Robust Digital Image Watermarking under Attacks

Abstract

Hiding information in digital data is not new. Different methods of hiding the information are used for different purposes. Steganography hides one form of information into same or other form of information. Intention of steganography is to secretly carry the hidden information. Cryptography usually does not refer to hiding the information exactly but its aim is to protect the contents from malicious attacks/manipulation by scrambling the information contents and making it unreadable unless descrambled. Watermarking also hides the information of one form into information of same or other form. This makes it appear like steganography but the purpose is absolutely different. Here hidden information claims the ownership or authority of host or carrier information. The main purpose however remains same security or protection of information may it be of hidden information or may it be of carrier information. Purpose of watermarking such information and not encrypting it is that decryption of such information can easily expose it. Watermarking helps to conceal the information and hence existence of it remains unnoticed by the attacker or fake claimant. However cryptography can aid watermarking to increase its strength when information to be hidden is first encrypted. newline