A survey on Image steganography Techniques Based on capacity and security Suzwanl Bint’ Ismail Faculty of Mathematical and computer science Universiti Teknologi Mara Shah Alam Selangor [email protected]. com Abstract ” Steganography Is an art of hiding communication by embedding secret messages into cover media so that people cant detect the existence of the secret message. It is an invisible communication that hides data such as image, text, audio, video and many more. For Image steganography, the secret message Is Inserted Into the image files.
Stego-key can be used to hide the data and the resultant image is alled as a stegc-image. This technique is efficient and it is vital for the internet users who sharing their secret data since the number of attackers have Increased day by day. In this paper, we explain about steganography metrics. We also explain three techniques of steganography which are LSB, APPM and PVD and highlight their pros and cons In terms of security and capacity so that other users can determine which technique is suitable to be used.
Keywords: steganography, Image steganography, steganography metrics, LSB, APPM, PVD l. INTRODUCTION With the recent advances in computing technology and its intrusion In our daily life, he need for private and personal communication has increased. Most of us used Insecure pathways tor sharing and sending essential and secret Information. In order to prevent this from happen, cryptography and steganography can be used. According to , cryptography Is a process by which the secret information is distorted such that only the intended recipient can understand it.
In cryptography, the original secret information is called as plaintext, and the encrypted secret information Is called as cipher text. The secret Information can be in text, Image, audio, video and many more. The second method Is steganography. Steganography Is different from cryptography. [21 stated that steganography Is an art of hiding secret communication by embedding secret information into cover media. It is a technique to hide the secret information so that It cant be seen by naked eyes. It allows users to embed large amount of information within cover media such as image, audio, video and many more.
The secret information can be in plaintext, cipher text or anything that can be represented as a bit stream .  stated that, in image steganography the secret file Is inserted into cover image ana proaucea a stego Image. tego Image Is tnen transmlttea to tne reclplent through covert channel. It allows users to embed a large amount of information within cover media such as text, image audio, video and many more. The recipient is able to extract the secret message using retrieving process and secret keys that are provided by sender. A model of steganographic process with cryptography is illustrated in Fig. . Fig. 1: A model of the steganographic process with cryptography In this paper, we will compare three steganography techniques in terms of security and capacity. The rest of paper is organized as follow. Section II describes the related orks about LSB, APPM and PVD methods. Section Ill describes about steganography metrics. Comparison between three types of steganography methods is described in section IV. Conclusion is given in section V. II. RELATED WORKS Nowadays security has become one of the most critical problems for information technology.
Many users want to use their information in a secure manner. Cryptography and steganography can solve this issue. Several techniques of steganography such as Least Significant Bit (LSB), Transform Domain techniques, Statistical methods and also Distortion techniques have been explained in . They lso proposed a new scheme that uses Rivest, Shamir, Adleman (RSA) algorithm and Diffe Hellman algorithm to encrypt the data. For steganography, they used LSB method which replaces the least significant bit of pixel value with the encrypted information bits.
In , Rosaline, S. 1. , & RengaraJaswamy, C. used Stream Cipher and also adaptive pixel pair matching (APPM) to produce a stego image. In , Gadiparthi, Sagar, Sahukari, & Chowdary proposed a new method that comes from a combination of LSB and PVD Modulus Methods. They used LSB method for smooth areas whereas PVD modulus method for edge area pixel pairs. The combination of both methods produced stego image with acceptable quality and more secret information can be embedded. In , they proposed three steganographic approach based on LSB technique.
In , they reviewed several steganalytic techniques used to attack the PVD method. They also reviewed several methods in order to enhance the level of security of PVD methods against those attacks. APPM and Chaotic Maps have been used in  in order to create a secured and highly efficient steganography technique. [1 1] also used APPM embedding method combined with Nymble System o produce a secured communication. Ill. STEGANOGRAPHY PERFORMANCE METRICS I nere are several Important cnaracters need to De conslaerea wnen stuaylng steganographic systems, which are capacity, robustness and security.
