Method of entering a code on a touch surface

Abstract

Method for entering a code comprising a first number of characters on a touch-sensitive surface (12). The method comprises the following steps: a) detecting contact made by a user on the touch-sensitive surface (12), b) emitting by the touch-sensitive surface (12) a series of at least one counting vibration (26, 28, 30, 32) which can go up to a second number of vibrations, c) detecting the stopping of the contact after a third number of vibrations included between 1 and the second number, d) recording the third number of vibrations which corresponds to a character of the code, e) repeating step a) up to step d), until recording a number of characters equal to the first number. In the method, when the series of at least one counting vibration comprises at least two vibrations (26, 28, 30, 32), two consecutive vibrations are separated by a time interval whose duration is random. Figure for the abstract: figure 3

Description

Title of the invention: Method for entering a code on a touch-sensitive surface

[0001] The invention relates to a method for entering a code on a touch-sensitive surface. More specifically, the invention relates to the secure entry of a confidential identification code on a touch-sensitive surface of an electronic payment terminal by a user with a visual impairment, for example a visually impaired or blind user. The invention also relates to a payment method comprising the steps of the entry method, as well as to an electronic payment terminal for implementing the entry method.

[0002] It is difficult for a visually impaired person to enter their PIN confidentially on an electronic payment terminal. Indeed, the use of a virtual keyboard on a touch surface requires that the screen keys be detected visually. The use of voice commands is not an option because a malicious person could intercept the code. There are boxes that can be added to the terminal in order to communicate in Braille with the payment terminal, but these systems are complex to implement because they require the installation of an additional part on the terminal.

[0003] Already known in the prior art, from document US 10489567, is a method for entering a personal identification number (PIN, also called a PIN code) which does not require the installation of an additional part for use by a visually impaired user. To do this, the user communicates with the touch surface by exerting different levels of pressure on the touch surface, for a specific period of time. Each character of the code corresponds to a pressure exerted at a certain level, for a certain time. The change in pressure indicates to the terminal that a character of the code has been entered and that the entry of another character of the code begins. The user indicates that the entry of the code is complete by ceasing to exert pressure.This allows the user to enter the code without having to move their finger or stylus away from the surface, which prevents an attacker from entering the code, for example by simply timing the time during which pressure is applied to enter a character. However, such a method is complex to implement because the user must concentrate on the time passing and the level of pressure applied.

[0004] The invention aims in particular to provide a method that is easier to implement artwork.

[0005] To this end, the invention relates to a method for entering on a touch-sensitive surface a code comprising a first number of characters, preferably four characters, comprising the following steps: a) detection of contact made by a user on the touch-sensitive surface, b) emission by the touch-sensitive surface of a series of at least one counting vibration which can go up to a second number of counting vibrations, c) detection of contact stopping after a third number of counting vibrations included between 1 and the second number, d) recording the third number of counting vibrations which corresponds to a character of the code, e) repeating step a) up to step d), until a number of characters equal to the first number is recorded, method in which, when the series of at least one counting vibration comprises at least two counting vibrations, two consecutive counting vibrations are separated by a time interval whose duration is random.

[0006] Haptic feedback is thus used to guide the user through the counting required to enter the code. This simplifies code entry by a visually impaired user, or any other user. The user is only required to maintain pressure while counting the vibrations until the number of vibrations corresponds to the character to be entered, and then release the pressure. This improves the input result, i.e., it encourages correct code entry.

[0007] Furthermore, the method requires a fairly simple device for implementing the method, which must not discriminate between different pressure levels.

[0008] Due to the random duration interval, the time required to enter a character is unknown and a malicious person cannot identify a character by simply timing the pressure time. This increases the security of the process.

[0009] The characters of the code can be numbers or letters, or even special characters such as symbols.

[0010] According to other optional characteristics of the method, taken alone or in combination:

[0011] - The touch surface is a touch surface of an electronic payment terminal. The code can be a confidential identification code.

[0012] - The method further comprises after step a) and before step b) a step during which a first vibration of constant amplitude is emitted, called the first calibration vibration, followed by a second vibration of decreasing amplitude, called the second calibration vibration. Thus, before entering characters, the user is allowed to familiarize themselves with the vibrations emitted by the touch surface, and is informed that the entry is about to begin. This step allows for "sensory calibration", according to, for example, the work of the Acoustic Vibrations laboratory of FINS A in Lyon. This encourages the entry of a correct code. Advantageously, each of these calibration vibrations lasts approximately one second. Typically, the first calibration vibration has a frequency of 200 Hz with an amplitude of 100%, the second calibration vibration has a decreasing amplitude from 100% to 0%. The vibrations are typically emitted by a haptic actuator, for example, a linear resonant actuator (LRA). For such an LRA, the 100% amplitude is, for example, 1.2 g, i.e., 11.76798 m / s2. For an LRA, the amplitude can range from 0.8 to 5 g depending on its size. Piezoelectric oscillators have acceleration amplitudes of up to several g, depending on their size.

