Method for securing input of personal identification number and corresponding device

Abstract

The invention relates to a method (100) for securing the entry of a personal identification code element, referred to as a PIN code, on a mobile terminal (TM) configured to communicate with a server (S), said method comprising the following steps implemented by said mobile terminal (TM):-receiving (101) a random sequence of basic instructions from the server (S), the basic instruction random sequence is configured to present a drawing displayed on a touch screen (ET) of the mobile terminal (TM) after execution of the basic instruction random sequence by a processing module (MT) of the mobile terminal (TM), the displayed rendering corresponds to at least one of an input area of a virtual keyboard (CV) and a PIN code element (ECP) associated with said input area (ZS),-executing (102) said random sequence of basic instructions.

Description

[0001] The present invention relates to the field of payment applications, and in particular to the field of software applications configured to convert a commercial mobile terminal facing the public into a payment terminal.

[0002] It is known to convert a commercial mobile terminal (e.g., a smartphone, in particular of the smartphone type) intended for non-professional customers into a payment terminal using a software application that implements a method configured to ensure the confidentiality of a personal identification number (PIN) entered on the mobile terminal to authenticate the payment card holder.

[0003] To this end, it is more common to mix the relative positions of the areas for entering different digits of the PIN code on the terminal screen so that the relative positions for a new transaction are different from those for previous transactions. Said positions are randomly determined by a server independent of the mobile terminal; thus, these arrangements make it possible to defend against attacks via secondary channels (such as monitoring terminal sensors, for example the accelerometer or gyroscope, in order to guess the digits entered for the PIN code).

[0004] However, a disadvantage of this known solution is that it is not sufficient to counter the threat of an attacker who monitors and analyzes the payment application and / or the data stream exchanged between the payment application and the server during the execution of the payment application and / or the data stream exchanged between the payment application and the server on the mobile terminal to identify the area of ​​the PIN code and the corresponding position of the digits, thereby determining the presentation of the virtual keyboard for entering the PIN code digits.

[0005] Therefore, the present invention aims to propose a solution to all or some of these problems.

[0006] To this end, the invention relates to a method for protecting the entry of a personal identification code element, known as a PIN code, on a mobile terminal configured to communicate with a server, comprising the following steps implemented by the mobile terminal:

[0007] - receiving a random sequence of basic instructions from a server, the random sequence of basic instructions being configured to present a drawing displayed on a touch screen of the mobile terminal after the random sequence of basic instructions is executed by a processing module of the mobile terminal, the displayed drawing corresponding to at least one of an input area of ​​the virtual keyboard and a PIN code element associated with the input area,

[0008] -Executes a random sequence of basic instructions.

[0009] According to one embodiment, the present invention comprises one or more of the following features, alone or in a technically acceptable combination.

[0010] According to one embodiment, the random sequence of basic instructions is generated by a step implemented by the server to randomly sort the initial sequence of basic instructions generated by the server, and the initial sequence is also configured to present the displayed drawing on the touch screen of the mobile terminal after the processing module of the mobile terminal executes the initial sequence of basic instructions.

[0011] According to these provisions, fraudulent interception of the basic sequence by a third party will not allow him / her to determine the basic sequence of initial instructions from which the random sequence originates; the random ordering in fact makes it possible to distribute the information in the sequence, so that the fraudulent capture of a segment of the basic sequence of initial instructions contains less information than the segment of the basic sequence of initial instructions. Also according to these provisions, like the initial sequence, the basic sequence of randomization does not contain direct references to the input fields and the PIN code elements associated with them.

[0012] According to one embodiment, the random sequence of basic instructions includes at least one instruction encoded by a server, and the method includes a decoding step before executing the random sequence of basic instructions to generate at least one decoded instruction of the random sequence of basic instructions.

[0013] Under these regulations, fraudulent monitoring of data transmissions between servers and mobile terminals by third parties will be more difficult to exploit.

