Since DVI does not support High-bandwidth Digital Content Protection (HDCP) encryption by default, by using hardware which only includes DVI ports, the video protection is not guaranteed. This is the biggest drawback of DVI.
Since HDCP protects video from illegal copying, this feature is very critical for video surveillance systems. DVI has several variants: DVI-D (digital only), DVI-A (analog only) and integrated DVI-I which carries both digital and analog video.