The robustness of a new CAPTCHA
The robustness of a new CAPTCHA
CAPTCHA is a standard security technology that presents tests to tell computers and humans apart. In this paper, we examine the security of a new CAPTCHA that was deployed until very recently by Megaupload, a leading online storage and delivery website. The security of this scheme relies on a novel segmentation resistance mechanism. However, we show that this CAPTCHA can be segmented using a simple but new automated attack with a success rate of 78%. It takes about 120 ms on average to segment each challenge on a standard desktop computer.
CAPTCHA, Gestalt perception, Robustness, Segmentation attack
36-41
El Ahmad, Ahmad Salah
e6e3d56d-a029-404f-aca6-14a8d54d2f43
Yan, Jeff
a2c03187-3722-46c8-b73b-439eb9d1a10e
Marshall, Lindsay
d8748f0a-584d-465e-b8b9-775fb5b32b32
2010
El Ahmad, Ahmad Salah
e6e3d56d-a029-404f-aca6-14a8d54d2f43
Yan, Jeff
a2c03187-3722-46c8-b73b-439eb9d1a10e
Marshall, Lindsay
d8748f0a-584d-465e-b8b9-775fb5b32b32
El Ahmad, Ahmad Salah, Yan, Jeff and Marshall, Lindsay
(2010)
The robustness of a new CAPTCHA.
In Proceedings of the 3rd European Workshop on System Security, EUROSEC'10.
.
(doi:10.1145/1752046.1752052).
Record type:
Conference or Workshop Item
(Paper)
Abstract
CAPTCHA is a standard security technology that presents tests to tell computers and humans apart. In this paper, we examine the security of a new CAPTCHA that was deployed until very recently by Megaupload, a leading online storage and delivery website. The security of this scheme relies on a novel segmentation resistance mechanism. However, we show that this CAPTCHA can be segmented using a simple but new automated attack with a success rate of 78%. It takes about 120 ms on average to segment each challenge on a standard desktop computer.
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More information
Published date: 2010
Venue - Dates:
3rd European Workshop on System Security, EUROSEC'10, , Paris, France, 2010-04-13 - 2010-04-13
Keywords:
CAPTCHA, Gestalt perception, Robustness, Segmentation attack
Identifiers
Local EPrints ID: 500863
URI: http://eprints.soton.ac.uk/id/eprint/500863
PURE UUID: c7746f5a-a1ab-4c0a-9b72-6d07ae82a227
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Date deposited: 14 May 2025 16:50
Last modified: 14 May 2025 16:51
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Contributors
Author:
Ahmad Salah El Ahmad
Author:
Jeff Yan
Author:
Lindsay Marshall
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