[0014] According to one embodiment, at least one decoded instruction in the random sequence of basic instructions is a function of at least one other previously decoded instruction in the random sequence of basic instructions.

[0015] According to one embodiment, during the step of executing a decoded elementary instruction sequence, at least one decoded instruction in said instruction sequence is erased after having been executed and before the execution of the next instruction in the sequence.

[0016] According to these provisions, the copy of the mobile terminal's internal memory will not allow the attacker to return to the complete basic instruction sequence.

[0017] According to one aspect, the invention also relates to a method for protecting the entry of a personal identification code element, known as a PIN code, on a mobile terminal configured to communicate with a server, comprising the following steps implemented by the server:

[0018] - generating a random sequence of basic instructions, the random sequence of basic instructions being configured to present a drawing displayed on a touch screen of the mobile terminal after the processing module of the mobile terminal executes the random sequence of basic instructions, the displayed drawing corresponding to at least one of an input area of ​​the virtual keyboard and a PIN code element associated with the input area,

[0019] -Sending the basic instruction random sequence to the mobile terminal.

[0020] According to one embodiment, the method includes one or more of the following features, alone or in combination.

[0021] According to one embodiment, the method further comprises the step of generating an initial sequence of basic instructions, the initial sequence of basic instructions being configured to present the drawing displayed on the touch screen of the mobile terminal after the processing module of the mobile terminal executes the initial sequence of basic instructions, the initial ordering of the initial sequence of basic instructions corresponding to the layout of the input area and the PIN code elements associated with the input area on the screen of the mobile terminal;

[0022] a step of generating a random sequence of basic instructions, wherein the random sequence of basic instructions includes a random ordering of an initial sequence of basic instructions to randomly modify the initial ordering of the initial sequence of basic instructions, and the random ordering generates a random sequence of basic instructions;

[0023] According to these provisions, fraudulent interception of the basic instruction sequence by a third party will not allow him / her to determine the initial sequence; the random ordering makes it possible to distribute the information in the sequence, so that the fraudulent capture of the basic instruction segment contains less information than the initial sequence segment. Also according to these provisions, the basic instruction initial sequence does not contain direct references to the input field and the PIN code elements associated with the input field.

[0024] According to these regulations, fraudulent interception of parts of the basic command sequence by a third party will not allow him / her to determine the elements of the entered PIN code.

[0025] According to one embodiment, the method further includes a step of encoding the basic instruction random sequence before the transmission step, wherein the encoding step generates at least one encoded instruction associated with at least one instruction of the basic instruction random sequence, and the at least one encoded instruction is a function of the at least one instruction and at least one other instruction of the basic instruction random sequence, and the at least one other instruction is located before the at least one instruction in the basic instruction random sequence.

[0026] Under these regulations, it will be much more difficult to determine the initial sequence of basic instructions through fraudulent monitoring by a third party.

[0027] According to one aspect, the present invention also relates to a mobile terminal configured to protect the input of a personal identification code element called a PIN code, the mobile terminal comprising a receiving module configured to receive a random sequence of basic instructions from a server, a touch screen, and a processing module configured to execute the basic instructions of the random sequence, the random sequence of basic instructions originating from a server randomly modifying an initial ordering of an initial sequence of basic instructions previously generated by the server, the execution of the random sequence of basic instructions having the effect of drawing a virtual keyboard, an input area of ​​the virtual keyboard, and at least one of a PIN code element associated with the input area on the touch screen.

[0028] According to one embodiment, the processing module comprises a decoding module configured to generate at least one decoded instruction of the random sequence of basic instructions, the at least one decoded instruction of the random sequence of basic instructions being a function of at least one previous decoded instruction in the random sequence of basic instructions.

[0029] According to one embodiment, the processing module is configured to erase at least one decoded instruction from the sequence of instructions after execution by the processing module and before execution of a next instruction in the sequence.

