Patent ID: 7516479
Filing Date: 2009-04-07
Classification: G06Q,G07F

Abstract:
1. A data communication apparatus having a memory space, the data communication apparatus managing the memory space by separating the memory space into one or more file systems, the apparatus comprising: controlling means for holding a separating authority key and managing the access to the file system in the memory space, wherein said separating authority key is not known to any of a plurality of service providers that share said memory space; and a first file system allocated to a first service provider in the memory space, the first file system holding an issuer key of the first service provider, wherein said issuer key is only known to its associated service provider; wherein, upon receiving, from a second service provider requesting an allocation of a new file system, a separate package generated by encrypting, using the issuer key of the first service provider, a data block containing a separate element package generated by encrypting an issuer key of the second service provider using the separating authority key and information on the new file system, the first file system decrypts the received separate package using the issuer key of the first service provider and retrieves the separate element package and the information on the new file system, and wherein the controlling means decrypts the separate element package using the separating authority key, retrieves the issuer key of the second service provider, separates a free area of the memory space in accordance with the information on the new file system, and allocates the separated memory area to a second file system holding the issuer key of the second service provider.