SLIDE 1 A Simple Generic Attack
Haichang Gao (Xidian University), Jeff Yan (Lancaster University), Fang Cao, Zhengya Zhang, Lei Lei, Mengyun Tang, Ping Zhang, Xin Zhou, Xuqin Wang and Jiawei Li (Xidian University)
SLIDE 2
Introduction
CAPTCHA:
Completely Automated Public Turing Test to Tell Computers and Humans Apart .
SLIDE 3
Gabor Filters
Dennis Gabor laid their theoretical foundations in 1946. The temporal (1-D) Gabor filters The Spatial (2-D) Gabor filters Log-Gabor filters 2D Log-Gabor filters
SLIDE 4
Real World Popular Captchas
SLIDE 5
Our Attack
SLIDE 6
Our Attack : Extracting Components
SLIDE 7
Our Attack : Extracting Components
SLIDE 8
Our Attack : Partition and Recognition
Step 1. Component sorting
SLIDE 9
Our Attack : Partition and Recognition
Step 2. Graph building
SLIDE 10
Our Attack : Partition and Recognition
Step 2. Graph building
SLIDE 11
Our Attack : Partition and Recognition
Step 3. Graph pruning
SLIDE 12
Our Attack : Partition and Recognition
Step 3. Graph pruning
SLIDE 13
Our Attack : Partition and Recognition
Step 4. Recognizing component combinations
SLIDE 14
Our Attack : Partition and Recognition
Step 4. Recognizing component combinations
SLIDE 15
Our Attack : Partition and Recognition
Step 5. Graph search
SLIDE 16
Evaluation : Attack Results
SLIDE 17
Evaluation : Further Applicability Test
SLIDE 18
Evaluation : A Comparison with Prior Art
pixel counting, histogram analysis, CFS Decaptcha: preprocessing, segmentation, post-segmentation, recognition, and post-preprocessing CCS’13: The Robustness of Hollow Captchas. WOOT’ 14:The End is Nigh: Generic Solving of Text-based Captchas.
SLIDE 19
Design Choices : Graph Search Algorithms
SLIDE 20
Design Choices : Extraction Orientations
SLIDE 21
Design Choices : Extraction Orientations
SLIDE 22
Design Choices : Extracting Methods
SLIDE 23
Design Choices : Classifiers
SLIDE 24
Defence
SLIDE 25
Summary and Conclusion
SLIDE 26
Thank you !