[0030] According to another aspect, the present invention also relates to a server configured to protect the input of a personal identification code element called a PIN code on a mobile terminal, the server being configured to communicate with the mobile terminal, the server including a generation module configured to generate an initial sequence of basic instructions, the initial sequence of basic instructions being configured to draw at least one of a virtual keyboard, an input area of ​​the virtual keyboard, and a PIN code element associated with the input area on the touch screen of the mobile terminal when the initial sequence of basic instructions is executed by a processing module of the mobile terminal, the initial ordering of the initial sequence of basic instructions corresponding to the layout of the input area and the PIN code element associated with the input area of ​​the virtual keyboard on the screen of the mobile terminal, the generation module being further configured to randomly modify the initial order of the initial sequence of basic instructions and generate a random sequence of basic instructions, the server also including a transmission module configured to send the random sequence of basic instructions to the mobile terminal.

[0031] According to one embodiment, the generation module also includes an encoding module, which is configured to generate at least one encoded instruction associated with at least one instruction in the basic instruction random sequence, and the at least one encoded instruction is a function of at least one instruction and at least one other instruction of the basic instruction random sequence, and the at least one other instruction is located before the at least one instruction in the basic instruction random sequence.

[0032] According to another aspect, the present invention also relates to a system configured to secure the input of a personal identification code element called a PIN code on a mobile terminal according to any of the above embodiments, the system comprising a server according to any of the above embodiments and a mobile terminal.

[0033] For a better understanding, embodiments and / or implementations of the present invention are described with reference to the accompanying drawings, which, by way of non-limiting examples, represent embodiments and implementations of the apparatus and / or method according to the present invention, respectively. The same reference numerals in the drawings represent similar elements or elements with similar functions.

[0034] [ Figure 1 ] is a schematic diagram of elements of a system configured to implement the method according to the present invention to ensure the input of elements of a PIN code on a virtual keyboard drawn on a touch screen of a mobile terminal communicating with a server.

[0035] [ Figure 2 ] shows examples of virtual keyboards drawn with input areas of different shapes.

[0036] [ Figure 3 ] is a schematic diagram of a sequence of steps implemented by a mobile terminal and a server.

[0037] To make it more difficult for an attacker to determine the presentation of the virtual keyboard used to enter PIN code elements and subsequently infer the numbers entered via touch input on the virtual keyboard input area, it is necessary to delete the high-level instructions (of the type {"draw key," "draw number") configured in the mobile terminal's payment application for drawing the virtual input keyboard input area on the mobile terminal's screen and replace them with a series of low-level instructions for virtual input keyboard drawing operations, such as "draw polygon." The low-level instruction sequence configured for the virtual input keyboard drawing operations is calculated and randomly modified by the server and then sent to the mobile terminal application in a sequential and encrypted manner. This method does not reveal the nature, object, and parameters of the drawing operations, thereby ensuring that only the mobile terminal's payment application has the rules for interpreting the low-level instruction sequence sent to it.

[0038] As a supplement and extra precaution, instructions are immediately executed and deleted one after another on the fly as they are received from the server.

[0039] According to these provisions, analysis of the instruction stream sent by the server to the application on the mobile terminal, in particular concerning breaking the encryption used to protect the data sent, will not reveal the presentation of the virtual input keyboard on the mobile terminal screen.

[0040] In fact, according to these provisions, the virtual input keyboard is not defined in terms of high-level operations related to displaying input areas located on the screen and numbers associated with these input areas, but is defined in terms of a sequence of basic operations in graphics drawing that does not directly expose information about the locations of the input areas and numbers associated with these input areas unless the sequence of basic operations is decoded or the graphics memory is directly "dumped" to obtain the image rendered by executing the entire sequence of basic operations.

[0041] This method can also draw input areas of different sizes or touch virtual keyboard keys, such as Figure 2 As shown in the example.