[0013] - During step b), the counting vibrations are separated by an interval of random time, between 0.1 and 2 seconds, preferably between 0.2 and 1 second. In step b), the counting vibrations are separated by a time interval of 0.1 to 3 seconds, preferably 0.2 to 1.5 seconds. Thus, the time dedicated to entering the code is not too long but the intervals are long enough for the user to release pressure at the right time. This reduces the risk of input errors. User comfort is good while input efficiency is correct. In addition, the random duration parameter allows for gaining entropy on the code, and thus reducing the chances for a potential hacker to guess the code.

[0014] - During step b), the counting vibrations are emitted at a frequency ranging from 100 to 300Hz, preferably 200 Hz.

[0015] - During step b), each counting vibration is emitted for a duration between 0.1 and 2 seconds, preferably between 0.2 and 1 second.

[0016] Thus, this makes it possible to participate in increasing the entropy of the code so as to improve the security of the process by reducing the possibilities for a potential hacker to guess the code.

[0017] - During step b), the amplitude of the counting vibration increases to a maximum, then decreases. In one example, the amplitude increases linearly to the maximum, then decreases linearly.

[0018] - At the end of step c) and before step e), the touch surface emits at least one vibration. Preferably, the touch surface emits a random number of vibrations after contact has ceased. These decoy vibrations are not perceived by the user, only the terminal knows when the user has removed their finger. Thus, the use of an accelerometer, stuck on the terminal, would not allow a malicious person to guess the entered code. This increases the entropy of the code.

[0019] The invention also relates to a payment method comprising the steps of the method of entering a confidential code as described above, further comprising at least one of the following steps: - prior to step a), vocal statement of the transaction amount, - after step e), transmission of a voice message informing about the outcome of the entry.

[0020] The invention also relates to an electronic payment terminal comprising a touch-sensitive surface configured to implement the method of entering a code as described above, the touch-sensitive surface being equipped with a haptic actuator configured to execute step b) of the method. The haptic actuator is for example a piezoelectric actuator, a linear resonant actuator (LRA), which uses a magnetic mass suspended by springs, or a vibrating motor with an eccentric rotating mass. The piezoelectric actuator has the advantage of being compact and having a wide frequency range (remains effective between 50 and 1000HZ). Optionally, the haptic actuator is also configured to emit first and second calibration vibrations. Brief description of the figures

[0021] The invention will be better understood on reading the following description given solely by way of example and with reference to the appended drawings in which:

[0022] [Fig-1] illustrates different stages of a method of entering a code according to a mode of realization of the invention;

[0023] [Fig.2] illustrates the evolution over time of vibrations emitted during a step illustrated in [Fig.l];

[0024] [Fig.3] illustrates other steps of the method shown in [Fig.l];

[0025] [Fig.4] illustrates the evolution over time of vibrations emitted during illustrated stages on [Fig.3]. Detailed description

[0026] Figures 1 and 3 show different steps of a method for entering a code according to the method of the invention, during which an electronic payment terminal 10 is manipulated by a user. Prior to these steps, a transaction amount has been entered by a merchant. If necessary, the merchant has carried out the steps required for the entry to be made using the method according to the invention. More specifically, the merchant has launched an application allowing the implementation of the method. For use by a visually impaired person, the amount of The transaction can be spoken. When entering the code, the user can be guided vocally. The code to be entered includes an initial number of characters. For example, the code includes 4 digits, and these digits are whole numbers ranging from 0 to 9. The entry of the PIN code by the blind person must be done ergonomically (minimizing, for example, user errors), but also secure (a potential hacker must have great difficulty extracting the entered code).

[0027] The terminal 10 comprises a chip card reader and a magnetic card reader, not shown. It also comprises a touch-sensitive surface 12, making it possible in particular to view information such as transaction amounts, and to enter these same amounts as well as confidential customer identification codes. The terminal 10 also comprises electronic components gathered in one or more secure enclosures, not shown. All these components are included in a housing 14. The touch-sensitive surface 12 of the electronic payment terminal 10 according to the invention comprises a haptic actuator, not visible in the figures. The haptic actuator is configured to allow the touch-sensitive surface 12 to emit vibrations emitted during steps of the input method.

[0028] In Figures 1 and 3, the terminal 10 is shown in the hands 16 of a user. More precisely, during the various steps, the housing 14 of the terminal 10 rests in the hands 16 of the user.

[0029] [Fig.l] illustrates three steps of the input process, during which a sensory calibration is carried out. These steps take place prior to the entry of the code.

