Patent ID: 8443432

Claim:
A method for calibrating temperature float of a one time password token comprising a crystal oscillator, in which the one time password token generates a dynamic factor according to a time value and a time step for changing the dynamic factor, and generates and displays a one time password according to the dynamic factor, wherein the method comprises steps of measuring an current ambient temperature of the one time password token at one interval of a first predetermined time by the one time password token itself; retrieving a data table in terms of the measured temperature and obtaining a corresponding characteristic value which is an oscillator frequency of the crystal oscillator of the measured temperature by the one time password token; computing a time deviation of the crystal oscillator according to the oscillator frequency of the measured temperature; and if a accumulated time deviation is larger than or equal to a predetermined value, calibrating a current time value inside the one time password token according to the oscillator frequency at a other interval of a second predetermined time by the one time password token.