Data security in an information processing device

Abstract

A device is provided that combines data protection for stored data with ease of use in cases where data encrypted using a public key is received and stored. Public key encrypted data received by a data receiver module ( 50 ) is decrypted by a PKI encryption module 52 using a private key. A job controller module ( 51 ) then determines whether or not protection is necessary for this data based on processing instructions etc. for the data. When data protection is necessary, this data is encrypted by an internal key encryption module ( 56 ) and stored in HDD ( 16 ). The internal key encryption module 56 performs encryption using an internal key generated from a device serial number of a device. The internal key differs from a PKI public key in having no expiration date and not requiring updating, and can also be used to decrypt old data stored on the HDD ( 16 ).

What is claimed is:  
     
         1 . An information processing device comprising: 
 a data input interface for inputting encrypted data;    a decryption module for decrypting encrypted data inputted by the data input interface using a decryption key forming a pair with a first encryption key used to encrypt the data;    an encryption module for encrypting data decrypted by the decryption module using a second encryption key different from the first encryption key; and    a storage device for storing data encrypted by the encryption module.    
     
     
         2 . The information processing device of  claim 1 , wherein 
 an expiration date is not set for the second encryption key.    
     
     
         3 . The information processing device of  claim 1 , wherein 
 the data input interface also inputs unencrypted data, and    the encryption module also encrypts unencrypted data input by the data input interface.    
     
     
         4 . The information processing device of  claim 1 , further comprising: 
 a key generator for generating the second encryption key.    
     
     
         5 . The information processing device of  claim 4 , further comprising: 
 volatile memory; and    a memory controller for storing the second encryption key in the volatile memory.    
     
     
         6 . The information processing device of  claim 4 , wherein 
 the key generator generates the second encryption key using information characteristic to the device itself.    
     
     
         7 . The information processing device of  claim 4 , wherein 
 the key generator generates the second encryption key when power to the device is turned on.    
     
     
         8 . The information processing device of  claim 4 , further comprising: 
 a media reader capable of being installed with a removable portable storage media storing key generation parameters for reading a key generation parameter stored on the installed portable storage media, wherein    the key generator generates the second encryption key using the key generation parameter.    
     
     
         9 . The information processing device of  claim 4 , further comprising: 
 a security level setting module for setting a security level for the information processing device, wherein    the key generator generates the second encryption key of a key length corresponding to the security level set at the security level setting module.    
     
     
         10 . The information processing device of  claim 4 , further comprising: 
 a region setting module for receiving settings for a region where the device is to be used, wherein    the key generator generates the second encryption key of a key length corresponding to the region set at the region setting module.    
     
     
         11 . The information processing device of  claim 1 , further comprising: 
 a media reader capable of being installed with a removable portable storage media storing the encryption key, wherein    the encryption module reads the second encryption key from the portable storage media installed in the media reader and performs encryption.    
     
     
         12 . The information processing device of  claim 1 , equipped with a plurality of the storage devices, and having second encryption keys corresponding to each storage device, wherein the encryption module performs encryption using the second encryption key corresponding to storage device decided by a data storage destination.  
     
     
         13 . The information processing device of  claim 1 , having encryption keys corresponding to each user using the device, wherein 
 the encryption module performs encryption using an encryption key for the user corresponding to the data.    
     
     
         14 . The information processing device of  claim 1 , further comprising: 
 deciding means for deciding whether or not to encrypt data inputted by the data input interface, wherein    the encryption module encrypts data decided upon for encryption by the deciding means.    
     
     
         15 . The information processing device of  claim 14 , wherein 
 the deciding means decides to encrypt when data inputted by the data input interface is encrypted.    
     
     
         16 . The information processing device of  claim 1 , further comprising a printer for decrypting and printing data stored in the storage device.  
     
     
         17 . A method for storing data inputted to an information processing device, comprising the steps of: 
 inputting encrypted data;    decrypting encrypted data inputted using a decryption key forming a pair with a first encryption key used to encrypt the data;    encrypting decrypted data using a second encryption key different from the first encryption key; and    storing data encrypted using the second encryption key.    
     
     
         18 . The information processing device of  claim 17 , further comprising a step of: 
 storing the second encryption key in the volatile memory.