NDLI: An Audio CAPTCHA to Distinguish Humans from Computers

Content Provider	IEEE Xplore Digital Library
Author	Haichang Gao Honggang Liu Dan Yao Xiyang Liu Aickelin, U.
Copyright Year	2010
Abstract	CAPTCHAs are employed as a security measure to differentiate human users from bots. A new sound-based CAPTCHA is proposed in this paper, which exploits the gaps between human voice and synthetic voice rather than relays on the auditory perception of human. The user is required to read out a given sentence, which is selected randomly from a specified book. The generated audio file will be analyzed automatically to judge whether the user is a human or not. In this paper, the design of the new CAPTCHA, the analysis of the audio files, and the choice of the audio frame window function are described in detail. And also, some experiments are conducted to fix the critical threshold and the coefficients of three indicators to ensure the security. The proposed audio CAPTCHA is proved accessible to users. The user study has shown that the human success rate reaches approximately 97% and the pass rate of attack software using Microsoft SDK 5.1 is only 4%. The experiments also indicated that it could be solved by most human users in less than 14 seconds and the average time is only 7.8 seconds.
Starting Page	265
Ending Page	269
File Size	449301
Page Count	5
File Format	PDF
ISBN	9781424482313
e-ISBN	9781424482313
DOI	10.1109/ISECS.2010.65
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2010-07-29
Publisher Place	China
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	synthetic voice CAPTCHA security natural voice Natural languages Humans Speech recognition Speech Software Security Human voice authentication
Content Type	Text
Resource Type	Article

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