CAPTCHAs are computer-generated tests that humans can pass but current computer systems cannot. CAPTCHAs provide a method for automatically distinguishing a human from a computer ...
Many financial institutions have deployed CAPTCHAs to protect their services (e.g., e-banking) from automated attacks. In addition to CAPTCHAs for login, CAPTCHAs are also used to...
Shujun Li, S. Amier Haider Shah, M. Asad Usman Kha...
In this paper we explore object recognition in clutter. We test our object recognition techniques on Gimpy and EZGimpy, examples of visual CAPTCHAs. A CAPTCHA ("Completely Au...
We introduce a protocol, that we call Human Key Agreement, that allows pairs of humans to establish a key in a (seemingly hopeless) case where no public-key infrastructure is avail...
HIPs, or Human Interactive Proofs, are challenges meant to be easily solved by humans, while remaining too hard to be economically solved by computers. HIPs are increasingly used ...
Kumar Chellapilla, Kevin Larson, Patrice Y. Simard...