PPTA: Privacy-Preserving Task Assignment Based on Inner Product Functional Encryption in SAM
Bibliographic record
Abstract
The explosions of mobile communications and the Internet of Things (IoT) have spawned a new distributed computing paradigm—spatial crowdsourcing, in which workers actively participate in spatiotemporal computing tasks for earning commissions, facilitating the development of urban sharing economic services. Furthermore, to reduce users’ storage space and computational overhead, the server assignment model (SAM) is widely used, which means that crowdsourcing platforms collect sensitive information about tasks and workers, e.g., locations and interests, to perform task assignments accurately. However, in the real world, crowdsourcing platforms are not fully trustworthy and may reveal sensitive information about workers and tasks, which can reduce users’ motivation to use crowdsourcing services. Therefore, how to assign tasks efficiently and securely is still an urgent problem to be solved. In this article, we propose a privacy-preserving task assignment scheme (PPTA), in which the crowdsourcing platform efficiently implements the nearest task assignments without revealing sensitive information about tasks and workers. In PPTA, we utilize inner product functional encryption to achieve circular range queries and multikeyword queries. Considering that workers usually prefer to query the nearest tasks for reducing travel costs, we use the grid location intersection to enable the nearest task assignment. In particular, we design a SAM algorithm, which can improve task assignment rates in multitask and multiworker scenarios. In addition, our scheme can implement user accountability and user revocation, which enhances the security and practicality of the scheme. Finally, we demonstrate the privacy preservation through security theoretical proofs and show the efficiency by constructing extensive comparative experiments, which respectively illustrate the security and the effectiveness of our scheme.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.005 |
| Open science | 0.002 | 0.004 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".