[0042] Figure 1 is a schematic diagram of elements of a system comprising a mobile terminal TM and a server S, the system being configured to communicate and implement the method according to the invention to ensure the entry of elements of a PIN code on a virtual keyboard CV drawn on the touch screen ET of the mobile terminal TM.

[0043] Typically, the elements of a PIN are numbers, such as Figure 1 As shown, elements of the PIN may include any other graphical symbols accepted by the input application.

[0044] Each element of the PIN code is associated with an input area ZS of the touch screen ET of the mobile terminal TM, so the user selects the PIN code element associated with the input area ZS, such as a number, by touching the input area ZS. Typically, the input area ZS is represented by a simple and uniform shape on the touch screen ET, such as a square or rectangle, as shown in the figure. However, the input area ZS can also have various shapes or be different from each other, such as Figure 2 shown.

[0045] A mobile terminal TM is a device intended for the public, comprising a touch screen ET and a processing module MT configured to execute instruction sequences (in particular software applications) and to communicate with a remote server S. The mobile terminal is preferably a smartphone; it may also be a tablet or a laptop, for example.

[0046] The mobile terminal TM particularly comprises a receiving module MRx configured to receive a random sequence of basic instructions from a server S; the random sequence of basic instructions is generated, for example, by the server based on an initial sequence of basic instructions, which is itself generated by the server S. The initial sequence of basic instructions is configured to be executable on a processing module MT of the mobile terminal TM and, when the initial sequence of basic instructions is executed by the processing module MT of the mobile terminal TM, draws a virtual keyboard CV, an input area ZS of the virtual keyboard CV, and / or a PIN code element ECP associated with the input area ZS on the touch screen ET of the mobile terminal TM. The server S comprises a generating module MG configured to generate a random sequence of basic instructions (202) from the initial sequence of basic instructions, for example by randomly modifying an initial order of the initial sequence of basic instructions. The random sequence of basic instructions is still configured to draw a virtual keyboard CV, an input area ZS of the virtual keyboard CV, and / or a PIN code element ECP associated with the input area ZS on the touch screen ET of the mobile terminal TM when the random sequence of basic instructions is executed by the processing module MT of the mobile terminal TM.

[0047] Random ordering allows for information to be distributed within the sequence, making it difficult to exploit fraudulently capturing the basic instruction segments by including dispersed information until all information is available. Consequently, fraudulent interception of the basic instruction sequence by a third party will not allow them to determine the initial sequence. Furthermore, the initial sequence of basic instructions does not include direct references to the input fields and PIN code elements associated with them. Consequently, fraudulent interception of the basic instruction sequence by a third party will not allow them to determine the input fields and PIN code elements that are the subject of the instruction sequence.

[0048] Optionally, the processing module MT includes a decoding module MD configured to decode all or part of the basic instruction random sequence encoded by the encoding module ME of the server S before the server S sends the basic instruction random sequence to the mobile terminal TM. Optionally, the encoding module ME encodes only a portion of the basic instruction random sequence; in this case, the decoding module MD of the processing module MT of the mobile terminal TM decodes only this portion of the basic instruction random sequence.

[0049] For example, the encoding of the elementary instructions in the elementary instruction random sequence is a function of at least one other elementary instruction preceding the elementary instruction in the elementary instruction random sequence. In this case, the generation of the decoded elementary instruction will be a function of at least one other decoded elementary instruction preceding the elementary instruction in the elementary instruction random sequence.

[0050] To enhance the security of the encoding / decoding operations, the processing module MT of the mobile terminal can be configured to erase at least one decoded instruction from the instruction sequence after the processing module MT executes it and before the execution of the next instruction in the sequence. According to these provisions, the copy of the internal memory of the mobile terminal (TM) will not allow an attacker to return to the complete basic instruction sequence; therefore, it will be more difficult to determine the original basic instruction sequence through fraudulent eavesdropping by a third party.

