisible key and the inputted character.

19. The method as claimed in claim 18 , further comprising:

outputting, by a data processing unit, a first acoustic and/or haptic signal during or after the swipe gesture ( 23 ), which signal allows no conclusion to be drawn about the direction of the swipe gesture,

outputting, by a data processing unit, a second acoustic and/or haptic signal during or after the tap gesture ( 23 ), which signal allows no conclusion to be drawn about the detected character, and

outputting, by a data processing unit, a third acoustic and/or haptic signal after a touch input which was not identified.

20. The method as claimed in claim 19 , further comprising:

maintaining, by the at least one processor, the previously selected invisible key after identification of a swipe gesture,

provided that no invisible key is arranged alongside the previously selected invisible key on the invisible keyboard in the direction analogous to the direction of the swipe gesture, and

acknowledging, by the data processing unit, said swipe gesture by outputting the third acoustic and/or haptic signal or a fourth acoustic and/or haptic signal.

21. The method as claimed in claim 18 , further comprising:

selecting, by the at least one processor, a fixedly predefined key among the invisible keys as selected invisible key after each detection of a character.

22. The method as claimed in claim 21 , further comprising:

wherein the invisible keys are arranged in four lines, wherein

the digits 1 , 2 , 3 are allocated from left to right to three invisible keys in the topmost line,

the digits 4 , 5 , 6 are allocated from left to right to three invisible keys in the second line,

the digits 7 , 8 , 9 are allocated from left to right to three invisible keys in the third line, and

the digit 0 is allocated to an invisible key situated in the bottommost line in a central position, and

selecting the invisible key to which the digit 5 is allocated as selected invisible key after each detection of a character.

23. The method as claimed in claim 22 ,

wherein the invisible key to which the digit 0 is allocated can be selected by two successive swipe gestures downward, provided that the invisible key to which the digit 5 is allocated was selected previously.

24. The method as claimed in claim 17 ,

wherein the swipe gestures are horizontal and vertical swipe gestures, or horizontal, vertical and diagonal swipe gestures, and

wherein the invisible keys are arranged in a rectangular grid, such that horizontal, vertical or diagonal neighbors of the selected invisible key are uniquely determined.

25. The method as claimed in claim 17 , further comprising:

identifying, by a first processor, the touch input, and

selecting, by a second processor, the invisible key.

26. The method as claimed in claim 25 , further comprising:

wherein the operating element is a trackpad or a touchscreen,

processing, by the operating element, touches with one or more fingertips as touch inputs and communicating them as coordinates or vectors in a coordinate system to the first processor.

27. The method as claimed in claim 25 , further comprising:

switching the second processor between a clear text mode and the protected input mode, and

encrypting characters detected in the protected input mode.

28. The method as claimed in claim 27 , further comprising:

sending, by the second processor in the protected input mode, a notification via an external communication interface after identification of a touch input by the first processor,

storing, by the second processor in the protected mode, detected characters in an internal security memory,

encrypting, by the second processor in the protected mode, detected characters using a cryptographic key,

transmitting, by the second processor in the protected mode, the encrypted characters via the external communication interface, and

suppressing, by the second processor in the protected mode, a transmission of coordinates or vectors of touch inputs via the external communication interface, and

transmitting, by the second processor in the clear text mode, coordinates or vectors of touch inputs via the external communication interface.

29. The method as claimed in claim 28 , further comprising:

switching, by a data processing unit, the second processor from the clear text mode to the protected input mode via the external communication interface,

outputting, by the data processing unit, an acoustic or haptic signal upon receiving the notification via the external communication interface, and

suppressing, by the data processing unit, a screen output while the second processor is in the protected input mode.

30. The method as claimed in claim 17 , further comprising:

a) identifying, by the at least one processor, a first touch input which can be performed in the protected input mode as a first tap gesture in an arbitrary region on the touch-sensitive surface of the operating element,

b) replacing, by the at least one processor, the character allocated to the invisible key selected at the point in time of the first tap gesture by a character succeeding the character from a sequence of characters, wherein steps a) and b) are repeated until a desired character is identified,

c) identifying, by the at least one processor, a second touch input which can be performed in the protected input mode as a second tap gesture in an arbitrary region on the touch-sensitive surface of the operating element, and

d) detecting, by the at least one processor, the character allocated to the selected invisible key at the point in time of the second tap gesture.

31. A computer-readable medium,

on which is stored a computer program product, comprising a computer readable hardware storage device having computer readable program code stored therein, said program code executable by a processor of a computer system to implement a method which performs the method as claimed in claim 17 when it is processed in one processor or a plurality of processors.

32. A computer program product, comprising a computer readable hardware storage device having computer readable program code stored therein, said program code executable by a processor of a computer system to implement a method which is processed in one processor or a plurality of processors and in the process performs the method as claimed in claim 17 .