E-fuses for storing security version data

Abstract

Methods and devices that may be utilized in systems to dynamically update a security version parameter used to encrypt secure data are provided. The version may be maintained in persistent storage located on a device implementing the encryption, such as a system on a chip (SOC). The persistent storage does not require battery backing and, thus, the cost and complexity associated with conventional systems utilizing battery backed storage may be reduced.

1 . A device for encrypting blocks of data to be stored in memory external to the device, comprising:
 first persistent storage elements for storing a security version parameter;   second persistent storage elements for storing master key data;   an encryption engine configured to encrypt secure blocks of data to be stored in the external memory, wherein at least one of: the encrypted secure blocks or an integrity check value generated therefore are affected by the security version parameter; and   a mechanism for modifying the first persistent storage elements to update the security version parameter without modifying previously modified first persistent storage elements.   
     
     
         2 . The device of  claim 1 , wherein the first persistent storage elements comprise electrically programmable fuses. 
     
     
         3 . The device of  claim 1 , wherein the second persistent storage elements comprise electrically programmable fuses. 
     
     
         4 . The device of  claim 1 , wherein the second persistent storage elements comprise laser fuses. 
     
     
         5 . The device of  claim 1 , further comprising a validation component configured to:
 validate that a security version parameter used to encrypt a retrieved block of secure data, or generate an integrity check value therefor, is the same as the security version parameter maintained in the first persistent storage elements.   
     
     
         6 . The device of  claim 1 , wherein the device is a central processing unit. 
     
     
         7 . The device of  claim 6 , wherein the device is a central processing unit on a gaming system. 
     
     
         8 . The device of  claim 7 , wherein the secure data contains key information used to decrypt a game program.