Boot Validation in Imaging Devices

Abstract

A boot validation system and method may be used in a computer system to validate boot code before allowing the computer system to execute the boot code. In particular, a secure hash algorithm may be used to compute a hash value of the boot code and the computed hash value may be compared to a preprogrammed hash value stored in a secure non-volatile device. If the hash values match the boot code may be validated and the system may then be allowed to execute the boot code. Once the boot code is validated, the boot code may be executed to validate other code (e.g., firmware) in the computer system. In an exemplary embodiment, the boot validation system and method may be used in an imaging device, such as a printer.

1 . A system for boot validation in an image forming device including at least one central processing unit (CPU), comprising:
 a firmware storage device including firmware, said firmware including at least boot code;   a secure non-volatile storage device storing a preprogrammed hash value corresponding to said boot code; and   logic configured to hold at least said CPU in reset in response to a power on signal to prevent said CPU from executing said boot code upon powering on said image forming device, to retrieve said boot code, to compute a hash value of said boot code, to retrieve said preprogrammed hash value, to compare said computed hash value to said preprogrammed hash value, and to allow said image forming device to execute said boot code if said computed hash value matches said preprogrammed hash value.   
   
   
       2 . The system of  claim 1  wherein said boot code includes tamper detection code configured to validate other firmware. 
   
   
       3 . The system of  claim 1  further comprising an application specific integrated circuit (ASIC) including said logic. 
   
   
       4 . The system of  claim 1  further comprising a system application specific integrated circuit (ASIC) and a boot validation device coupled to said system ASIC, wherein said boot validation device includes said logic. 
   
   
       5 . The system of  claim 1  wherein said firmware storage device is for storing said boot code together with other executable code including firmware other than boot code. 
   
   
       6 . The system of  claim 1  wherein said logic is configured to inhibit operation of at least one component of said image forming device if said computed hash value does not match said preprogrammed hash value. 
   
   
       7 . The system of  claim 1  wherein said image forming device is one of a printer, a fax device, a copier, or a combination thereof. 
   
   
       8 . The system of  claim 1  wherein said system is contained in a cartridge configured for use in the image forming device. 
   
   
       9 . The system of  claim 1  further comprising a boot validation device including said logic. 
   
   
       10 . The system of  claim 1  wherein said firmware storage device includes programmable non-volatile memory. 
   
   
       11 . An imaging device including at least one central processing unit (CPU), comprising:
 a print engine; and   a controller configured to operate said print engine and to control image forming operations, said controller comprising:
 a firmware storage device including firmware, said firmware including at least boot code; 
 a secure non-volatile storage device storing a preprogrammed hash value corresponding to said boot code; and 
 logic configured to hold at least said CPU in reset in response to a power on signal to prevent said CPU from executing said boot code upon powering on said imaging device, to retrieve said boot code, to compute a hash value of said boot code, to retrieve said preprogrammed hash value, to compare said computed hash value to said preprogrammed hash value, and to allow said imaging device to execute said boot code if said computed hash value matches said preprogrammed hash value. 
   
   
   
       12 . The imaging device of  claim 11  wherein said controller comprises an application specific integrated circuit (ASIC), said ASIC including said logic. 
   
   
       13 . The imaging device of  claim 11  wherein said controller comprises a system application specific integrated circuit (ASIC) and a boot validation device coupled to said ASIC, said boot validation device including said logic. 
   
   
       14 . The imaging device of  claim 11  wherein said controller comprises said CPU, and said CPU is coupled to said logic, wherein said logic is configured to prevent said CPU from executing instructions. 
   
   
       15 . The imaging device of  claim 11  wherein said firmware storage device is for storing said boot code together with other executable code including firmware other than boot code. 
   
   
       16 . The imaging device of  claim 11  wherein said logic is configured to inhibit operation of at least one component of said imaging device if said computed hash value does not match said preprogrammed hash value. 
   
   
       17 . The imaging device of  claim 11  wherein said imaging device is one of a printer, a fax device, a copier, or a combination thereof. 
   
   
       18 . A computer program product residing on a computer readable medium having a plurality of instructions stored thereon which, when executed by a processor, cause the processor to perform a boot validation method in an image forming device including at least one central processing unit (CPU), the method comprising:
 holding at least said CPU in reset in response to a power on signal to prevent said CPU from executing at least boot code upon powering on said image forming device;   retrieving said boot code from a firmware storage device;   computing a hash value of said boot code;   retrieving a preprogrammed hash value from a secure non-volatile device;   comparing said computed hash value with said preprogrammed hash value; and   allowing said image forming device to execute the boot code if said computed hash value matches said preprogrammed hash value.   
   
   
       19 . The computer program product of  claim 18  wherein the method further comprises executing said boot code to validate other executable code. 
   
   
       20 . The computer program product of  claim 18  wherein said product is contained in an image forming apparatus. 
   
   
       21 . The computer program product of  claim 18  wherein said product is contained in an image forming device cartridge. 
   
   
       22 . The computer program product of  claim 18  wherein said firmware storage device is for storing said boot code together with other executable code including firmware other than boot code.