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Security and Communication Networks

Security and Communication Networks / 2017 / Article / Tab 4

Review Article

A Survey on Breaking Technique of Text-Based CAPTCHA

Table 4

Comparisons of typical methods based on nonsegmentation for breaking adherent CAPTCHA.
ExampleSourceSuccess rateReferenceBreaking methodYear
EZ-Gimpy Gimpy92%[20]Shape context matching algorithm2003
33%
EZ-Gimpy99%[57]Correlation algorithm2004
Program generation55%[62]RNN2011
Program generation54.9%[63]2D LSTM-RNN2013
reCAPTCHA99.8%[30]DCNN2013
reCAPTCHA31.75%[64]HMM2015
Note. RNN: recurrent neural network, 2D LSTM: 2-dimensional long short-term memory, DCNN: spatial displacement of the neutral network, HMM: Hidden Markov model.