Network security device and method

#This invention relates to a technique for achieving a high level of physical security in a network security device such as would be used with a portable computer, a computer terminal or a Personal Digital Assistant (PDA) to connect to a network and obtain secure service from that network.

#The power of a computing device, such as a personal computer, data terminal or even a Personal Data Assistant (collectively referred hereinafter as “a network peripheral device”) improves dramatically when such device is connected to other devices across a network to allow information sharing. Such a network may take the form of a simple Local Area Network (LAN), Wide Area Network, Corporate Intranet, the Intranet or combination of such networks. In many instances, the services, resources and/or data accessed or transmitted through this network are sensitive in that a breach of authenticity or privacy of the services, resources or information would have economic or other undesirable consequences for the users of the network.

#Security is achieved by the use of a combination of software and hardware measures. Software employing a variety of cryptographic techniques is used to encrypt and/or authenticate the information exchanged through the network while hardware-based physical security measures guarantee that the cryptographic keys and the software using these keys remain uncorrupted, private and trustworthy. The software and cryptographic techniques used depend on the services, resources and information accessed through the network; for example, a network security device that supports Virtual Private Networking (VPN) functionality will have software that implements IPsec, Point-to-Point Tunneling Protocol (PPTP) or some other VPN protocol. This software will use cryptographic keys in the way specified by the VPN protocol in use to encrypt and/or authenticate all information flowing to and fro the network.

#FIG. 1 illustrates partially cut-away perspective view of a security device in accordance with a preferred embodiment of the present invention;

#FIG. 1 illustrates a security mechanism 10 in accordance with a preferred embodiment of the invention for permitting a user (not shown) to establish a secure communications session between a network peripheral device 12 and a communications network 14 via a security gateway 15. The network peripheral device 12 can take the form of a computer terminal, personal computer or a Personal Data Assistant (PDA), while the network 14 may comprise Virtual Private Network (VPN) accessed directly, or through an intermediate network (not shown). In the illustrated embodiment, the security mechanism 10 is a network card that provides VPN functionality and that has the configuration of a Personal Computer Memory Card International Association (PCMCIA) package for receipt in a PCMCIA slot 16 within the network peripheral device 12. Alternatively, the security mechanism 10 could take on other configurations and could offer different functionality without departing from the spirit and scope of the invention.

#To facilitate the establishment of a secure session, the security mechanism 10 includes at least one immutable memory element 18 in the form of a Read Only Memory (ROM) element that stores information (software and support files) that remains fixed for all times (i.e., for each and every communications session). In the illustrated embodiment, the memory element 18 bears the designation “Security ROM” because it stores security application software (including bootstrap) code that initiates the operation of the security mechanism 10. Further, the security ROM 18 also generates at random the private key(s) required by the security mechanism 10 to perform its security functions including user and device authentication. (This ensures that the private keys used by different network peripheral devices remain independent from each other and that the security device cannot be forced to use keys known to an attacker.)

#As an adjunct to Security ROM 18, the security mechanism 10 may also include a write-once ROM 20 for storing information written into the ROM during manufacture of the security mechanism. Such information may include additional bootstrap code as well as any upgrade that occurred subsequent to the manufacture of the Security ROM 18. (To the extent that either of the ROMs 18 and 20 have an upgrade capability, only the upgrade management software should have the capability of modifying the software in each ROM. Further, any application that loads either ROM should be signed by the manufacturer and the signature verified prior to writing any data.)