Digital Watermarking

Digital watermark is a secretly embedded information in a digital file or media to uniquely identify its source and ownership. It is an advanced implementation of watermarking technique. It is used for different purposes such authenticating media, protecting copyright and tracking the source of data leaks to prosecute the perpetrators. Furthermore, digital watermarks are placed within audio or video files using steganography techniques. However, digital watermarks do not prevent copying of electronic assets; rather it can be employed to detect unauthorized copying of a given digital content and can be further used to enforce copyright and in prosecution procedures.

There are mainly four types of digital watermarking, which are discussed briefly as follows:

• Visible Watermarks: Visible or perceptible digital watermarks are types of watermarks that can be easily seen with a naked eye to imply some sort of ownership such as logos, images, text, etc. placed on digital media that require protection.
• Invisible Watermarks: These types of digital watermarks are embedded in the digital media and employ steganography techniques, i.e. hiding media within another media such image within image. In other words, it cannot be seen by naked eyes and requires special software to process it. It is piece of code covertly embedded into digital media to imply ownership and protect copyright infringements.
• Public Watermarks: Public digital watermarks are types of digital watermarks that can be easily understood and modified by anyone using various software algorithms.
• Fragile Watermarks: Fragile digital watermarks are types of digital watermarks that lose their effectiveness when they undergo some transformations, such as resizing and compression. They are usually employed to detect modification or tampering of digital content.

Digital watermarking techniques are applicable in the following areas:

• Digital forensic investigation
• Copyright protection
• Brand identification
• Video editing
• Authentication systems
• Content management
• More