Method for securing the security data of a bank payment card associated with a bank account, which security data are static and comprise the number of said card, identification data of the holder of said card, the expiry date of said card, and a cryptogram, which bank card number and which cryptogram are made up of multiple digits and/or letters, said method comprising the steps of: - only partially inscribing the security data in an intelligible manner on said card so that security data are concealed, said concealed data being formed by: multiple digits and/or letters of the number of said card and/or at least one piece of identification data of the cardholder and/or at least one element of the expiry date and/or at least one digit and/or letter of the cryptogram, - transmitting, to the holder of the card only, a means for disclosing the concealed data, - hiding the concealed data, which are visible on the card, among multiple pieces of data, characterized in that the method comprises the following steps: - arranging the data in a grid, - visibly inscribing the grid on one face of the card, the means for disclosing the concealed data comprising a concealed-data revealer, which takes the virtual form of an augmented reality image generated from a computer application installed on a mobile terminal of the holder of the card, which revealer image is displayed on a screen of said terminal, superimposed on a real image of the grid which is also displayed on said screen, the real image of the card being captured by the optical acquisition means of the mobile terminal, the concealed data being pre-recorded in the memory of the mobile terminal. - only partially inscribing the security data in an intelligible manner on said card so that security data are concealed, said concealed data being formed by: multiple digits and/or letters of the number of said card and/or at least one piece of identification data of the cardholder and/or at least one element of the expiry date and/or at least one digit and/or letter of the cryptogram, - transmitting, to the holder of the card only, a means for disclosing the concealed data, - hiding the concealed data, which are visible on the card, among multiple pieces of data, characterized in that the method comprises the following steps: - arranging the data in a grid, - visibly inscribing the grid on one face of the card, the means for disclosing the concealed data comprising a concealed-data revealer, which takes the virtual form of an augmented reality image generated from a computer application installed on a mobile terminal of the holder of the card, which revealer image is displayed on a screen of said terminal, superimposed on a real image of the grid which is also displayed on said screen, the real image of the card being captured by the optical acquisition means of the mobile terminal, the concealed data being pre-recorded in the memory of the mobile terminal. - arranging the data in a grid, - visibly inscribing the grid on one face of the card, the means for disclosing the concealed data comprising a concealed-data revealer, which takes the virtual form of an augmented reality image generated from a computer application installed on a mobile terminal of the holder of the card, which revealer image is displayed on a screen of said terminal, superimposed on a real image of the grid which is also displayed on said screen, the real image of the card being captured by the optical acquisition means of the mobile terminal, the concealed data being pre-recorded in the memory of the mobile terminal.