A method for authenticating a user equipped with a mobile device in a system comprising a website requiring the generation of a usage token J, a server comprising a digital identity account directory for users, characterised in that it comprises at least the following steps: o upon request from a user, the website requests the generation of a usage token J having a time-limited validity duration for the account of the user; o the request to generate a usage token is transmitted to a digital identity account directory that verifies the status of the digital identity account of the user; o in the event that the status of the digital identity account is valid, a token generation system generates a usage token with a validity duration, encrypts a one-time password OTP with a public key of the user and sends a request to transmit a usage token to the mobile device of the user; o the user decides to accept or to refuse (114, 115) this request to transmit a usage token J; o when the user accepts the transmission of a usage token J, the user enters an authentication code on their mobile device, this entry generating a request to decrypt the encrypted one-time password OTP to a digital identity identification application implemented on a secure element, which decrypts the OTP password and transmits it so that it can be displayed on a device for entering the information of the user and, at the same time, the digital identity identification application verifies the temporal validity of the generated token; o the user enters the OTP on the website; o the website verifies the OTP using the OTP generated with the site public key on the system for generating a usage token J, the OTP having been received and decrypted by the site, and, at the same time, the website verifies the temporal validity of the generated usage token; o accepting or refusing the access of the user to the website according to the result of this verification. o upon request from a user, the website requests the generation of a usage token J having a time-limited validity duration for the account of the user; o the request to generate a usage token is transmitted to a digital identity account directory that verifies the status of the digital identity account of the user; o in the event that the status of the digital identity account is valid, a token generation system generates a usage token with a validity duration, encrypts a one-time password OTP with a public key of the user and sends a request to transmit a usage token to the mobile device of the user; o the user decides to accept or to refuse (114, 115) this request to transmit a usage token J; o when the user accepts the transmission of a usage token J, the user enters an authentication code on their mobile device, this entry generating a request to decrypt the encrypted one-time password OTP to a digital identity identification application implemented on a secure element, which decrypts the OTP password and transmits it so that it can be displayed on a device for entering the information of the user and, at the same time, the digital identity identification application verifies the temporal validity of the generated token; o the user enters the OTP on the website; o the website verifies the OTP using the OTP generated with the site public key on the system for generating a usage token J, the OTP having been received and decrypted by the site, and, at the same time, the website verifies the temporal validity of the generated usage token; o accepting or refusing the access of the user to the website according to the result of this verification.