External interface access control for medical systems

A medical system configured to be used in association with an external memory storage device comprising a file system, the medical system comprising:

• an input/output data port configured to receive a signature file comprising at least one file and a plurality of signature files from the external memory storage device;
• and
• a medical device maintaining and configured to employ an operating system capable of reading medical system data from and writing medical system data to said external memory storage device via the input/output data port;
• wherein the plurality of signature files in the signature file on the external memory storage device file is calculated using a plurality of hashing algorithms, the at least one file deemed acceptable for use within the medical system by a party, each signature value readable by the medical system and used to determine whether each file on the external memory storage device is permitted to have access to medical resources within the medical system;
• wherein the plurality of hashing algorithms are selected by the party based on a size and number of files anticipated to be provided in the signature file;
• and further wherein the medical device is configured to:
• decrypt the signature value using at least one of the hashing algorithms to produce a decrypted signature value;
• compare the decrypted signature value against most recent known decrypted signature values provided to the medical system and established by the party;
• and
• determine, based on the decrypted signature value of each file, whether each file is permitted to be used in the medical system while providing continued medical system operation wherein each permitted file is afforded access to medical device computational resources and each file not permitted is denied access to medical device computational resources;
• wherein altering one from a group consisting of the file and the signature file on the external memory storage devices results in the medical system not verifying the file and denying access by the file to medical system computational resources.

A method for protecting medical system resources available on a medical device from access by unauthorized files stored in an external memory storage device, the method comprising:

• inspecting, using the medical device, a plurality of signature values associated with one file located on said external memory storage device, wherein each signature value is calculated using one of a plurality of hashing algorithms and all signature values for the one file are provided with the one file on the external memory storage device, the one file deemed acceptable for use within the medical device by a party;
• and
• verifying, using the medical device, one file stored within the external memory storage device is a known software application asset by causing the medical device to decrypt the signature value associated with the one file stored within the external medical device using one of the plurality of hashing algorithms, producing a decrypted signature value, and comparing the decrypted signature value with most recent known decrypted signature values established and provided to the medical system from the party;
• wherein the plurality of hashing algorithms are selected by the party based on a size and number of files anticipated to be provided in the signature file;
• wherein verifying the at least one file results in continued medical device operation wherein the medical device affords access by a verified acceptable file to medical device resources and denies access by an unverified unacceptable file to medical system resources, and wherein altering one from the group consisting of the file and the signature value on the external memory storage device results in the medical system not verifying the file and denying access by the file to medical system resources.