Table 3:
Performance statistics of our CAPTCHA attack algorithms.
Precision (%)
Recall (%)
Accuracy (%)
Answered (%)
Wikipedia
72 3
100
67
93
Slashdot
44 4
88
26
53
reCAPTCHA
5 3
100
0.11
25
BotDetect
88 2
96
81
91
Hotmail
68 5
42
50
31