[0051] According to one aspect, the invention relates to a server S configured to protect the entry of a personal identification code element, known as a PIN code, on a mobile terminal, the server being configured to communicate with the mobile terminal and comprising a generation module MG configured to generate a random sequence of basic instructions (202); the random sequence of instructions being generated, for example, by the server S from an initial sequence of basic instructions, the initial sequence of basic instructions itself being generated by the server S. The initial sequence of basic instructions being configured to be executable on a processing module MT of a mobile terminal TM and, when executed by the processing module MT of the mobile terminal TM, drawing a virtual keyboard CV, an input zone ZS of the virtual keyboard CV and / or a PIN code element ECP associated with this input zone ZS on the touch screen ET of the mobile terminal TM; the initial ordering of the initial sequence of basic instructions corresponding to the layout of the input zone ZS of the virtual keyboard CV and the PIN code element ECP associated with this input zone ZS of the virtual keyboard CV on the screen of the mobile terminal of the virtual keyboard CV. According to this particular embodiment of the step 202 of generating a random sequence of elementary instructions, the generation module MG is further configured to randomly modify the initial ordering of the initial sequence of elementary instructions and thus generate said random sequence of elementary instructions.Other embodiments of the step 202 of generating a random sequence of elementary instructions are conceivable.

[0052] The server S finally comprises a transmission module MTx configured to send a random sequence of elementary instructions to the mobile terminal TM.

[0053] The server's generation module MG also includes an encoding module ME, which is configured to encode at least one instruction in the random sequence of basic instructions, wherein the at least one encoded instruction is a function of the at least one instruction and at least one other instruction in the random sequence of basic instructions, and the at least one other instruction is located before the at least one instruction in the random sequence of basic instructions.

[0054] According to another aspect, the invention relates to a system comprising a server S according to any of the previously described embodiments and a mobile terminal TM according to any of the previously described embodiments.

[0055] According to one aspect, the present invention relates to a method 100 implemented by a mobile terminal TM according to any of the previously described embodiments, the method 100 comprising the following steps, see Figure 3 :

[0056] - receiving (101) a random sequence of basic instructions from the server S; this random sequence of basic instructions is generated, for example, by a step implemented by the server S of randomly sorting 201 an initial sequence of basic instructions generated by the server S itself, both the initial sequence of basic instructions and the random sequence of basic instructions being configured to draw, on the touch screen ET of the mobile terminal TMTM, the same graphic representation of the virtual keyboard, the input area of ​​the virtual keyboard CV and / or the PIN code element ECP associated with the input area ZS, when the initial sequence of basic instructions or the random sequence of basic instructions is executed on the mobile terminal TM by the processing module MT of the mobile terminal TM,

[0057] - Execute the random sequence of basic instructions (102).

[0058] Optionally, before executing the random sequence of basic instructions, the method 100 further includes a decoding step 101bis to generate at least one decoded instruction of the random sequence of basic instructions.

[0059] Specifically, at least one decoded instruction in the random sequence of basic instructions may be a function of at least one other previously decoded instruction in the random sequence of basic instructions.

[0060] More specifically, during step 102 of executing the decoded basic instruction sequence, at least one decoded instruction in the instruction sequence is erased after execution and before the next instruction in the sequence is executed. Thus, the copy of the internal memory of the mobile terminal TM will not allow an attacker to return to the complete basic instruction sequence.

[0061] According to another aspect, the invention also relates to a method 200 for protecting the entry of a personal identification code element, known as a PIN code, on a mobile terminal TM configured to communicate with a server S, comprising the following steps implemented by the server S:

[0062] - generating (202) a random sequence of basic instructions configured to render, after execution by the processing module MT of the mobile terminal TM, a drawing displayed on the touch screen ET of the mobile terminal TM, the displayed drawing corresponding to the virtual keyboard, the input zone of the virtual keyboard CV and / or the PIN code element ECP associated with the input zone ZS,

