US 8,914,648 B1Granted

Stateless and stateful implementations of faithful execution

AssigneeSandia Corporation

InventorsLyndon G. Pierson, Edward L. Witzke, Thomas D. Tarman, Perry J. Robertson, John M. Eldridge, Philip L. Campbell

Life of this patent

Estimating the term…

patentgrep

Loading patent…

Abstract

A faithful execution system includes system memory, a target processor, and protection engine. The system memory stores a ciphertext including value fields and integrity fields. The value fields each include an encrypted executable instruction and the integrity fields each include an encrypted integrity value for determining whether a corresponding one of the value fields has been modified. The target processor executes plaintext instructions decoded from the ciphertext while the protection engine is coupled between the system memory and the target processor. The protection engine includes logic to retrieve the ciphertext from the system memory, decrypt the value fields into the plaintext instructions, perform an integrity check based on the integrity fields to determine whether any of the corresponding value fields have been modified, and provide the plaintext instructions to the target processor for execution.

Claims23

Dependent claims

A processing system, comprising:

system memory to store a ciphertext including value fields each including an encrypted executable instruction and integrity fields each including an integrity value for determining whether a corresponding one of the value fields has been modified, wherein the value fields are distinct from the integrity fields;
a target processor to execute plaintext instructions decoded from the ciphertext;
and
a protection engine coupled between the system memory and the target processor, the protection engine including logic to:
retrieve the ciphertext from the system memory;
decrypt the value fields into the plaintext instructions, wherein the ciphertext is encrypted using a stateless encryption scheme and wherein the logic to decrypt the value fields into the plaintext instructions includes logic to generate a plaintext instruction v for each of the value fields by applying one of the following decryption functions to the value fields:
v=d(VF)⊕a,
v=d(VF)⊕g(a), or
v=b(d(VF)⊕g(a)),
where v represents the plaintext instruction, d and b represents invertible decryption functions, g represents a noninvertible encryption function, VF represents encrypted contents of a value field, a represents an address in the system memory, and ⊕ represents an XOR or XNOR operator;
perform an integrity check based on the integrity fields to determine whether any of the corresponding value fields have been modified;
and
provide the plaintext instructions to the target processor for execution.

10 more elements

A non-transitory computer-readable storage medium that provides instructions that, if executed by a computer, will cause the computer to convert an unencrypted software program including plaintext instructions into a ciphertext by performing operations comprising:

encrypting the plaintext instructions into encrypted instructions using an encryption scheme;
inserting each of the encrypted instructions into a corresponding value field of the ciphertext;
generating an integrity value for each of the value fields, the integrity value being an encrypted value different than its corresponding one of the encrypted instructions for determining whether its corresponding one of the encrypted instructions has been modified;
inserting each of the integrity values into a corresponding integrity field of the ciphertext, wherein the value field is distinct from the integrity field;
and
generating a field mapping field of the ciphertext and inserting field mapping data into the field mapping field for associating a given value field to a given integrity field to guide a decryption engine while decrypting the ciphertext.

3 more elements

A method implemented by a trusted volume including a protection engine coupled between a target processor and a memory unit, the method comprising:

retrieving a ciphertext from the memory unit into the protection engine, the ciphertext including value fields each including an encrypted executable instruction and integrity fields each including an encrypted integrity value, wherein the value fields are distinct from the integrity fields, the ciphertext further including a field mapping field;
inspecting the field mapping field to determine how the value fields are associated with the integrity fields, wherein each value field has a corresponding integrity field;
decoding the value fields into plaintext instructions;
performing integrity checks based on the integrity fields to determine if any of the value fields have been modified;
providing the plaintext instructions to the target processor;
and
executing the plaintext instructions on the target processor.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/542,072Filed 17 Aug 2009
Granted: 16 Dec 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G06F 21/52
Monitoring users, programs or devices to maintain the integrity of platforms, e.g. of processors, firmware or operating systems: during program…
G06F 21/64
Protecting data: protecting data integrity, e.g. using checksums, certificates or signatures
H04L 9/0656
Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3: pseudorandom key sequence…
H04L 9/32
Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols: including means for…