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.