Composite challenge task generation and deployment

1. A method performed by a hardware processor, the method comprising:

receiving at least two challenge test mechanisms of different challenge test modalities, wherein a challenge test mechanism comprises a challenge portion of a challenge-response test for distinguishing between a human operator and a computer;

receiving challenge test operators for combining the at least two challenge test mechanisms;

generating a composite challenge task by combining the at least two challenge test mechanisms using the received challenge test operators;

identifying, using a composite challenge task analyzer, any errors in the composite challenge task by running the composite challenge task;

evaluating, using the composite challenge task analyzer, the composite challenge task to determine (i) a challenge difficulty for the human operator and (ii) a challenge difficulty for the computer; and

implementing the composite challenge task if (i) no errors are identified at the composite challenge task analyzer, (ii) the challenge difficulty for the human operator is below a predetermined threshold, and (iii) the challenge difficulty for the computer is above a predetermined threshold, wherein the implementing the composite challenge task comprises allowing access to a particular network location upon receiving a correct response to the composite challenge task from an accessing entity.

2. The method of claim 1 , wherein evaluating the composite challenge task to determine a challenge difficulty for a computer comprises employing at least one adversarial model to attack the composite challenge task.

3. The method of claim 1 , comprising identifying at least a portion of the composite challenge task that is weak against adversarial attacks.

4. The method of claim 3 , comprising providing a recommendation to a developer of the composite challenge task to correct the at least a portion of the composite challenge task identified as weak.

5. The method of claim 1 , comprising evaluating the composite challenge task during implementation and adapting the composite challenge task based upon attempted attacks by adversaries on the composite challenge task during implementation.

6. The method of claim 1 , wherein the generating a composite challenge task comprises embedding at least one of the at least two challenge test mechanisms into another of the at least two challenge test mechanisms.

7. The method of claim 1 , wherein the identifying any errors comprises performing a syntactic analysis on a program corresponding to the composite challenge tasks by parsing the composite challenge task program.

8. The method of claim 1 , wherein the evaluating the composite challenge task to determine a challenge difficulty for a human operator comprises estimating a length of time that a human operator would spend responding to the composite challenge task.

9. The method of claim 1 , comprising obtaining logs detailing interactions by users with the composite challenge task during implementation of the composite challenge task.

10. The method of claim 9 , wherein the evaluating and determining a length of time that a human operator spends responding to the composite challenge task comprises analyzing the obtained logs.

11. An apparatus, comprising:

at least one hardware processor; and

a computer readable storage medium having computer readable program code embodied therewith and executable by the at least one processor, the computer readable program code comprising:

computer readable program code configured to receive at least two challenge test mechanisms of different challenge test modalities, wherein a challenge test mechanism comprises a challenge portion of a challenge-response test for distinguishing between a human operator and a computer;

computer readable program code configured to receive challenge test operators for combining the at least two challenge test mechanisms;

computer readable program code configured to generate a composite challenge task by combining the at least two challenge test mechanisms using the received challenge test operators;

computer readable program code configured to identify, using a composite challenge task analyzer, any errors in the composite challenge task by running the composite challenge task;

computer readable program code configured to evaluate, using the composite challenge task analyzer, the composite challenge task to determine (i) a challenge difficulty for the human operator and (ii) a challenge difficulty for the computer; and

computer readable program code configured to implement the composite challenge task if (i) no errors are identified at the composite challenge task analyzer, (ii) the challenge difficulty for the human operator is below a predetermined threshold, and (iii) the challenge difficulty for the computer is above a predetermined threshold, wherein the implementing the composite challenge task comprises allowing access to a particular network location upon receiving a correct response to the composite challenge task from an accessing entity.

12. A computer program product, comprising:

a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code executable by a processor and comprising:

computer readable program code configured to receive at least two challenge test mechanisms of different challenge test modalities, wherein a challenge test mechanism comprises a challenge portion of a challenge-response test for distinguishing between a human operator and a computer;

computer readable program code configured to receive challenge test operators for combining the at least two challenge test mechanisms;

computer readable program code configured to generate a composite challenge task by combining the at least two challenge test mechanisms using the received challenge test operators;

computer readable program code configured to identify, using a composite challenge task analyzer, any errors in the composite challenge task by running the composite challenge task;

computer readable program code configured to evaluate, using the composite challenge task analyzer, the composite challenge task to determine (i) a challenge difficulty for the human operator and (ii) a challenge difficulty for the computer; and

computer readable program code configured to implement the composite challenge task if (i) no errors are identified at the composite challenge task analyzer, (ii) the challenge difficulty for the human operator is below a predetermined threshold, and (iii) the challenge difficulty for the computer is above a predetermined threshold, wherein the implementing the composite challenge task comprises allowing access to a particular network location upon receiving a correct response to the composite challenge task from an accessing entity.

13. The computer program product of claim 12 , wherein evaluating the composite challenge task to determine a challenge difficulty for a computer comprises employing at least one adversarial model to attack the composite challenge task.

14. The computer program product of claim 12 , comprising:

identifying at least a portion of the composite challenge task that is weak against adversarial attacks; and

providing a recommendation to a developer of the composite challenge task to correct the at least a portion of the composite challenge task identified as weak.

15. The computer program product of claim 12 , comprising evaluating the composite challenge task during implementation and adapting the composite challenge task based upon attempted attacks by adversaries on the composite challenge task during implementation.

16. The computer program product of claim 12 , wherein the generating a composite challenge task comprises embedding at least one of the at least two challenge test mechanisms into another of the at least two challenge test mechanisms.

17. The computer program product of claim 12 , wherein the identifying any errors comprises performing a syntactic analysis on a program corresponding to the composite challenge tasks by parsing the composite challenge task program.

18. The computer program product of claim 12 , wherein the evaluating the composite challenge task to determine a challenge difficulty for a human operator comprises estimating a length of time that a human operator would spend responding to the composite challenge task.

19. The computer program product of claim 12 , comprising:

obtaining logs detailing interactions by users with the composite challenge task during implementation of the composite challenge task; and

wherein the evaluating and determining a length of time that a human operator spends responding to the composite challenge task comprises analyzing the obtained logs.

20. A method performed by a hardware processor, the method comprising:

creating a combined challenge test for distinguishing between a human user and a computer using (i) at least two challenge test mechanisms of different modalities and (ii) at least one operator identifying how the at least two challenge test mechanisms are to be combined within the combined challenge test;

providing, responsive to running the combined challenge test in a runtime environment, a runtime script identifying errors in execution of the combined challenge test;

testing the combined challenge test, wherein the testing comprises evaluating the combined challenge test to determine (i) a difficulty level for a human operator to respond to the combined challenge test and (ii) an effectiveness of the combined challenge test against a computer adversary; and

implementing the combined challenge test based upon (i) the difficulty level for a human operator being below a predetermined threshold and (ii) the effectiveness of the combined challenge test being above a predetermined threshold wherein the implementing the combined challenge test comprises allowing access to a particular network location upon receiving a correct response to the combined challenge test from an accessing entity.