Applications of ENF Analysis in Forensic Authentication of Digital Audio and Video Recordings

The electric network frequency (ENF) method is presented as a means of assessing the integrity of digital audio/video evidence. A brief description is given of different ENF types, of phenomena that determine ENF variations, analysis methods, stability within different geographical locations in continental Europe, interlaboratory validation tests, measurement uncertainties, real-case investigations, different effects of compression algorithms on ENF values, and possible problems encountered during forensic examinations. By applying the ENF method in forensic audio/video analysis, one can determine whether and where a digital recording has been edited, establish whether the recording was made at the time claimed, and identify the time and date of the registering operation.