Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Adversarial CAPTCHAs   Following the principle of to set one's own spear against one's own shield,
we study how to design adversarial CAPTCHAs in this paper. We first identify
the similarity and difference between adversarial CAPTCHA generation and
existing hot adversarial example (image) generation research. Then, we propose
a framework for text-based and image-based adversarial CAPTCHA generation on
top of state-of-the-art adversarial image generation techniques. Finally, we
design and implement an adversarial CAPTCHA generation and evaluation system,
named aCAPTCHA, which integrates 10 image preprocessing techniques, 9 CAPTCHA
attacks, 4 baseline adversarial CAPTCHA generation methods, and 8 new
adversarial CAPTCHA generation methods. To examine the performance of aCAPTCHA,
extensive security and usability evaluations are conducted. The results
demonstrate that the generated adversarial CAPTCHAs can significantly improve
the security of normal CAPTCHAs while maintaining similar usability. To
facilitate the CAPTCHA security research, we also open source the aCAPTCHA
system, including the source code, trained models, datasets, and the usability
evaluation interfaces.

31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio