Speech watermarking: an approach for the forensic analysis of digital telephonic recordings

In this article, the authors discuss the problem of forensic authentication of digital audio recordings. Although forensic audio has been addressed in several articles, the existing approaches are focused on analog magnetic recordings, which are less prevalent because of the large amount of digital recorders available on the market (optical, solid state, hard disks, etc.). An approach based on digital signal processing that consists of spread spectrum techniques for speech watermarking is presented. This approach presents the advantage that the authentication is based on the signal itself rather than the recording format. Thus, it is valid for usual recording devices in police-controlled telephone intercepts. In addition, our proposal allows for the introduction of relevant information such as the recording date and time and all the relevant data (this is not always possible with classical systems). Our experimental results reveal that the speech watermarking procedure does not interfere in a significant way with the posterior forensic speaker identification.

Speech watermarking: a solution for authentication of forensic audio digital recordings

In this paper we discuss the problem of authentication of forensic audio when using digital recordings. Although forensic audio has been addressed in several papers the existing approaches are focused on analog magnetic recordings, which are becoming old-fashion due to the large amount of digital recorders available on the market (optical, solid-state, hard disks, etc). We present an approach based on digital signal processing that consist of spread spectrum techniques for speech watermarking. This approach presents the advantage that the authentication is based on the signal itself rather than the recording support. Thus, it is valid for whatever recording device. In addition, our proposal permits the introduction of relevant information such as recording date and time and all the relevant data (this is not possible with classical systems). Our experimental results reveal that the speech watermarking procedure does not interfere in a significant way with the posterior forensic speaker identification.