Method and devices to secure the entry of an alphanumerical code, corresponding computer program product and storage means

1. A method comprising:

securing entry of an alphanumerical code, wherein securing entry comprises the following acts:

receiving from a secured server, by a first device,

at least one conversion table for converting at least one portion of said alphanumerical code into at least one portion of converted code, said at least one conversion table being a one-time conversion table; and

an identifier of the at least one conversion table;

displaying the at least one conversion table on a display of the first device;

converting, by using the at least one conversion table, the at least one portion of the alphanumerical code into the at least one portion of converted code;

entering the at least one portion of converted code, into a second device distinct from said first device, wherein the first device has access to the at least one conversion table and not to the at least one portion of converted code, and wherein the second device has access to the at least one portion of converted code and not to the at least one conversion table; and

transmitting the at least one portion of converted code and the identifier of the at least one conversion table to the secured server, the transmitting providing the secured server access to all information needed for reconstruction of the alphanumerical confidential code.

2. The method according to claim 1 , wherein the method comprises, before said act of transmitting, an act of encrypting the at least one portion of converted code.

3. The method according to claim 2 , wherein said act of encrypting also implements encrypting said identifier.

4. The method according to claim 1 , wherein said first and second devices are respectively a device of a merchant involved in a transaction necessitating entry of said alphanumerical code and a payment accessory connected to said device of said merchant.

5. The method according to claim 1 , wherein said first and second devices are respectively a payment accessory connected to a device of a merchant involved in a transaction necessitating entry of said alphanumerical code and said device of said merchant.

6. The method according to claim 1 , wherein transmitting comprises:

transmitting said at least one portion of converted code from the second device to the secured server, and transmitting said identifier from the first device to the secured server.

7. The method according to claim 1 , wherein transmitting comprises:

encrypting, by the second device, said at least one portion of converted code to produce an encrypted portion of converted code, transmitting said encrypted portion of converted code from the second device to the first device, and then transmitting the encrypted portion of the converted code and said identifier from the first device to the secured server.

8. The method according to claim 1 , wherein transmitting comprises:

transmitting said identifier from the first device to the second device, and then transmitting said at least one portion of converted code and the identifier from the second device to the secured server.

9. A computer-readable and non-transitory storage medium storing a computer program comprising a set of instructions executable by a computer or a processor to implement a method, wherein the method comprises:

securing entry of an alphanumerical code, wherein securing entry comprises the following acts:

receiving from a secured server, by a first device on which the instructions are executed,

at least one conversion table for converting at least one portion of said alphanumerical code into at least one portion of converted code, said at least one conversion table being a one-time conversion table; and

an identifier of the at least one conversion table;

displaying the at least one conversion table on a display of the first device;

receiving from a second device, distinct from said first device, an encrypted portion of converted code, which corresponds to the alphanumeric code converted to the at least one portion of converted code by the user and entered into and encrypted by the second device, wherein the first device has access to the at least one conversion table and not to the at least one portion of converted code unencrypted, and wherein the second device has access to the at least one portion of converted code and not to the at least one conversion table; and

transmitting at least said encrypted portion of converted code and the identifier to a secured server.

10. A system for securing entry of an alphanumerical code by a user, wherein the system comprises:

a first device, comprising:

a display;

means for receiving from a secured server:

at least one conversion table for converting at least one portion of said alphanumerical code into at least one portion of converted code, said information for converting being a one-time conversion table; and

an identifier of said at least one conversion table; and

means for displaying the at least one conversion table on the display; and

a second device, distinct from the first device and comprising:

means for entering at least said portion of converted code, converted by the user using said at least one conversion table displayed on the display of the first device, wherein the first device has access to the at least one conversion table and not to the at least one portion of converted code, and wherein the second device has access to the at least one portion of converted code and not to the at least one conversion table; and

means for transmitting the at least one portion of converted code and the identifier of the at least one conversion table to the secured server, the transmitting providing the secured server access to all information needed for reconstruction of the alphanumerical confidential code.