Abstract: Methods and systems for providing lime information in intermittently powered devices that are batteryless and operate purely on harvested energy (also referred to as zero power devices). The method of these teachings for improving security of zero power devices includes determining an estimate of time using a decay of data in a volatile device, and deciding whether to respond to a query based on the estimate of time.

Abstract: The present disclosure provides a method and a system for characterizing and identifying an electronic device using a physical fingerprint. In one aspect, the characterizing method includes determining the physical fingerprint of a test device using selected memory cells of an SRAM array in the test device, and storing data associated with the physical fingerprint in a database. The physical fingerprint of the test device includes data retention voltages respectfully corresponding to the selected memory cells. In one aspect, the identifying method includes characterizing a test device using data retention voltages of selected memory cells in the test device as a physical fingerprint of the test device, and comparing the physical fingerprint of the test device with a predetermined fingerprint of a target device.

Abstract: Methods and systems for providing lime information in intermittently powered devices that are batteryless and operate purely on harvested energy (also referred to as zero power devices). The method of these teachings for improving security of zero power devices includes determining an estimate of time using a decay of data in a volatile device, and deciding whether to respond to a query based on the estimate of time.

Abstract: Windowed backward key rotation. A user is provided information that allows determining a limited number of previous keys in a series of keys from a later key in the series. A key in the series is generated, based at least in part on the information provided to the user. The key in the series is provided to the user. The user determines at least one key in the limited number of previous keys in the series by applying the information to the key in the series.

Abstract: A method and system for relating cryptographic keys. A method includes providing to a user a private share related to a key. The method also includes generating a new key based on a previous version of the key and publishing a rotation catalyst. The new version of the key is determinable based on the key rotation catalyst and the private share. Further, former versions of the key are determinable based on the key rotation catalyst.

Abstract: A method and system for relating cryptographic keys. A method includes providing to a user a private share related to a key. The method also includes generating a new key based on a previous version of the key and publishing a rotation catalyst. The new version of the key is determinable based on the key rotation catalyst and the private share. Further, former versions of the key are determinable based on the key rotation catalyst.