An example acoustic detector includes an acoustic transducer, an analog-to-digital converter, an encryption module, and a wireless communication interface. The acoustic transducer is to be coupled to a solid medium and is configured to generate an electrical signal in response to acoustic waves propagating through the solid medium. The analog-to-digital converter is coupled to the acoustic transducer to convert the electrical signal into digital acoustic data. The encryption module is coupled to encrypt the digital acoustic data to generate encrypted acoustic data and the wireless communication interface is coupled to transmit the encrypted acoustic data via one or more radio access technologies (RATs).