We study the performance and inuence of various keystroke features on keystroke dynamics authentication systems. In particular, we investigate the performance of keystroke features on a subset of most frequently used English words. Four features including key duration, ight time latency, diagraph time latency, and word total time duration were analyzed using non-parametric Wilcoxon Man-Whitney statistical test technique. Two experiments were performed to measure the performance of each feature individually as well as the results from the combinations of these features. The results of the experiments were evaluated with eight users. The results show that while the combination of hold time and word total duration produces best performance among all four keystroke features combinations, hold time of the key press offers the optimal result if used independently.