A computing system comprising: - a first computing device comprising: - at least one sensor able to capture biometric data; - at least one first processing logic; - at least one second computing device comprising at least one second processing logic; - a first communication link between said first computing device and said second computing device; - at least one third computing device comprising at least one third processing logic; - a second communication link between said second computing device and said third computing device; - a third communication link between said first computing device and said third computing device; wherein: - said first processing logic is configured to: - store a private key and a certificate comprising a digital identifier of a user and a public key corresponding to the private key - send to said third device a request to access a service; - send to said third device the signed certificate comprising the digital identifier of the user; - use said sensor to capture biometric data of the user currently using the first computing device; - said third processing logic is configured to: - send to said second device a request for verifying the validity of the certificate; - said second processing logic is configured to: - verify the validity of the certificate; - said first processing logic is configured to perform a comparison of said biometric data and reference biometric data and sending the output to the second computing device; or sending the obtained biometric data to the second computing device in which case said second processing logic is configured to perform a comparison of said biometric data and reference biometric data - if the output of said comparison is positive and the validity of the certificate is verified, the second processing logic is configured to send to the third computing device an indication that the certificate is valid, and the third processing logic is configured to authenticate the user and grant access to the service. - a first computing device comprising: - at least one sensor able to capture biometric data; - at least one first processing logic; - at least one sensor able to capture biometric data; - at least one first processing logic; - at least one second computing device comprising at least one second processing logic; - a first communication link between said first computing device and said second computing device; - at least one third computing device comprising at least one third processing logic; - a second communication link between said second computing device and said third computing device; - a third communication link between said first computing device and said third computing device; - said first processing logic is configured to: - store a private key and a certificate comprising a digital identifier of a user and a public key corresponding to the private key - send to said third device a request to access a service; - send to said third device the signed certificate comprising the digital identifier of the user; - use said sensor to capture biometric data of the user currently using the first computing device; - store a private key and a certificate comprising a digital identifier of a user and a public key corresponding to the private key - send to said third device a request to access a service; - send to said third device the signed certificate comprising the digital identifier of the user; - use said sensor to capture biometric data of the user currently using the first computing device; - said third processing logic is configured to: - send to said second device a request for verifying the validity of the certificate; - send to said second device a request for verifying the validity of the certificate; - said second processing logic is configured to: - verify the validity of the certificate; - verify the validity of the certificate; - said first processing logic is configured to perform a comparison of said biometric data and reference biometric data and sending the output to the second computing device; or sending the obtained biometric data to the second computing device in which case said second processing logic is configured to perform a comparison of said biometric data and reference biometric data - if the output of said comparison is positive and the validity of the certificate is verified, the second processing logic is configured to send to the third computing device an indication that the certificate is valid, and the third processing logic is configured to authenticate the user and grant access to the service.