Biometric keystroke signal preprocessing part II: Manipulation

Abstract

Biometric keystroke authentication methods deal with extracting the key-press times to validate the users considering the uniqueness of password entering style. When the proposed algorithms have no sub-system to check the password itself, the keystroke signal should include the key-codes for better discrimination. On the contrary, if the key-codes are already validated, the signal could be irreversibly manipulated to form a new and unique signal. In general, the key-press and inter-key times are directly used as array, subsequent to extraction without any process. Therefore in this paper we propose several techniques for preprocessing the keystroke signal. The main methods we dealt with are binarization, over-quantization and spectrogram conversion. As a result of these conversions, the new signals somehow exhibit same property and tendency of the original signal, while revealing the hidden features.