[0063] The generation 202 of the random sequence of basic instructions may, for example, comprise a step 201 of generating an initial sequence of basic instructions, the initial sequence of basic instructions being configured to present said drawing displayed on the touch screen ET of the mobile terminal TM after the processing module MT of the mobile terminal TM executes the initial sequence of basic instructions, the initial ordering of the initial sequence of basic instructions corresponding to the layout of the virtual keyboard, the input area ZS of the virtual keyboard and / or the PIN code elements associated with the input area ZS of the virtual keyboard on the screen of the mobile terminal TM;

[0064] The step 202 of generating a random sequence of basic instructions according to this exemplary embodiment particularly includes a random ordering of the initial sequence of basic instructions to randomly modify the initial ordering of the initial sequence of basic instructions, the random ordering generating the random sequence of basic instructions;

[0065] - Sending (203) the basic instruction random sequence to the mobile terminal TM.

[0066] According to these provisions, fraudulent interception of the basic instruction sequence by a third party will not allow him / her to determine the initial sequence; the random ordering in fact makes it possible to distribute the information in the sequence so that the fraudulent capture of the basic instruction segment contains less information than the initial sequence segment. Also according to these provisions, the basic instruction initial sequence does not include direct references to the input fields and the PIN code elements associated with the input fields.

[0067] According to these regulations, fraudulent interception of parts of the basic command sequence by a third party will not allow him / her to determine the elements of the entered PIN code.

[0068] To enhance the security of the method, the method further includes a step 202bis of encoding the random sequence of basic instructions before the transmission step 203. The encoding step 202bis generates at least one encoded instruction associated with at least one instruction in the random sequence of basic instructions. The at least one encoded instruction is a function of the at least one instruction and at least one other instruction in the random sequence of basic instructions, the at least one other instruction preceding the at least one instruction in the random sequence of basic instructions. Therefore, it becomes more difficult for a third party to fraudulently eavesdrop on the initial sequence of basic instructions.

Claims

1. A method (100) for protecting the entry of a personal identification code element, known as a PIN code, on a mobile terminal (TM) configured to communicate with a server (S), said method comprising the following steps implemented by said mobile terminal (TM): - receiving (101) a random sequence of basic instructions from a server (S), said random sequence of basic instructions being configured to render, after execution of said random sequence of basic instructions by a processing module (MT) of said mobile terminal (TM), a drawing displayed on a touch screen (ET) of said mobile terminal (TM), said displayed drawing corresponding to at least one of an input zone of a virtual keyboard (CV) and a PIN code element (ECP) associated with said input zone (ZS), -Executing (102) said random sequence of elementary instructions.

2. According to the method (100) of claim 1, the random sequence of basic instructions is generated by a step of randomly sorting (202) the initial sequence of basic instructions generated by the service (S) implemented by the server (S), and the initial sequence is also configured to present the displayed drawing on the touch screen (ET) of the mobile terminal (TM) after the initial sequence of basic instructions is executed by the processing module (MT) of the mobile terminal (TM).

3. The method (100) according to any one of claims 1 or 2, wherein: The random sequence of basic instructions comprises at least one instruction encoded by the server (S), and the method (100) comprises a decoding step (101bis) before executing the random sequence of basic instructions to generate at least one decoded instruction of the random sequence of basic instructions.

4. The method (100) according to any one of claims 1 to 3, wherein: At least one decoded instruction in the random sequence of basic instructions is a function of at least one other instruction previously decoded in the random sequence of basic instructions.

5. The method (100) according to claim 4, wherein: During the step (102) of executing the decoded elementary instruction sequence, at least one decoded instruction in the instruction sequence is erased after having been executed and before the next instruction in the sequence is executed.

