Article directory
1. Basic concept of information hiding
1.1 Concept
Information hiding, also known as data hiding, originated from steganography technology that appeared in ancient times. Unlike cryptography technology, steganography technology makes it difficult for opponents to know the existence of confidential communications or confidential storage by storing confidential data in other public carriers. It is also difficult to find the target to crack, which can achieve more secure confidential communication.
1.2 Basic model of information hiding
1.3 Steps of watermark attack and steganalysis
2. Basic methods of hiding and extracting information
2.1 Basic methods of hiding information
- Information hiding requires embedding and extracting information in a publicly available carrier data,and the embedding cannot alter or significantly alter the contents of the carrier
- Some embedding methods are suitable for a variety of information hiding applications, but some are only used in specific situations.
- Since humans are not sensitive to changes in some components of digital multimedia (digital images, audio, video), an important feature of modern information hiding is that the carrier data is mostly multimedia
- Fourier transform
means that a function that satisfies certain conditions can be expressed as a linear combination of trigonometric functions (sine and/or cosine functions) or their integrals.
- Lower bit replacement and modification LSB-R
- Spread spectrum modulation
is a method of modulating message signals to various frequencies for communication. The information encoding modulation is called a random sequence to form steganographic information.
- Quantization index modulation QIM
- Quantization index modulation QIM is a classic watermarking algorithm proposed by Chen and Wornell of MIT, which can achieve high robustness while having small embedding distortion.
- The main idea of the QIM algorithm is to use a quantizer to quantize the original carrier data into different index intervals based on the watermark information. During watermark detection, the watermark information is identified based on the quantization index interval to which the modulated data belongs.
3. Robust watermark, fragile watermark scheme and related functions
3.1 Robust watermarking
- Concept:
Robust watermarking technology is an information hiding technology mainly for digital content copyright protection. It embeds copyright-related information perceptually and covertly in the original content, mainly including copyright owner or purchaser information, hidden data or experience. The modulated signal is called a digital watermark, and the watermark can be detected later to achieve copyright ownership verification or infringement tracking. - characteristic
3.2 Fragile watermark
- Concept
Fragile watermark technology is a technology that protects the integrity and authenticity of content. It embeds verifiable watermarks into protected digital content in a perceptually covert manner. Authorized parties can determine the authenticity of the content by verifying the watermarks. and integrity. - Purpose
Digital signature, electronic contract - characteristic
4. Steganography schemes and related performance
4.1 Digital Steganography
- Steganography is an important branch of information hiding, which embeds confidential information covertly into publicly available carrier content, and then conceals the fact of confidential communication or confidential storage through the transmission or storage of the carrier.
- Steganography also needs to achieve properties such as perceptual transparency, blindness, and a certain message capacity.
- The steganographic message capacity is generally measured by how many message bits are transmitted per unit size carrier, which is called the embedding rate, and the unit is bits/pixel or bits/non-zero coefficient.
4.2 Digital steganography method
4.3 Steganalysis
The purpose of steganalysis is to determine whether there is hidden information in the carrier, and generally discover the existence of hidden information based on changes in the statistical characteristics of the carrier.
4.4 Steganalysis classification
