COUNTERACTING RANDOM GUESS ATTACKS AGAINST HUMAN INTERACTIVE PROOFS WITH TOKEN BUCKETS

• US 20090076965A1
• Filed: 09/17/2007
• Published: 03/19/2009
• Est. Priority Date: 09/17/2007
• Status: Abandoned Application

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Elson, Jeremy Eric, Douceur, John R., Howell, Jonathan Ryan
• Application Number:
  US11/856,367
• Publication Number:
  US 20090076965A1
• Time in Patent Office: Days
• US Class Current: 705/55
• CPC Class Codes: G06F 21/36 by graphic or iconic representation
• CPC Class Codes: G06F 2221/2133 Verifying human interaction, e.g., Captcha
• CPC Class Codes: H04L 63/1441 Countermeasures against malicious traffic countermeasures against attacks on cryptographic mechanisms H04L9/002
• CPC Class Codes: H04L 63/1491 using deception as countermeasure, e.g. honeypots, honeynets, decoys or entrapment

Abstract

A system and method that facilitates and effectuates distinguishing a human from a non-human user. A human interactive proof (HIP) employs a token bucket algorithm in order to reduce the success rate for a non-human user employing a guessing or artificial intelligence to solve a substantial number of HIP challenges. The algorithm can employ token buckets associated with IP address and user session from which the user is attempting to solve the HIP challenge. If a token bucket is empty the algorithm can treat a correct response as incorrect and refill a portion of the buckets for a further attempt. This forces two correct responses to be received by a user within the refill quantity for the users bucket(s) before the user is identified as human.

Claims

1. A system for distinguishing between a human and non-human user, comprising:

a human interactive proof (HIP) challenge component that displays a HIP challenge to a user,

HIP determination component that determines if the user is a human or non-human based upon a response to the challenge provided by the user, wherein the HIP determination component employs at least one token bucket associated with the user in making the determination.

2. The system of claim 1, wherein the token bucket is associated with an IP address from which the user is attempting to solve the challenge and the IP address token bucket is initialized to a predetermined initial value.

3. The system of claim 2, wherein a user session token bucket is associated with a user session from which the user is attempting to solve the challenge and the user session token bucket is initialized to a current value of the IP address token bucket.

4. The system of claim 3, wherein the HIP determination component subtracts at least one token from the IP address token bucket upon creation of a user session.

5. The system of claim 4, wherein the HIP determination component subtracts at least one token from the IP address token bucket and subtracts one token from the user session token bucket upon the user submitting a response to the challenge.

6. The system of claim 5, wherein the HIP determination component determines the user is non human if the token bucket is empty.

7. The system of claim 5, wherein the HIP determination component determines that the user is non human or human based upon the response submitted by the user if the token bucket is not empty.

8. The system of claim 7, wherein the HIP determination component refills the IP address token bucket and user session token bucket by a predetermined refill value if the user response is correct.

9. The system of claim 1, wherein the HIP determination component initializes the token bucket to a predetermined initial value.

10. The system of claim 9, wherein the HIP determination component subtracts at least one token from the token bucket upon the user submitting a response to the challenge.

11. The system of claim 10, wherein the HIP determination component determines the user is non human if the token bucket is empty.

12. The system of claim 10, wherein the HIP determination component determines that the user is non human or human based upon the response submitted by the user if the token bucket is not empty.

13. The system of claim 12, wherein the HIP determination component refills the token bucket by a predetermined refill value if the user response is correct.

14. A method for distinguishing between a human and non-human user, comprising:

displaying a HIP challenge to a user; and

determining if the user is a human or non-human based upon a response to the challenge provided by the user, wherein at least one token bucket associated with the user is employed in making the determination.

15. The method of claim 14, further comprising:

associating an IP address token bucket to the user that is associated with an IP address from which the user is attempting to solve the challenge;

initializing the IP address token bucket to a predetermined initial value;

associating a user session token bucket to the user that is associated with a user session from which the user is attempting to solve the challenge; and

initializing the user session token bucket to a current value of the IP address token bucket.

16. The method of claim 15, subtracting at least one token from the IP address token bucket upon creation of a user session.

17. The method of claim 16, subtracting at least one token from the IP address token bucket and subtracting one token from the user session token bucket upon the user submitting a response to the challenge.

18. The method of claim 17, further comprising:

determining that the user is non human if the token bucket is empty; and

determining that the user non human or human based upon the response submitted by the user if the token bucket is not empty.

19. The method of claim 18, refilling the IP address token bucket and user session token bucket by a predetermined refill value if the user response is correct.

20. A system for distinguishing between a human and non-human user, comprising:

means for displaying a HIP challenge to a user; and

means for determining if the user is a human or non-human based upon a response to the challenge provided by the user, wherein at least one token bucket associated with the user is employed in making the determination.