PARAMETER BASED KEY DERIVATION

• US 20130086662A1
• Filed: 09/29/2011
• Published: 04/04/2013
• Est. Priority Date: 09/29/2011
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Roth, Gregory B., Behm, Bradley Jeffery, Crahen, Eric D., Ilac, Cristian M., Fitch, Nathan R., Brandwine, Eric Jason, O'Neill, Kevin Ross
• Granted Patent: US 9,178,701 B2
• Time in Patent Office: Days
• US Class Current: 726/7
• CPC Class Codes: G06F 21/31 User authentication
• CPC Class Codes: G06F 2221/2115 Third party
• CPC Class Codes: H04L 2463/061 applying further key derivation, e.g. deriving traffic keys from a pair-wise master key cryptographic mechanisms or cryptographic arrangements for generation of secret information including derivation or calculation of cryptographic keys or passwords H04L9/0861
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/088 Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms network architectures or network communication protocols for using time-dependent keys in a packet data network H04L63/068
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/50 using hash chains, e.g. blockchains or hash trees

Abstract

Systems and methods for authentication generate keys from secret credentials shared between authenticating parties and authenticators. Generation of the keys may involve utilizing specialized information that, as a result of being used to generate the keys, renders the generated keys usable for a smaller scope of uses than the secret credential. Further, key generation may involve multiple invocations of a function where each of at least a subset of the invocations of the function results in a key that has a smaller scope of permissible use than a key produced from a previous invocation of the function. Generated keys may be used as signing keys to sign messages. One or more actions may be taken depending on whether a message and/or the manner in which the message was submitted complies with restrictions of the a key'"'"'s use.

Claims

1. A computer-implemented method for providing services, comprising:

under the control of one or more computer systems configured with executable instructions,

receiving, from an authenticating party, electronic information encoding a message, a signature for the message, and a set of one or more restrictions on keys derived from a secret credential shared with the authenticating party, the signature being determinable by applying a hash-based message authentication code function to the message, the secret credential, and the set of one or more restrictions, but also being undeterminable having only the hash-based message authentication code function but without having the set of one or more restrictions;

obtaining a key generated at least in part using at least a subset of the set of one or more restrictions;

calculating, by the one or more computer systems, a value of a hash-based message authentication code function by at least inputting into the hash-based message authentication code function;

first input based at least in part on the obtained key; and

second input based at least in part on the set of one or more restrictions;

determining, by the one or more computer systems and based at least in part on the calculated value, whether the signature is valid; and

providing access to one or more computing resources when determined that the signature is valid.

2. The computer-implemented method of claim 1, wherein:

the message comprises a request for access to the one or more computing resources;

the method further comprises determining whether the set of one or more restrictions indicate that the request should be fulfilled; and

providing access to the one or more computing resources is contingent on determining that restrictions indicate that the request should be fulfilled.

3. The computer-implemented method of claim 2, wherein the information encoding the set of one or more restrictions is encoded by a document and wherein determining whether the set of restrictions indicate that the request should be fulfilled includes evaluating the document against a context in which the request was received.

4. The computer-implemented method of claim 1, wherein:

the message comprises a request to access a computing resource of the one or more computing resources;

the information encoding the set of one or more restrictions includes information specifying the computing resource; and

providing access to the one or more computing resources includes providing access to the computing resource when the computing resource matches the specified computing resource.

5. The computer-implemented method of claim 1, wherein:

the information encoding the set of one or more restrictions corresponds to a time period for which the message is valid; and

determining whether the signature is valid is based at least in part on whether the message was submitted during the corresponding time period.

6. The computer-implemented method of claim 1, wherein:

the information encoding the set of one or more restrictions corresponds to a restriction based at least in part on a location; and

determining whether the signature is valid is based at least in part on whether a location of at least one of the one or more computer systems matches the corresponding location.

7. A computer-implemented method for providing services, comprising:

under the control of one or more computer systems configured with executable instructions,

obtaining electronic information encoding (i) a message, (ii) a first signature for the message, and (iii) a set of one or more parameters, the first signature having been generated based at least in part on (i) the message, (ii) a secret credential, and (iii) the set of one or more parameters, the first signature further being undeterminable having only the message and the secret credential but without the set of one or more parameters;

deriving a second credential based at least in part on the secret credential and at least a subset of the set of one or more parameters;

generating, based at least in part on the derived second credential, a second signature;

determining whether the first signature matches the second signature; and

providing access to one or more computing resources when the generated second signature matches the first signature.

8. The computer-implemented method of claim 7, wherein deriving the second credential includes inputting, into a function, the secret credential and the at least a subset of the set of one or more parameters.