[0030] First of all, the user takes the terminal 10 in hand, step P, that is to say the casing 14 of the terminal 10 rests in his hands, and the hands 16 are in contact with the casing 14. During this step P, the hands 16 are not in contact with the touch surface 12.

[0031] The user is asked to establish contact with the touch-sensitive surface 12. The contact is established via a finger 18 of the user, step CC. It could be established via a stylus. The user can establish this contact anywhere on the touch-sensitive surface 12. The finger 18 therefore comes into contact with the touch-sensitive surface 12, step CC, which is symbolized by the reference 20. The contact 20 is maintained during the step following step CC.

[0032] Following step CC, step a) of the method according to the invention is carried out, during which the contact exerted by the user on the touch-sensitive surface 12 is detected.

[0033] As soon as the contact 20 is detected, a first calibration vibration 22 is emitted, followed by a second calibration vibration 24, during the step VC.

[0034] [Fig.2] illustrates the evolution over time, expressed in seconds, of the amplitude of the vibrations 22 and 24, expressed in m / s2. As illustrated in [Fig.2], the first calibration vibration 22 is continuous, that is to say that its amplitude is constant. The amplitude of the second calibration vibration 24 is decreasing, from 100%, down to 0%. Each of these vibrations 22, 24 lasts approximately one second. In [Fig.2], the first vibration 22 has a frequency of 200 Hz and an amplitude of 100%, the second vibration 24 has a decreasing amplitude from 100%. Thus, before entering the characters, the user is allowed to familiarize himself with the vibrations emitted by the touch surface, and he is informed that the entry is about to begin.

[0035] After a random duration, between 0.5 and 5 seconds (preferably 2 seconds), the code entry can begin. This random duration makes it possible to increase the entropy of the code.

[0036] [Fig. 3] illustrates the entry of the numeric character “4” using the entry method according to the invention. [Fig. 3] represents a case in which the number “4” is not the first character of the code. It follows another character that has already been entered. Also, the contact 20 has been stopped, step P. If, in another case not described, the number “4” was the first character of the code, its entry would be carried out directly after the sensory calibration step described in FIGS. 1 and 2, and the finger 18 would already be in contact 20 with the touch-sensitive surface 12, step C1 of contact between the user’s finger 18 and the touch-sensitive surface 12. In this other case, the contact 20 would have been maintained since the calibration, for 1 second as specified above.

[0037] During step C1, the contact 20 is established in the same way as in step C1. Step a) of the method according to the invention is then carried out, during which the contact 20 exerted by the user on the touch surface 12 is detected.

[0038] Following detection of the contact 20, step b) of the method according to the invention is carried out, during which there is emission by the touch surface 12 of a series of at least one counting vibration 26 which can go up to a second number of vibrations. The counting vibrations 26 make it possible to code each character of the code, for example each digit from 0 to 9 of the code which comprises 4 digits. Each of these digits is coded by a determined number of vibrations. For example, the number of vibrations coding for a digit is equal to the digit that it codes. Thus, “9” is for example coded by nine vibrations. In the example described, it is intended to code “0” by 10 vibrations. Thus, to code a number, a series of at least one counting vibration is emitted, which in the example can go up to a second number of vibrations equal to 10. Thus, a third number of counting vibrations between 1 and 10 is emitted, and corresponding to the character to be entered.In one embodiment, and this to allow a malicious person to be deceived, . the number of vibration sequences can also be greater than 10. Thus, if the user lifts his finger at the 12th vibration, the number retained will be 2 (1 for 11 vibrations, 2 for 12, 3 for 13, etc.. Indeed, this makes it more difficult for a malicious person to guess the low-value numbers. Thus, the entropy is reinforced on all the numbers. The user can, for example, choose to stop at 23, to enter the number 3. Thus, in the case where a character of the code is a number, by number of counting vibrations which corresponds to a character of the code, we understand that the number can be equal to the number of vibrations or to the number of vibrations modulo 10.

[0039] In the example of [Fig. 3], the number "4" is entered by proceeding as follows. In steps VI, V2, V3 and V4, a counting vibration 26, 28, 30 and 32 are emitted respectively. As shown in [Fig. 4], the counting vibrations 26, 28, 30 and 32 are separated by a time interval D1, D2 and D3. The time intervals D1, D2 and D3 each take place during a contact step, respectively C2, C3 and C4, during which the contact 20 is maintained but there is no vibration.

[0040] When the number of counting vibrations emitted corresponds to the third number, here “4”, the user stops the contact 20, step P, in which the hands 16 are not in contact with the touch surface 12. Step c) of the method according to the invention is then carried out, during which the stopping of the contact 20 is detected after the third number of vibrations.

[0041] We then proceed to step d) of the method, that is to say that the third number of counting vibrations is recorded, here “4”, which corresponds to the character of the code entered, here “4”.

