Many everyday activities involve the exchange of confidential information through the use of a smartphone in mobility, i.e., sending on e-mail, checking bank account, buying on-line, accessing cloud platforms, and health monitoring. This demonstrates how security issues related to these operations are a major challenge in our society and in particular in the cyber-security domain. This paper focuses on the use of the smartphone intrinsic and physical characteristics as a mean to build a smartphone fingerprint to enable devices identification. The basic idea proposed in this paper is to investigate how to generate a specific fingerprint that allows to distinctively and reliably characterize each smartphone. In particular, the accelerometer, the gyroscope, the magnetometer, and the audio system (microphone-speaker) are taken into account to build up a composite fingerprint based on a set of their distinctive features. Many experiments have been carried out by analyzing different classification methods, diverse features combination configurations, and operative scenarios. Satisfactory results have been obtained showing that the combination of such sensors improves smartphone distinctiveness.