Abstract: The present invention relates to the field of authentication of users of services over a computer network, more specifically within the paradigms of federated authentication or single sign-on. A known technique consists of associating different trust levels to different authentication mechanisms, wherein the respective trust levels give access to different information resources, notably to provide the possibility to protect more sensitive resources with a stronger form of authentication. The present invention provides a mechanism to allow the trust level to decrease without re-authenticating with the single sign on system, down to the level at which it is no longer sufficient to obtain access to a desired resource. Only then, the user needs to reauthenticate.

Abstract: The present patent application discloses a USB token that advantageously mimics a human interface device such as a keyboard in interacting with a host computer, thus removing the need for pre-installation of a dedicated device driver. This is accomplished by requiring the host computer to direct the input of the attached human interface devices of the keyboard type, including the USB token, exclusively to the program interacting with the USB token, by using cryptographic algorithms based on a shared secret, which require less data to be transferred than PKI-based algorithms, and by employing an efficient encoding scheme that minimizes the time needed to exchange information with the USB token, and minimizes the probability of generating ambiguity with input that might legitimately be generated by other attached human interface devices.

Abstract: The present invention relates to the field of authentication of users of services over a computer network, more specifically within the paradigms of federated authentication or single sign-on. A known technique consists of associating different trust levels to different authentication mechanisms, wherein the respective trust levels give access to different information resources, notably to provide the possibility to protect more sensitive resources with a stronger form of authentication. The present invention provides a mechanism to allow the trust level to decrease without re-authenticating with the single sign on system, down to the level at which it is no longer sufficient to obtain access to a desired resource. Only then, the user needs to reauthenticate.

Abstract: The present patent application discloses a USB token that advantageously mimics a human interface device such as a keyboard in interacting with a host computer, thus removing the need for pre-installation of a dedicated device driver. This is accomplished by requiring the host computer to direct the input of the attached human interface devices of the keyboard type, including the USB token, exclusively to the program interacting with the USB token, by using cryptographic algorithms based on a shared secret, which require less data to be transferred than PKI-based algorithms, and by employing an efficient encoding scheme that minimizes the time needed to exchange information with the USB token, and minimizes the probability of generating ambiguity with input that might legitimately be generated by other attached human interface devices.