TY  - RPRT
AU  - El Ahmad, Ahmad S
AU  - Yan, Jeff
AU  - Tayara, Mohamad
A2  - 
T1  - The Robustness of Google CAPTCHAs
PB  - School of Computer Science, Newcastle University, UK
AD  - 
PY  - 2011/05
VL  - 
IS  - 
SP  - 
EP  - 
UR  - http://homepages.cs.ncl.ac.uk/jeff.yan/google.pdf
M3  - 
KW  - captcha
KW  - character
KW  - google
KW  - image
KW  - ocr
KW  - recognition
KW  - segmentation
L1  - 
N1  - 
N1  - 
N1  - 
AB  - We report a novel attack on two CAPTCHAs that have been widely deployed on the Internet, one being Google's home design and the other acquired by Google (i.e. reCAPTCHA). With a minor change, our attack program also works well on the latest ReCAPTCHA version, which uses a new defence mechanism that was unknown to us when we designed our attack. This suggests that our attack works in a fundamental level. Our attack appears to be applicable to a whole family of text CAPTCHAs that build on top of the popular segmentation-resistant mechanism of "crowding character together" for security. Next, we propose a novel framework that guides the application of our well-tested security engineering methodology for evaluating CAPTCHA robustness, and we propose a new general principle for CAPTCHA design. 
ER  -

TY  - JOUR
AU  - Melnik, Sergey
AU  - Gubarev, Andrey
AU  - Long, Jing Jing
AU  - Romer, Geoffrey
AU  - Shivakumar, Shiva
AU  - Tolton, Matt
AU  - Vassilakis, Theo
T1  - Dremel: interactive analysis of web-scale datasets
JO  - Proceedings of the VLDB Endowment
PY  - 2010/10
VL  - 3
IS  - 1-2
SP  - 330
EP  - 339
UR  - http://dl.acm.org/citation.cfm?id=1920841.1920886
M3  - 
KW  - analysis
KW  - dremel
KW  - google
KW  - interactive
KW  - search
KW  - web
L1  - 
SN  - 
N1  - 
N1  - 
AB  - Dremel is a scalable, interactive ad-hoc query system for analysis of read-only nested data. By combining multi-level execution trees and columnar data layout, it is capable of running aggregation queries over trillion-row tables in seconds. The system scales to thousands of CPUs and petabytes of data, and has thousands of users at Google. In this paper, we describe the architecture and implementation of Dremel, and explain how it complements MapReduce-based computing. We present a novel columnar storage representation for nested records and discuss experiments on few-thousand node instances of the system.
ER  -