Abstract: Considering that the existing implicit authentication method for smartphone is difficult to be applied in practice, an implicit authentication mechanism based on context awareness was proposed. Firstly, the tapping behavior data acquired by embedded sensors (i.e. accelerometer, gyroscope, and magnetometer) of the smartphone is used to identify the context information (that is, the user's body posture state). Then, the context feature and tapping feature is extracted from the data after noise elimination which is employed to train the corresponding authentication sub-model for each context. Experiment evaluation is performed using the collected 7000+ data. It is shown that the average false acceptance rate (FAR) and false rejection rate (FRR) of the proposed scheme for different users is 1.29% and 1.03% respectively. Compared with the authentication method without context awareness, FAR and FRR is reduced by 1.72% and 2.59% respectively. The proposed mechanism can effectively improve the accuracy of authentication.

Key words: context awareness, implicit authentication, body posture