Abstract: A method including collecting, by a processing device, raw data regarding an input to fill a form field. The method further includes converting, by the processing device, the raw data to test data, wherein the test represents behavioral characteristics of the entry of the input. The method further includes identifying a human characteristic model corresponding to the behavior characteristics of the entry of the input. The method further includes generating a predictor from a comparison of the test data against the corresponding human characteristic model. The predictor includes a score indicating a probability that the input originated from a human user or from a malicious code imitating the human user.