Authentication using magnetic field based on current drawn by security device

Abstract

Systems and methods for determining authenticity of a security device of a component in an imaging device includes receiving, by the security device, an authentication challenge including one or more commands and executing, by the security device, the one or more commands in response to receiving the authentication challenge. A magnetic field profile is generated based on current drawn by the security device from a power source while the security device is executing the one or more commands, the generated magnetic field profile indicating an authentication response of the security device to the authentication challenge for use in determining authenticity of the security device.

1 . In an imaging system having an imaging device and a supply item, each with a security device chip and having access to memory, a method of determining authenticity of the supply item installed and connected to the imaging device, either or both the imaging device and supply item having a conductor for passing current to the security device chips, comprising:
 generating an authentication challenge to the supply item, the challenge having one or more commands for execution by the supply item;   transmitting the challenge to the supply item;   receiving the challenge at the supply item;   executing the one or more commands of the challenge at the supply item, the executing drawing the current over the conductor and generating a magnetic field; and   characterizing the magnetic field, thereby indicating an authentication response to the challenge.   
     
     
         2 . The method of  claim 1 , wherein the characterizing includes measuring a strength of the magnetic field. 
     
     
         3 . The method of  claim 1 , further including transmitting the authentication response from the supply item to the imaging device. 
     
     
         4 . The method of  claim 3 , further including receiving the response at the imaging device; and comparing at the imaging device the response with an expected response stored in the memory of the imaging device to determine authenticity of the supply item. 
     
     
         5 . The method of  claim 1 , further including placing a magnetometer in proximity to the conductor to measure the magnetic field. 
     
     
         6 . The method of  claim 1 , further including generating a magnetic field profile based on the characterization of the magnetic field. 
     
     
         7 . The method of  claim 6 , further including using the magnetic field profile as the authentication response. 
     
     
         8 . The method of  claim 1 , wherein the imaging system further includes another supply item having another security device chip with access to memory and the imaging device transmits the challenge to the another supply item. 
     
     
         9 . The method of  claim 8 , further including transmitting the authentication response from the supply item to the another supply item. 
     
     
         10 . The method of  claim 9 , further including receiving the response at the another supply item; and comparing at the another supply item the response with an expected response stored in the memory available to the another security device chip of the another supply item to determine authenticity of the supply item. 
     
     
         11 . The method of  claim 1 , further including providing the imaging system with a power source from which the security device chips draw current through the conductor. 
     
     
         12 . The method of  claim 1 , further including toner in a housing of the supply item and securing the security device chip of the supply item to the housing. 
     
     
         13 . The method of  claim 1 , further including providing a power bus between the security device chips of the imaging device and the supply item. 
     
     
         14 . The method of  claim 1 , wherein the imaging device generates the authentication challenge. 
     
     
         15 . The method of  claim 14 , wherein the authentication challenge is transmitted from the imaging device to the supply item. 
     
     
         16 . The method of  claim 1 , wherein the imaging system further includes another supply item having another security device chip with access to memory and the another security device chip said generates the authentication challenge. 
     
     
         17 . The method of  claim 16 , wherein the another supply item transmits the challenge to the supply item. 
     
     
         18 . The method of  claim 5 , further including providing the magnetometer with either or both hall effect or magnetoresistance sensors. 
     
     
         19 . The imaging system of  claim 5 , further including triggering a start condition from which the magnetometer is configured to measure the magnetic field during a measurement duration. 
     
     
         20 . In an imaging system having an imaging device and first and second toner cartridges, each of the imaging device and the toner cartridges having a security device chip and having access to memory, a method of determining authenticity of the toner cartridges installed and connected to the imaging device, at least one of the imaging device and the toner cartridges having a conductor for passing current to the security device chips, comprising:
 generating in the imaging device an authentication challenge to the toner cartridges, the challenge having one or more commands for execution by the security device chips of the toner cartridges;   transmitting the challenge from the imaging device to both the toner cartridges;   receiving the challenge at said both the toner cartridges;   executing the one or more commands of the challenge at the security device chips of both the toner cartridges, the executing drawing the current over the conductor and generating a plurality of unique magnetic fields;   measuring the unique magnetic fields, thereby indicating authentication responses from said both toner cartridges to the challenge for the imaging device to determine the authenticity of said both toner cartridges.