9. The computer-implemented method of claim 8, wherein the function is a symmetric message authentication function.

10. The computer-implemented method of claim 9, wherein the symmetric message authentication function is a hash function.

11. The computer-implemented method of claim 9, wherein inputting, into the function, the secret credential and the at least a subset of the one or more parameters is performed as part of Hash-Based Message Authentication Code (HMAC).

12. The computer-implemented method of claim 8, wherein generating the second signature includes inputting to the function both an output of the function and a parameter from the set of one or more parameters.

13. The computer-implemented method of claim 7, wherein the information encoding the one or more parameters comprises an electronic document encoding the set of one or more parameters.

14. The computer-implemented method of claim 8, wherein:

generating the second signature is based at least in part on a key;

the set of one or more parameters include one or more restrictions on use of the key; and

providing access to the one or more computing resources is performed in accordance with the one or more restrictions.

15. The computer-implemented method of claim 14, wherein the key is based at least in part on a result of inputting the secret credential into a function.

16. A non-transitory computer-readable storage medium having stored thereon instructions that, when executed by a computer system, cause the computer system to at least:

obtain an intermediate key that is derived from at least a secret credential and one or more parameters for use of the intermediate key;

apply, based at least in part on the obtained intermediate key, at least a portion of a signature generation process that results in a signature for a message, the signature generation process configured such that the signature is undeterminable, by the signature generation process, to a computing device having the message, the secret credential, and the signature but lacking the one or more restrictions; and

provide the message, the signature, and the one or more parameters to another computer system that is configured to analyze, based at least in part on the one or more parameters and the message, the signature to determine whether the signature is valid.

17. The non-transitory computer-readable storage medium of claim 16, wherein the one or more parameters encode one or more restrictions on use of the intermediate key that are enforced, at least in part, by said another computer system.

18. The non-transitory computer-readable storage medium of claim 16, wherein the one or more restrictions correspond to at least one of a time period within which the intermediate key is usable, a location in which the intermediate key is usable, and one or more services for which the intermediate key is usable to gain access.

19. The non-transitory computer-readable storage medium of claim 16, wherein the instructions, when executed by the computer system, enable the computer system to generate the signature without the computer system having access to the secret credential.

20. The non-transitory computer-readable storage medium of claim 19, wherein, having the set of one or more parameters, the signature is determinable by the signature generation process using either the shared secret credential or the intermediate key.

21. The non-transitory computer-readable storage medium of claim 19, wherein obtaining the intermediate key includes performing an algorithm wherein at least one output of a hash function is input, with at least one of the parameters, into the hash function.

22. A computer system, comprising:

one or more processors; and

memory including instructions that, when executed by one or more processors of a computer system, cause the computer system to at least;

receive one or more electronic communications that collectively encode a message, a signature for the message, and one or more parameters, the signature being generated based at least in part on the secret credential and the one or more parameters;

analyze, based at least in part on the one or more parameters, an intermediate credential derived from at least a portion of the one or more parameters and the secret credential, but without the secret credential, the message and signature to determine whether the signature is valid; and

take one or more actions contingent on determining that the signature is valid.

23. The computer system of claim 22, wherein:

the memory and one or more processors are part of a first server system in a first geographic location;

the computer system comprises a second server system in a second geographic location, the second server system being configured to generate, based at least in part on the secret credential, a different signature;

the first server system and second server system both lack the secret credential;

analyzing the message and signature includes inputting into a function the at least a portion of the one or more parameters and the intermediate credential; and

the first server system and second server system each lack information from which a same signature could be generated, using the function, from the message.

24. The computer system of claim 22, wherein:

the computer system corresponds to a service; and

the one or more actions include providing access to the service.

25. The computer system of claim 24, wherein the one or more parameters limit use of the intermediate credential to use in accessing the service.

26. The computer system of claim 22, wherein:

analyzing the message and signature includes applying a hash function to the intermediate credential;

the one or more parameters include multiple restrictions on use of the intermediate credential; and

wherein the computer system is configured to enforce the restrictions.

27. The computer system of claim 22, wherein:

analyzing the message and signature includes applying a hash function to a key that is derived from the secret credential; and

the instructions, when executed by the one or more processors of the computer system, cause the computer system to further receive the derived key from a key authority computer system

28. The computer system of claim 27, wherein the instructions that cause the computer system to further receive the derived key from the key authority computer system cause the computer system to receive the derived key from the key authority computer system prior to receipt of the message.

29. The computer system of claim 22, wherein the intermediate credential is determined by another computer system different from the computer system.