Authentication for near field communications

A method for use in a near field communications system for authenticating, at a near field communications receiver, a user of a near field communications transmitter, the method comprising:

• receiving, at a receiver device that includes a first data receiver and a second data receiver, a signal comprising a first unique identifier from a near field communications transmitter, the first unique identifier indicating a predetermined pattern of movement of the near field communications transmitter, the predetermined pattern of movement specifying a pattern of movement in and out of range of the near field communications receiver and a length of time that the near field communications transmitter spends within range for communication with the near field communications receiver, the first data receiver using phase modulation and the second data receiver using amplitude modulation;
• measuring a signal strength of the received signal and storing the signal strength in a status register as one of three or more discrete levels;
• tracking a variation with time of the signal strength of the received signal and converting the variation with time into a second unique identifier that indicates an actual pattern of movement of the near field communications transmitter;
• comparing the received first unique identifier and the second unique identifier and outputting a signal indicating the result of the comparison;
• and
• authenticating the user if the signal indicating the result of said comparison indicates that the first unique identifier matches the second unique identifier.

A computer program product for use in a near field communications system for authenticating, at a near field communications receiver, a user of a near field communications transmitter, the computer program product comprising:

• a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising:
• computer readable program code configured for:
• receiving, at a receiver device that includes a first data receiver and a second data receiver, a signal comprising a first unique identifier from a near field communications transmitter, the first unique identifier indicating a predetermined pattern of movement of the near field communications transmitter, the predetermined pattern of movement specifying a pattern of movement in and out of range of the near field communications receiver and a length of time that the near field communications transmitter spends within range for communication with the near field communications receiver, the first data receiver using phase modulation and the second data receiver using amplitude modulation;
• measuring a signal strength of the received signal and storing the signal strength in a status register as one of three or more discrete levels;
• tracking a variation with time of the signal strength of the received signal and converting the variation with time into a second unique identifier that indicates an actual pattern of movement of the near field communications transmitter;
• comparing the received first unique identifier and the second unique identifier and outputting a signal indicating the result of the comparison;
• and
• authenticating the user if the signal indicating the result of said comparison indicates that the first unique identifier matches the second unique identifier.