Authentication using analog signal challenge

Abstract

A method of determining authenticity of a component in an imaging device includes generating an analog signal as an authentication challenge to the component. The method further includes generating, by the component, a response to the authentication challenge by converting the analog signal into one or more digital values and capturing a derivative of the one or more digital values as the response. Authenticity of the component is determined by comparing the response with an expected response.

1 . A supply item for installation in an imaging device, comprising:
 a housing; and   a security device chip connected to the housing, the security device chip for receiving an authentication challenge including an analog signal when the supply item is installed in the imaging device, wherein when the security device chip receives the authentication challenge the security device chip is operative to convert the analog signal into one or more digital values and take a derivative of the one or more digital values.   
     
     
         2 . The supply item of  claim 1 , wherein the analog signal that is received by the security device chip has randomness in at least one of amplitude, frequency, and duration. 
     
     
         3 . The supply item of  claim 1 , wherein the security device chip is further operative to provide back to the imaging device the derivative thereby indicating an authentication response of the security device chip to the authentication challenge. 
     
     
         4 . The supply item of  claim 1 , wherein the security device chip is further operative to convert the analog signal into the one or more digital values during a measurement interval. 
     
     
         5 . The supply item of  claim 4 , wherein the measurement interval begins with a programmable start condition of the security device chip. 
     
     
         6 . The supply item of  claim 1 , wherein the derivative is one of an arithmetical and logical transformation of the one or more digital values. 
     
     
         7 . The supply item of  claim 1 , wherein the security device chip is further operative to provide the derivative to a second supply item installed in the imaging device. 
     
     
         8 . The supply item of  claim 1 , further including an analog circuit on the security device chip. 
     
     
         9 . The supply item of  claim 8 , wherein the analog circuit is operative to convert any digital values into a second analog signal. 
     
     
         10 . The supply item of  claim 9 , further including a second analog circuit on the security device chip for converting the analog signal into the one or more digital values. 
     
     
         11 . The supply item of  claim 8 , wherein the analog circuit is operative to convert the analog signal into the one or more digital values. 
     
     
         12 . The supply item of  claim 1 , wherein the supply item is a toner cartridge and the housing contains toner. 
     
     
         13 . A supply item for installation in an imaging device, comprising:
 a housing; and   a security device chip connected to the housing, the security device chip for generating on an analog circuit available to the security device chip an authentication challenge including a randomly generated analog signal, wherein when the supply item is installed in the imaging device the security device chip is operative to send the randomly generated analog signal to the imaging device and receive a response thereto.   
     
     
         14 . The supply item of  claim 13 , wherein the security device chip is further operative to receive back from the imaging device an arithmetic or logical derivative and compare the derivate to parameters stored in memory available to the security chip device. 
     
     
         15 . The supply item of  claim 13 , wherein the analog circuit is on the security device chip for converting digital values to analog signals and vice versa. 
     
     
         16 . The supply item of  claim 13 , further including first and second analog circuits on the security device chip for one of converting digital values to analog signals and converting analog signals to digital values. 
     
     
         17 . A supply item for installation in an imaging device, comprising:
 a housing;   a security device chip connected to the housing, the security device chip having access to available memory and an analog circuit, the security device chip operative to 1) generate one or more random numbers, 2) identify one or more parameters stored in the memory based on the one or more random numbers, and 3) generate by the analog circuit, a random analog signal based on the one or more parameters.   
     
     
         18 . The supply item of  claim 17 , wherein the security device chip is further operative to send the random analog signal to the imaging device. 
     
     
         19 . The supply item of  claim 17 , wherein the security device chip is further operative to generate the random analog signal that is random in at least one of amplitude, frequency, and duration. 
     
     
         20 . The supply item of  claim 17 , further including a second analog circuit available to the security device chip, wherein the analog circuit and the second analog circuit available to the security device chip either convert digital values to analog signals or vice versa.