Techniques are disclosed relating to secure data storage. In various embodiments, a mobile device includes a wireless interface, a secure element, and a secure circuit. The secure element is configured to store confidential information associated with a plurality of users and to receive a request to communicate the confidential information associated with a particular one of the plurality of users. The secure element is further configured to communicate, via the wireless interface, the confidential information associated with the particular user in response to an authentication of the particular user. The secure circuit is configured to perform the authentication of the particular user. In some embodiments, the mobile device also includes a biosensor configured to collect biometric information from a user of the mobile device. In such an embodiment, the secure circuit is configured to store biometric information collected from the plurality of users by the biosensor.