Data Authentication Using Cryptography

We present a novel approach using cryptography for data authentication. The key idea is to provide a encoded quantized data projection as authentication data. This can be correctly decoded with the help of an authentic data using as side information. Crypt ography source coding provides the desired robustness against legitimate variations while detecting illegitimate modification. Additional adjustments might not change the meaning of the content, but could be misclassified as tampering. Users might also be interested in localizing tampered regions. Distinguishing legitimate encodings with possible adjustments from tampering and localizing tampering are the challenges addressed in this paper. We apply cryptography source coding and statistical methods to solv e the data authentication problem. Experimental results have been presented for data authentication