Digital watermarking embeds invisible identifying information into digital content like audio, video, and images. This allows copyright owners to establish ownership and prevents unauthorized distribution even if the content is copied. There are different types of watermarks that can be embedded, including robust watermarks that are difficult to remove and fragile watermarks that are destroyed if the content is tampered with. However, watermarks are not impossible to attack, as image processing techniques can potentially disable or overwrite them.

1. DIGITAL WATERMARKING1

2. INTRODUCTION:- Think of a multimedia data that is being distributed over the Internet. Someone downloads it , claims it that he has the copyright, and sells it. In these kinds of situations, digital watermarking techniques can be used for establishing ownership rights, ensuring authorized access, preventing illegal reapplication and facilitating content authentication.2

3. “Digital watermarking is the process of embedding information into a digital signal in a way that is difficult to remove.” The signal may be audio, pictures or video, for example. If the signal is copied, then the information is also carried in the copy. A signal may carry several different watermarks at the same time.3

4. General Procedure for Digital Watermarking:4

5. WATERMARKING LIEF-CYCLE5

6. ATTACKS:- Attacks on watermark may not necessarily remove the watermark, but disable its readability. Image processing and transforms are commonly employed to create and apply watermarks. These same techniques can also be used to disable or overwrite watermarks. Multiple watermarks can be placed in an image and one cannot determine which one is valid. Currently watermark registration service is "first come, first served." Someone other than the rightful owner may attempt to register a copyright first.6

7. TYPES OF ATTACKS ON WATERMARKSRemoval attacksGeometrical attacksCryptographic attacks Protocol attacks7

8. TYPES OF WATERMARK:(1)ROBUST WATERMARK: A robust watermark is a watermark that is difficult to remove from the object inwhich it is embedded.(2)FRAGILE WATERMARK: A fragile watermark is destroyed if anybody attempts to tamper with the object inwhich it is embedded.(3)VISIBLE WATERMARK: A visible watermark is immediately perceptible and clearly identifies the cover object as copyright-protected material, much like the copyright symbols ã, â, and ä (4)INVISIBLE WATERMARK: An invisible watermark is not normally perceptible, but can still be used by the rightful owner as evidence of data authenticity in a court of law.8

9. Important ParametersTransparency Robustness SecurityCapacityInvertibility (reversibility) Complexity Possibility of verification9

10. Common watermarking techniques Choice of Watermark ObjectTime domain-LSB Modification

11. Frequency Domain

12. Wavelet Domain10

13. APPLICATION Owner identification and proof of ownership11

14. Broadcast monitoring