SYSTEMS AND METHODS FOR AUTHENTICATING AND PROTECTING THE INTEGRITY OF DATA STREAMS AND OTHER DATA

• US 20160292458A1
• Filed: 06/21/2016
• Published: 10/06/2016
• Est. Priority Date: 12/14/1999
• Status: Active Grant

• Current Assignee: PLS IV, LLC (Pretium Partners, LLC)
• Original Assignee: Intertrust Technologies Corporation (Fidelio Acquisition Co LLC)
• Inventors: Serret-Avila, Xavier
• Granted Patent: US 10,025,953 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 21/53 by executing in a restricted environment, e.g. sandbox or secure virtual machine
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 2221/2149 Restricted operating environment
• CPC Class Codes: H04L 2209/30 Compression, e.g. Merkle-Damgard construction
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/50 using hash chains, e.g. blockchains or hash trees

Abstract

Systems and methods are disclosed for enabling a recipient of a cryptographically-signed electronic communication to verify the authenticity of the communication on-the-fly using a signed chain of check values, the chain being constructed from the original content of the communication, and each check value in the chain being at least partially dependent on the signed root of the chain and a portion of the communication. Fault tolerance can be provided by including error-check values in the communication that enable a decoding device to maintain the chain'"'"'s security in the face of communication errors. In one embodiment, systems and methods are provided for enabling secure quasi-random access to a content file by constructing a hierarchy of hash values from the file, the hierarchy deriving its security in a manner similar to that used by the above-described chain. The hierarchy culminates with a signed hash that can be used to verify the integrity of other hash values in the hierarchy, and these other hash values can, in turn, be used to efficiently verify the authenticity of arbitrary portions of the content file.

Claims

1. A system for securely evaluating authenticity of software, comprising:

a protected processing environment comprising;

a processor,

non-volatile memory,

volatile memory,

a tamper-resistant barrier, and

a root verification key stored in a manner that is resistant to tampering;

a storage medium storing a data block, said data block at least in part including executable instructions;

a storage location storing a signed root check value and two or more check values, said signed root check value and two or more check values being in a hierarchy of check values, each of said check values having been derived at least in part from a sub-block of said data block or from a plurality of check values in the hierarchy of check values;

input verification logic, said input verification logic protected against tampering, said input verification logic operable to;

authenticate said signed root check value at least in part using said root verification key,

verify the integrity of said two or more check values at least in part using the authenticated root check value or a verified check value in the hierarchy of check values,

verify the integrity of a sub-block of said data block using at least one of said verified check values, and

release said sub-block of said data block for execution based at least in part on the result of said authentication and verification steps; and

one or more storage locations configured to store said authenticated root check value and said two or more verified check values in a manner that is resistant to tampering.

2. The system of claim 1, further including response logic to restrict execution of said sub-block if there is at least one error detected in said authentication or verification steps.

3. The system of claim 2, wherein said verified two or more check values include at least a portion of an nth level of an n-level tree of check values.

4. The system of claim 3, wherein said portion of the nth level of an n-level tree includes all check values in the nth level of the n-level tree.

5. The system of claim 1, wherein said signed root check value is a digital signature of a cryptographic hash value.

6. The system of claim 1, further including logic to determine whether to remove a verified check value from tamper resistant storage.

7. The system of claim 6, wherein the logic to determine whether to remove a verified check value from tamper resistant storage is based at least in part on a determination that all subordinate check values at a next layer of the hierarchy have been verified and are stored in a tamper resistant storage location.

8. The system of claim 6, wherein the logic to determine whether to remove a verified check value from tamper resistant storage is based at least in part on a predetermined total number of stored verified check values.

9. The system of claim 6, wherein the logic to determine whether to remove a verified check value from secure storage is based at least in part on the verified check value'"'"'s level in a tree of hierarchical check values.

10. A method for securely and dynamically authenticating software for execution using a protected processing environment, comprising:

identifying or locating a data block for execution, said data block at least in part including executable instructions;

loading a signed root check value into a tamper resistant processing environment, said signed root check value having been derived from two or more check values, said signed root check value and said two or more check values being in a hierarchy of check values, each check value having been derived at least in part from an uncorrupted sub-block of said data block or other check values in said hierarchy of check values;

authenticating said signed root check value at least in part using a root verification key and input verification logic, said input verification logic and root verification key protected against tampering;

loading a sub-block of said data block into said tamper resistant processing environment;

calculating a first sub-block check value using said input verification logic, said first sub-block check value at least in part derived from said loaded sub-block;

identifying or locating a portion of said hierarchy of check values to be loaded and verified;

loading said portion of said hierarchy of check values into said tamper resistant execution environment;

verifying the integrity of one or more of the loaded check values using said input verification logic, said integrity verification being determined by calculating a hash of one or more of the loaded check values and comparing the calculated hash to either the authenticated root check value or a previously verified check value in the hierarchy of check values;

verifying the integrity of said loaded sub-block using said input verification logic, said integrity being determined by comparing said calculated first sub-block check value to a verified check value from said hierarchy of check values; and

releasing said loaded sub-block for execution at least in part based on the results of said verifying and authentication steps;

wherein said authenticated root check value and said one or more verified check values are stored in a tamper resistant manner.

11. The method of claim 10, wherein said hierarchy of check values comprises an n-level tree.

12. The method of claim 11, wherein and said portion of said hierarchy of check values to be loaded and verified includes all check values in an nth level of an n-level tree.

13. The method of claim 11, wherein the check values at an nth level of the tree includes a check value that comprises a hash of the sub-block of the data block.

14. The method of claim 11, wherein the check values at an nth level of the tree includes a check value derived from a portion of the data block that is larger than the sub-block, said portion including the entirety of the sub-block.

15. The method of claim 14, further including the step of loading one or more additional sub-blocks of the data block into said tamper resistant processing environment prior to calculating said first sub-block check value.

16. The method of claim 10, wherein said authenticated root check values and verified check values are stored in secure memory.

17. The method of claim 11, wherein said portion of said hierarchy of check values to be loaded and verified includes all check values in a first x levels of an n-level tree, where x is less than n, the method further including the steps of:

identifying or locating a second portion of said hierarchy of check values to be verified, said second portion at least including a check value that comprises a hash of the sub-block of the data block;

loading said second portion into said tamper resistant processing environment; and

verifying the integrity of one or more of a loaded second portion of check values using said input verification logic, said integrity verification being determined by calculating a hash of one or more of the loaded check values and comparing the calculated hash to a previously verified check value in the hierarchy of check values.

18. The method of claim 10, wherein said step of identifying or locating a portion of said hierarchy of check values is based at least in part on identifying check values that were at least in part derived from said sub-block.