Authentication using analog signal challenge

Abstract

Determining authenticity of a component in an imaging device includes generating an analog signal as an authentication challenge to the component. The component then generates 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 being configured to generate an authentication challenge and send to itself a randomly generated analog signal when the housing is installed in the imaging device.   
     
     
         2 . The supply item of  claim 1 , wherein the security device chip is configured to receive and convert the randomly generated analog signal a digital signal correlating to the analog signal. 
     
     
         3 . The supply item of  claim 2 , wherein the security device chip is configured to compute an arithmetic or logical derivative of the digital signal. 
     
     
         4 . The supply item of  claim 3 , wherein the security device chip is configured to send to itself and receive the derivative of the digital signal. 
     
     
         5 . The supply item of  claim 4 , wherein the security device chip is configured to generate an expected response for comparison to the derivative. 
     
     
         6 . The supply item of  claim 5 , wherein the security device chip is configured to dynamically compute or read from available memory the expected response. 
     
     
         7 . The supply item of  claim 6 , wherein the security device chip is configured to compare the expected response to the derivative to authenticate or not the supply item. 
     
     
         8 . The supply item of  claim 7 , wherein the security device chip is configured to execute a statistical correlation algorithm having a predetermined threshold. 
     
     
         9 . The supply item of  claim 1 , wherein the randomly generated analog signal has randomness in at least one of signal amplitude, signal frequency, and signal duration. 
     
     
         10 . The supply item of  claim 1 , wherein the security device chip includes a first analog circuit. 
     
     
         11 . The supply item of  claim 10 , wherein the first analog circuit is operative to convert any digital value into a second analog signal. 
     
     
         12 . The supply item of  claim 10 , wherein the security device chip further includes a second analog circuit in communication with the first analog circuit for converting any analog signal into corresponding digital signals. 
     
     
         13 . The supply item of  claim 1 , wherein the housing contains toner for imaging media in the imaging device. 
     
     
         14 . The supply item of  claim 1 , wherein the security device chip connects to and communicates with a control of the imaging device over a shared bus. 
     
     
         15 . The supply item of  claim 14 , wherein the shared bus carries data in a bidirectional manner over a two-wire serial bus. 
     
     
         16 . The supply item of  claim 15 , wherein one wire of the two-wire serial bus carries clocking signals. 
     
     
         17 . The supply item of  claim 1 , wherein the security device chip includes an input buffer circuit or an analog to digital converter circuit. 
     
     
         18 . The supply item of  claim 1 , wherein the security device chip is further configured to send the randomly generated analog signal to a controller of the imaging device when the housing is installed in the imaging device. 
     
     
         19 . The supply item of  claim 1 , wherein the security device chip is further configured to send the randomly generated analog signal to a second security device of another supply item installed in the imaging device when the housing is installed in the imaging device. 
     
     
         20 . A toner cartridge for installation in an imaging device, comprising:
 a housing having toner; and   a security device chip connected to the housing, the security device chip being configured for self-authentication when the housing is installed in the imaging device, including being configured to generate an authentication challenge and an authentication response thereto and to send to the imaging device and back to the security device chip of the toner cartridge a randomly generated analog signal and a response to the analog signal including a digital signal corresponding thereto and an arithmetic or logical derivative thereof for comparison to a dynamically-generated or stored-in-memory expected response thereby authenticating or not the security device chip of the toner cartridge.