METHOD FOR ESTABLISHING A RANDOM NUMBER FOR SECURITY AND ENCRYPTION, AND A COMMUNICATIONS APPARATUS

摘要

A communications apparatus includes a mobile device. The apparatus includes a receiver for receiving at the mobile device a plurality of signals carrying information including received signals which provides randomly varying data related to location of the mobile device. The apparatus includes a random number generator which generates a random number as a function of the data. The apparatus includes acryptographickey generator which generates a cryptographic key using the random number. A method to establish at a mobile device a random number for cryptographic operations includes the steps of receiving at the mobile device a plurality of signals carrying information including received signals which provides randomly varying data related to location of the mobile device. There is the step of estimating signal entropy for at least one of the received signals in dependence of location where the signals are received by the mobile device. There is the step of selecting the at least one entropy estimated signal having estimated entropysatisfying a predetermined property. There is the step of generating from the at least one entropy estimated signal the random number.