Automatic video surveillance (AVS) systems are used for continuous and effective monitoring of dangerous and remote sites. Video data acquired by the automatic video surveillance system can be recorded and presented as a proof in front of court law. But digital video data lacks legal validity due to the ease to manipulate them without leaving any trace of modification. Image authentication is the process of giving a legal validity to the video data. By authentication technique content tampering can be detected and we can indicate the true origin of the data. There are two types of authentication schemes, which are
1. Cryptographic data authentication.
2. Watermarking-based authentication.
In this presentation an attempt is made to present the basic features of the image authentication techniques.