Digital Watermarking & Encryption & Open-Coded Watermarking

Digital watermarking and encryption are both techniques used to protect digital content, but they serve different purposes and operate in distinct ways. Here's a comparison of the two:

Digital Watermarking

Purpose:

• Protection of Ownership and Integrity: Digital watermarking embeds information into digital content to assert ownership, verify authenticity, or track the distribution of the content. It helps in identifying the source or owner of the content and detecting unauthorized use or alterations.

How It Works:

• Embedding Information: A watermark is embedded into the digital content in a way that is generally imperceptible to users but can be detected or extracted by appropriate tools. This information might include copyright details, the owner's identity, or a unique identifier.
• Robustness: Watermarks are designed to be resilient to common content alterations (e.g., compression, resizing). They can be either visible or invisible, depending on the use case.

Examples:

• Visible Watermarks: A semi-transparent logo or text overlaid on an image.
• Invisible Watermarks: Data encoded within the pixel values or audio signals that is not apparent to the end user but can be detected by specialized software.

Applications:

• Copyright Protection: To assert ownership and discourage piracy.
• Content Tracking: To track how and where digital content is distributed.
• Authentication: To verify the authenticity of content.

Purpose of Spatial and Frequency Domain Techniques in Digital Watermarking

1. Spatial Domain Watermarking:

• Purpose: This technique embeds watermarks directly into the pixel values of an image or the samples of a digital signal. It involves modifying the pixel values or audio samples to include watermark data.
• Application: Typically used for images and audio files where the watermark is integrated into the spatial domain data of the media.

2. Frequency Domain Watermarking:

• Purpose: This technique embeds watermarks by modifying the frequency components of the digital object. It transforms the media into the frequency domain using techniques such as Fourier Transform or Discrete Cosine Transform (DCT), then embeds the watermark data by altering certain frequency coefficients.
• Application: Commonly used for images and video where watermarking is applied to the frequency domain representation to achieve robustness against various types of attacks.

b) Characteristics for Securing Digital Objects with Watermarking Techniques

**1. Robustness:

• Definition: The watermark should remain detectable and intact even after the digital object undergoes various transformations or attacks, such as compression, cropping, or resizing.
• Importance: Ensures that the watermark survives common manipulations and attempts to remove or alter it. This characteristic helps in proving ownership and protecting digital content from unauthorized modifications.

**2. Imperceptibility:

• Definition: The watermark should be embedded in a way that it does not noticeably degrade the quality or usability of the digital object.
• Importance: Maintains the original quality of the digital object while ensuring the watermark is hidden effectively. This characteristic ensures that the watermarking process does not affect the user experience or the visual/audio integrity of the content.

**3. Security:

• Definition: The watermark should be resistant to attempts to detect, remove, or alter it by unauthorized parties. It should include encryption or other techniques to prevent tampering.
• Importance: Ensures that only authorized entities can access or remove the watermark, thereby providing protection against counterfeiting and unauthorized distribution. Security also involves ensuring that the watermarking method is not easily reverse-engineered or exploited.

Summary

• Purpose:

  • Spatial Domain: Embeds watermarks directly into pixel values or audio samples.
  • Frequency Domain: Embeds watermarks by altering frequency coefficients after transforming the digital object into the frequency domain.

• Characteristics:

  1. Robustness: Watermark should survive various transformations and attacks.
  2. Imperceptibility: Watermark should not noticeably degrade the quality of the digital object.
  3. Security: Watermark should be resistant to detection, removal, or alteration by unauthorized parties.

Encryption

Purpose:

• Confidentiality and Security: Encryption transforms digital content into an unreadable format to protect its confidentiality. Only authorized users with the decryption key can revert the content to its original form and access the information.

How It Works:

• Algorithm-Based Transformation: Content is encrypted using algorithms and keys, resulting in ciphertext. Decryption requires the correct key and algorithm to revert the ciphertext back to readable plaintext.
• Key Management: Secure key management is crucial as the encryption and decryption process relies on the secrecy and integrity of the keys used.

Examples:

• Symmetric Encryption: The same key is used for both encryption and decryption (e.g., AES).
• Asymmetric Encryption: Different keys are used for encryption and decryption (e.g., RSA).

Applications:

• Data Protection: To secure sensitive information during storage or transmission.
• Secure Communications: To ensure that messages or data exchanged between parties remain confidential.
• Authentication: To verify the identity of users or systems through encrypted credentials.

Key Differences

1. Objective:

   • Watermarking: Protects ownership, authenticity, and tracks content.
   • Encryption: Secures content from unauthorized access and ensures confidentiality.

2. Visibility:

   • Watermarking: Watermarks can be visible or invisible but are generally designed to be detectable and recoverable.
   • Encryption: The encrypted content is completely unreadable without decryption.

3. Content Alteration:

   • Watermarking: Designed to withstand alterations and still be detectable.
   • Encryption: Ensures the content is not accessible without the key, regardless of any content changes.

4. Usability:

   • Watermarking: Allows the content to remain usable and accessible while providing protection.
   • Encryption: Requires decryption for the content to be usable and readable.

5. Implementation:

   • Watermarking: Embeds information directly into the content.
   • Encryption: Transforms the entire content into an unreadable format.

