With respect to other physiological signals, PPG data present some advantages since they can be captured using widely diffused, comfortable, and low-cost sensors.In this paper, we present a feasibility study on continuous authentication techniques based on PPG signals. A biometric recognition method based on a correlation approach is first presented. Then, the accuracy of this method is evaluated on different datasets describing signals of variable time duration. Finally, the performance of continuous enrollment strategies are investigated.The obtained results suggest that PPG signals present sufficient discriminability to be used in biometric applications that do not require very high accuracy. Moreover, the use of continuous enrollment strategies can improve the performance of continuous authentication systems.