[0042] In one embodiment, and to increase the entropy of the code, the terminal can continue to emit a random number of vibrations, even after the user's finger is no longer in contact with the touch surface. These decoy vibrations are not perceived by the user; only the terminal knows when the user has removed his finger. Thus, the use of an accelerometer, stuck on the terminal, would not allow a malicious person to guess the entered code.

[0043] To enter the following characters of the code, we return to step a) up to step d), until a number of characters equal to the first number is recorded, 4 characters in the example.

[0044] As shown in [Fig.4], in the example the series of at least one counting vibration comprises at least two counting vibrations, more precisely four vibrations 26, 28, 30 and 32, and two consecutive counting vibrations are separated by a time interval D1, D2, D3 whose duration is random. Indeed, the durations D1, D2 and D3 are different from each other. Due to the interval of a random duration, the time required to capture a character and a person is ignored. Malicious software cannot identify a character by simply timing the pressure.

[0045] In the example, the counting vibrations 26, 28, 30 and 32 are separated by a time interval D1, D2, D3 of a duration of 1 second, 0.85 seconds and 3 seconds respectively.

[0046] In the example, during step b), each counting vibration 26, 28, 30 and 32 is emitted for a duration of between 0.8 and 1.6 seconds.

[0047] In the example, during step b), the amplitude of the counting vibration changes from 0 to 100%, then decreases to 0%. For better ergonomics, the amplitude of the vibration should change from 0 to 100% in the shortest possible time.

[0048] The steps of the input method are part of a payment method which also includes the following steps: - prior to step a), vocal statement of the transaction amount, - after step e), sending a voice message informing about the outcome of the entry.

[0049] The invention is not limited to the embodiments presented and other embodiments will become clear to those skilled in the art. It is in particular possible to implement the method without resorting to sensory calibration steps. List of references

[0050] 10: electronic payment terminal 12: touch surface 14: case 16: hands 18: finger 20: contact 22: first calibration vibration 24: second calibration vibration 26: first counting vibration 28: second counting vibration 30: third counting vibration 32: fourth counting vibration P: grip stage CC: contact step for calibration VC: vibration step during calibration Cl, C2, C3, C4: contact steps during counting VI, V2, V3, V4: vibration steps during counting

Claims

Claims

1. Method for entering on a touch-sensitive surface (12) a code comprising a first number of characters, preferably four characters, comprising the following steps: a) detecting a contact made by a user on the touch-sensitive surface (12), b) emitting by the touch-sensitive surface (12) a series of at least one counting vibration (26, 28, 30, 32) which can go up to a second number of counting vibrations, c) detecting the stopping of the contact after a third number of counting vibrations included between 1 and the second number, d) recording the third number of counting vibrations which corresponds to a character of the code, e) continuing at step a) up to step d), until recording a number of characters equal to the first number, method in which, when the series of at least one counting vibration comprises at least two counting vibrations (26, 28, 30, 32),two consecutive counting vibrations are separated by a time interval (Dl, D2, D3) whose duration is random.,

2. Input method according to claim 1, wherein the touch surface (12) is a touch surface of an electronic payment terminal (10).

3. Input method according to any one of claims 1 and 2, further comprising after step a) and before step b) a step during which a first vibration of constant amplitude (22) is emitted, called first calibration vibration, followed by a second vibration (24) whose amplitude is decreasing, called second calibration vibration.

4. A method of capturing according to any one of the preceding claims, wherein during step b), the counting vibrations (26, 28, 30, 32) are separated by a time interval (D1, D2, D3) of a duration ranging from 0.1 to 3 seconds, preferably 0.2 to 1.5 seconds.

5. A method of capturing according to any one of the preceding claims, wherein in step b), the counting vibrations (26, 28, 30, 32) are emitted at a frequency ranging from 100 to 1000 Hz, preferably 200 Hz.

6. A method of capturing according to any one of the preceding claims, wherein in step b), each counting vibration (26, 28, 30, 32) is emitted for a duration ranging from 0.1 to 2 seconds, preferably from 0.2 to 1 second.

7. A method of capturing according to any one of the preceding claims, wherein during step b), the amplitude of the counting vibration increases to a maximum, then decreases.

8. Input method according to any one of the preceding claims, in which at the end of step c) and before step e), the touch surface (12) emits at least one vibration.

9. Payment method comprising the steps of the method for entering a confidential code according to any one of claims 1 to 8, further comprising at least one of the following steps: - prior to step a), vocal statement of the amount of the transaction, - after step e), transmission of a vocal message providing information on the outcome of the entry.

10. Electronic payment terminal (10) comprising a touch surface (12) configured to implement the method of entering a code according to any one of claims 1 to 8, the touch surface (12) being equipped with a haptic actuator configured to execute step b) of the method.

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