A first device transmits a first message to a second device as part of a challenge-response protocol in order to authenticate the second device. A power limited power supply coupled to the second device limits power consumption by the second device during the second device's challenge-response protocol calculations. The first device measures a response time of the second device during the challenge-response protocol. The authentication of the second device is based on the response time of the second device while it has limited power consumption.

Embodiments of welding and cutting systems are disclosed. A welding or cutting system includes a power source to provide electrical power for a welding or cutting process. The system includes a torch having a cryptographic device, and is to be used with the power source during the process and communicate with the power source. The cryptographic device is configured to receive an encryption key seeded by the power source during first time power-on initialization of the welding power source or after the torch is replaced. The cryptographic device is configured to store an unlock code associated with the power source, generate an encrypted message, which includes the unlock code, based on the encryption key, and communicate the encrypted message to the power source. The power source is configured to cease further operation unless the power source determines the torch to be a genuine manufacturer torch based on the unlock code.

A user requesting authentication is presented a keypad that includes multiple keys and respective keys include a character that is associated with a shape. Responsive to selection of a key, a first set of attributes is activated for selection. Responsive to determining a selection of an attribute from the first set of attributes, activating one or more additional sets of attributes associated with the first key. Responsive to determining a selection from the one or more additional sets of attributes, determining whether a selection of an additional key is made. Responsive to determining the selection of the additional key, activating for selection a first set of attributes and one or more additional sets of attributes of the additional key, and responsive to determining selections of keys and corresponding attributes associated with the selection of respective keys, determining the validity of the authentication code.

A user authentication device includes: a collection part collecting information of a user; a generation part generating a question for the user on the basis of the information of the user collected by the collection part and a skill model of the user; a presentation part presenting the question for the user generated by the generation part to the user; a reception part receiving, from the user, a response to the question presented by the presentation part; and a determination part determining authentication of the user on the basis of the response received by the reception part.

In some examples, a method comprises determining, at an electronic device having a first component of a first component type, a unique identifier associated with the first component. In some examples, in accordance with a determination that the unique identifier does not match the expected identifier of the component of the first component type in the electronic device, determining that the first component associated with the unique identifier satisfies one or more eligibility criteria. In some examples, in accordance with the determination that the first component associated with the unique identifier satisfies the one or more eligibility criteria, authenticating an association of the first component with the electronic device, including updating an installation counter associated with the first component, and updating the expected identifier for the component of the first type based on the unique identifier of the first component.

A method for signing up a user to a service for controlling at least one functionality in a vehicle (10) by means of a user terminal (20) comprises the following steps: —communicating a user identifier and an identifier associated with the vehicle (10) to a server (50); —having the server (50) authenticate an electronics unit (11) of the vehicle (10); —in the event of successful authentication, registering the user identifier and the identifier associated with the vehicle (10) in association with one another in the server (50).

A method comprises generating, during an enrollment process conducted in a controlled environment, a dark bit mask comprising a plurality of state information values derived from a plurality of entropy sources at a plurality of operating conditions for an electronic device, and using at least a portion of the plurality of state information values to generate a set of challenge-response pairs for use in an authentication process for the electronic device.

Techniques are disclosed relating to credential managers. In some embodiments, a computing device maintains a credential manager that stores, in a protected manner, a set of credentials for authenticating a user and metadata about the credentials. The computing device stores an instance of the metadata externally to the credential manager. The computing device uses the externally stored metadata to determine whether the set of credentials includes a particular credential associated with a service and, in response to determining that the set of credentials includes the particular credential, displays an indication of the particular credential. In some embodiments, the computing device receives a selection of the displayed indication by the user and, in response to the selection, sends a request for the particular credential to the credential manager.

A request for use of an application programming interface (API) is received. Context associated with the request is determined. Based on the context, a challenge is generated, which can be used for determining whether to permit the use of the API. A response to the challenge is received. Based on the response, the request can be facilitated for using the API.

A method of securing a computer resource against unauthorized access includes sending, by a processing device, a challenge data structure to a user computer system, obtaining a user response representing at least one user-selected image from the plurality of images, and providing access to the computer resource for the user computer system based on whether the at least one user-selected image is consistent with the one or more correct images. The challenge data structure defines a challenge to be presented to a user of the user computer system. The challenge involves selecting one or more correct images that conform to one or more aspects of a challenge key from a plurality of images based on a relative orientation with respect to one another of elements within the plurality of images.