In summary, digital watermarking is used for asserting ownership and tracking digital content while allowing it to remain accessible. Encryption is used to protect content from unauthorized access by making it unreadable without a decryption key. Each serves a unique role in digital content protection, and they can complement each other in comprehensive security strategies.

The usage of digital watermarking techniques to secure documents.

To secure digital academic certificates and transcripts against forgery and unauthorized alterations, digital watermarking can be an effective technique. Here are two specific uses of digital watermarking to protect these documents:

1. Embedding Invisible Watermarks for Authentication

Usage:

• Purpose: To embed invisible watermarks within the digital academic certificates and transcripts, ensuring that any tampering or unauthorized modifications can be detected.
• Implementation: Use invisible watermarking to insert unique, hidden data into the document's content (e.g., text or images). This watermark is embedded in a way that does not alter the visible appearance of the document but can be detected and extracted by authorized systems.

Benefits:

• Tamper Detection: If the document is altered, the watermark may become corrupted or disappear, alerting the institution to potential tampering.
• Proof of Authenticity: The watermark can contain unique identifiers, such as a cryptographic hash or a digital signature, which can be verified by authorized parties to confirm the document's authenticity.

Example:

• Digital Signature: Embed a digital signature in the invisible watermark that links back to the institution’s secure servers. This signature verifies that the document was issued by the institution and has not been altered.

2. Incorporating Visible Watermarks for Verification

Usage:

• Purpose: To include a visible watermark on the digital academic certificates and transcripts that displays information about the document's authenticity or issuance.
• Implementation: Add a visible watermark, such as a semi-transparent logo, hologram, or a unique code, that is prominently displayed on the document. This watermark should be difficult to replicate or alter without detection.

Benefits:

• Ease of Verification: The visible watermark provides a straightforward method for individuals and institutions to verify the authenticity of the document at a glance.
• Deterrence: A prominent watermark can deter individuals from attempting to forge or alter the document, as it would be obvious if the watermark is not present or is manipulated.

Example:

• Institutional Logo: Place a semi-transparent version of the institution’s logo across the document. This logo could include a unique serial number or QR code that can be scanned to verify the document's authenticity against a central database.

Summary

Invisible Watermarks:

• Purpose: Detect tampering and verify authenticity.
• Method: Embed hidden information that is not visible but can be checked with specialized tools.

Visible Watermarks:

• Purpose: Provide clear and immediate verification of authenticity and deter forgery.
• Method: Display a noticeable element (logo, code) that can be easily recognized and checked.

By employing both invisible and visible watermarking techniques, Bahagian Hal Ehwal Akademik at UiTM can enhance the security and integrity of digital academic certificates and transcripts, making it more difficult for counterfeit documents to be created and used.

Open-Coded Watermarking

a) List TWO (2) Applications of Open-Coded Watermarking

1. Digital Rights Management (DRM):

   • Application: Open-coded watermarking is used in DRM systems to embed copyright information and ownership details into digital content, such as music, movies, and software.
   • Purpose: This helps in tracking and enforcing copyright protections, identifying unauthorized copies, and preventing piracy.

2. Authentication and Verification:

   • Application: Open-coded watermarking is employed to verify the authenticity of digital documents or media files.
   • Purpose: This ensures that the content has not been altered or tampered with. For example, in legal documents or high-value digital images, the watermark can serve as proof of authenticity.

b) Discuss the Open-Code Technique in Digital Watermarking

Open-Code Watermarking Technique:

Overview: Open-coded watermarking is a method of embedding information into digital content by modifying its structure in a way that allows for detection and extraction of the watermark. Unlike some other watermarking techniques that use complex transformations or encryption, open-coded watermarking involves straightforward embedding techniques that maintain the watermark's visibility or structure within the content.

How It Works:

1. Watermark Embedding:

   • The watermark data (such as a unique identifier or copyright information) is embedded directly into the digital content using open coding methods. This could involve modifying specific bits or structures in the digital file, such as embedding the watermark in the pixel values of an image or in specific segments of an audio file.
   • Open-Code: The term "open-code" refers to the use of simple, transparent methods for embedding the watermark, making it possible for the watermark to be detected or extracted using straightforward algorithms.

2. Detection and Extraction:

   • The embedded watermark can be detected or extracted using techniques that recognize the patterns or modifications made during embedding. For instance, the watermark could be extracted by analyzing changes in specific bits or by identifying distinctive patterns added to the content.
   • Open Detection: The simplicity of open-coded watermarking means that the detection process does not require complex or hidden algorithms. It involves analyzing the digital content to find and interpret the embedded watermark.

Advantages:

• Simplicity: Open-coded watermarking techniques are relatively simple to implement and understand, making them accessible for various applications.
• Transparency: The watermarking process can be designed to minimize perceptible changes to the original content, maintaining its quality while embedding the watermark.
• Compatibility: Open-coded watermarks are often compatible with a wide range of digital formats and applications.

Disadvantages:

• Vulnerability: Because open-coded watermarking involves straightforward methods, it may be more susceptible to detection and removal by unauthorized users compared to more complex watermarking techniques.
• Limited Capacity: The amount of information that can be embedded may be limited by the open-coded approach, potentially reducing the effectiveness for some applications requiring more robust watermarking.

Summary: Open-coded watermarking embeds information directly into digital content using simple, transparent methods. It is widely used in applications such as DRM and authentication due to its simplicity and ease of detection, but it may be more vulnerable to tampering compared to more sophisticated techniques.