@INPROCEEDINGS{HeVirtual,
    author={He, Yan and Zhang, Hanyan and Yang, Edwin and Fang, Song},
    booktitle={2020 IEEE 17th International Conference on Mobile Ad Hoc and Sensor Systems (MASS)},
    title={Virtual Step PIN Pad: Towards Foot-input Authentication Using Geophones},
    year={2020},
    volume={},
    number={},
    pages={649-657},
}