An illustrative method for transferring data to a device includes identifying the data that is to be transferred to the device, modulating the data with a signal, providing the signal to a contact microphone that is in physical contact with an individual, and transmitting the signal through a body of the individual to the device using the contact microphone. An illustrative method for authenticating the individual includes transmitting a signal through a body of the individual in response to the individual physically contacting an authentication device, receiving a modified signal including the signal as modified by the body of the individual, removing the signal from the modified signal to identify a unique body signature of the individual, comparing the unique body signature to a database to determine if the database includes the unique body signature, and selectively authenticating the individual based upon whether the database includes the unique body signature.