Systems and methods for managing state
AssigneeIntertrust Technologies Corporation
InventorStephen G. Mitchell
Life of this patent
Estimating the term…
Abstract
The disclosure relates to systems and methods for managing state using relatively small assistance from protected hardware. Obfuscated code segments may communicate with supporting protected hardware, store encrypted state values in main memory, and/or communicate via secure channels to secure platform hardware components. In various embodiments, consistent state may be achieved, at least in part, by computing secure tag information and storing the secure tag information in a secure and/or otherwise protected device register. Consistent with embodiments disclosed herein, the tag information may be used to derive keys used to encrypt and/or decrypt stored state information. Tag information may further be used in connection with verification operations prior to using the information to derive associated keys.
Claims19
A method for managing a protected software function performed by a computing system comprising secure hardware, a processor, and a non-transitory computer-readable medium storing instructions that, when executed by the processor, cause the computing system to perform the method, the method comprising:
- receiving at least one protected input from the secure hardware and encrypted initial program state information;
- retrieving a previous secure tag and a current secure tag associated with the encrypted initial program state information from a protected memory register of the secure hardware;
- decrypting the at least one protected input using a program input decryption key to generate decrypted program input and a nonce value;
- comparing the nonce value and the previous secure tag to determine that the nonce value and the previous secure tag match;
- generating a state decryption key based on a protected fixed key and the previous secure tag;
- decrypting the encrypted initial program state information using the state decryption key to generate decrypted initial program state information;
- executing the protected software function using, at least in part, the decrypted program input and the decrypted initial program state information to generate updated program state information and program output information;
- generating a state encryption key based on the protected fixed key and the current secure tag;
- encrypting the updated program state information using the state encryption key to generate encrypted updated program state information;
- and
- storing the encrypted updated program state information in system memory maintained on the non-transitory computer-readable medium.
Dependencies are inferred from the claim text.