Patent attributes
A method in a memory system having a security device and a serial external electrically erasable read-only memory (EEPROM) is disclosed. The method includes accepting N bits of a command prefix and matching the bits to command filtering rules. Upon matching the prefix to a command filtering rule, the method may perform a filter action associated with the matched rule. When the command prefix is for a destructive command prefix that can modify data in the EEPROM, the filter action may convert the command into a non-destructive command and inspect it for authentication. The converted command may be output to the external EEPROM without security processing in the security device and the external EEPROM may return read data without outputting. When the command prefix is for a non-destructive command prefix, the command may be allowed to pass through the external EEPROM unchanged without performing security processing in the security device.