6. A method (200) for protecting the entry of a personal identification code element, known as a PIN code, on a mobile terminal (TM) configured to communicate with a server (S), said method comprising the following steps implemented by said server (S): - generating (202) a random sequence of basic instructions, said random sequence of basic instructions being configured to render, after execution of said random sequence of basic instructions by a processing module (MT) of said mobile terminal (TM), a drawing displayed on a touch screen (ET) of the mobile terminal, said displayed drawing corresponding to at least one of an input zone of a virtual keyboard (CV) and a PIN code element (ECP) associated with said input zone (ZS), - Sending (203) said random sequence of basic instructions to said mobile terminal (TM).

7. The method (200) according to the preceding claim, further comprising a step (201) of generating an initial sequence of basic instructions, said initial sequence of basic instructions being configured to render said drawing displayed on the touch screen (ET) of said mobile terminal (TM) after said initial sequence of basic instructions is executed by a processing module (MT) of said mobile terminal (TM), an initial ordering of said initial sequence of basic instructions corresponding to a layout of said input zone (ZS) and said PIN code elements (ZS) associated with said input zone on the screen of said mobile terminal (TM); The step (202) of generating the random sequence of basic instructions includes a random sorting of the initial sequence of basic instructions to randomly modify the initial sorting of the initial sequence of basic instructions, and the random sorting generates the random sequence of basic instructions.

8. The method (200) according to any one of claims 6 or 7, further comprising a step (202bis) of encoding the basic instruction random sequence before the transmission step (203), wherein the encoding step (202bis) generates at least one encoded instruction associated with at least one instruction of the basic instruction random sequence, wherein the at least one encoded instruction is a function of the at least one instruction and at least one other instruction in the basic instruction random sequence, and the at least one other instruction is located before the at least one instruction in the basic instruction random sequence.

9. A mobile terminal (TM) configured to protect the input of a personal identification code element called a PIN code, the mobile terminal (TM) comprising a receiving module (MRx) configured to receive a random sequence of basic instructions from a server (S), a touch screen (ET) and a processing module (MT) configured to execute the random sequence of basic instructions, the random sequence of basic instructions originating from a random modification of an initial sequence of basic instructions previously generated by the server (S), the execution of the random sequence of basic instructions having the effect of drawing on the touch screen (ET) at least one of a virtual keyboard (CV), an input area (ZS) of the virtual keyboard and a PIN code element (ECP) associated with the input area (ZS).

10. The mobile terminal (TM) according to claim 9, wherein: The processing module (MT) comprises a decoding module (MD) configured to generate at least one decoded instruction of the random sequence of basic instructions, the at least one decoded instruction of the random sequence of basic instructions being a function of at least one previous decoded instruction in the random sequence of basic instructions.

11. A server (S) configured to protect the input of a personal identification code element called a PIN code on a mobile terminal (TM), the server being configured to communicate with the mobile terminal (TM), the server comprising a generating module (MG) configured to generate an initial sequence of basic instructions, the initial sequence of basic instructions being configured to draw a virtual keyboard, an input area (ZS) of the virtual keyboard (CV) and an input area (ZS) associated with the virtual keyboard (CV) on a touch screen (ET) of the mobile terminal (TM) when the initial sequence of basic instructions is executed by a processing module (MT) of the mobile terminal (TM). The server further comprises a transmission module (MTx) configured to send the random sequence of basic instructions to a mobile terminal (TM). The server further comprises a transmission module (MTx) configured to send the random sequence of basic instructions to the mobile terminal (TM). The server further comprises a transmission module (MTx) configured to send the random sequence of basic instructions to the mobile terminal (TM).

12. The server (S) according to claim 11, wherein The generation module (MG) further comprises an encoding module (ME) configured to generate at least one encoded instruction associated with at least one instruction of the random sequence of basic instructions, the at least one encoded instruction being a function of the at least one instruction and at least one other instruction of the random sequence of basic instructions, the at least one other instruction being located before the at least one instruction in the random sequence of basic instructions.

13. A system configured to protect the entry of a personal identification code element, called a PIN code, on a mobile terminal (TM) according to any one of claims 9 or 10, the system comprising a server according to any one of claims 11 or 12 and the mobile terminal (TM).

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