Sensing scheme for low power refram-based physical unclonable functions

A method of establishing secure communication between a server and client computing device, the client computing device including an array of unformed memory cells in which formation of breakable conductive paths may be induced, the method comprising:

• performing an enrollment process on the client computing device, the enrollment process comprising:
• selecting a probe current value, the probe current value being sufficiently low such that when current is passed through the memory cells of the array of unformed memory cells, the cells do not exhibit conductive path formation;
• applying the selected probe current value to the cells of the array of unformed memory cells, and measuring their resistance;
• categorizing all measured cells having a resistance above a first threshold in a first category, and categorizing all measured cells having a resistance below a second threshold in a second category;
• selecting an interrogation current value,
• measuring the resistance of the cells categorized in the second category at the interrogation current value;
• storing the measured resistance of the cells categorized in the second category and addresses of the measured cells in a database.