It provides a balance of the desired characteristics associated with a steganographic method.  stated that in order to improve one element, one or both of the other two elements need to be sacrificed. For example, in order to improve security, we need to sacrifice capacity. The relationship between these three characteristics can be expressed in Fig. 2. Fig. 2: Steganographic triangle A. CAPACITY According to , capacity refers to the maximum value of secret bits which could be inserted into cover image, and its presence can’t be detected by intruders. Capacity of steganography has its own constraints.
The first constraint is stego object needs to be undetectable, and the second constraint is that, the properties of stego object should be preserved. B. ROBUSTNESS  stated that, robustness refers to an embedded message’s ability to survive either deliberate attack by attackers or unauthorized users or the random corruption of noise during some phase of the sending process. If secret information is able to survive, then the steganographic technique is said to be very robust. C. SECURITY Security is the ability of a stego object to remain undetectable . The closer the stego image to the cover image, the higher the security.
The security of one stego object can be measured using PSNR. ‘V. COMPARISON BETWEEN LSB, APPM, PVD In this section, we are going to describe and compare LSB, APPM and PVD technique. The comparison is in terms of security and capacity. A. LSB According to [1 2], LSB is a common and simplest technique in steganography to embed secret data in cover media. In this method, least significant bits of cover image are used to be replaced with the bits of secret data. Overview of One Bit LSB method is shown below [1 3]: The letter ‘C’ is an ASCII code 67 (decimal), which is 10000011 in binary.
It needs three consecutive pixels for a 72-bit image to store a C: I ne pixels 10000000 10110101 11100111 DeTore tne LSB Insertlon are: 10100100 101 10111 10110011 001 10011 Then their values after the insertion of a C will be: 10000001 10100100 101 10100 101 10011 00110011 For every technique, there must have advantages and disadvantages. in terms of ecurity, LSB is less secure because it is easily recovered by unauthorized users . Even though it provides an easy way to insert secret messages in images, the data can be extracted easily.
It can occur if the intruders know the secret key and easily extract the secret messages. In terms of capacity, [1 3] stated that a large size of secret messages can’t be inserted into a carrier image by using this LSB method, and it seems impossible to embed a huge amount of messages. LSB technique is considered as the best technique to be implemented with less noise, but it is applicable for a small capacity of payload only. B. APPM APPM is a type of PPM, and they have a difference in the extraction function utilizes . This method can be implemented by choosing a pixel (x,y) in carrier image using random sequence.
Then new coordinate (x’,V) will be calculated by using APPM algorithm. The new coordinate (x’,V) will replace coordinate (x,y), and the procedure will be repeated until all the secret message are embedded . APPM is an embedding method used to minimize the effect of embedding secret data by providing a modest extraction process and a more compact neighbourhood set. This method can increase the embedding efficiency because it can embed more ecret data per modification; hence provide a higher payload without being detectable . According to , security is not applied in this method.
Even though security is not applied, it is also not an easy target for intruders, especially when the hidden secret message is small. C. PVD The PVD method was originally proposed to hide secret data into 256 gray-valued images. Thus, it is hardly to be detectable by naked eyes. PVD is implemented by using the difference of each pair of cover image pixels, in order to determine the amount of message bits that can be inserted . The larger the difference, the more he bits that can be embedded into that pixel pair. Accor01ng to J PVD metnoa produces nlgn quality stego Images compared to otner steganography methods.
It also has its own significant drawback, where the size of payload can be in a small amount only. The size of payload is extremely small compared to other methods like LSB, etc. It is due to the division of the pixel blocks into smooth blocks, where the difference of pixel value is low. V. CONCLUSION In this paper, we discussed about steganography performance metrics that consists of three criteria, which are robustness, capacity and security. We also briefly described and compared three steganography techniques which are LSB, APPM and PVD. We compared these techniques in terms of security and capacity.
For LSB, it is less secure and the capacity of payload that can be embedded are small. For APPM, security is not applied and it can embed a large amount of secret messages in the carrier image. The last one is PVD technique. The capacity of payload that can be embedded using this technique is low, and it can increase its security level. Since it can produce a high quality of stego image, its security level is considered as higher ompared to LSB and APPM. In conclusion, in terms of capacity, APPM is the best technique to be implemented since it can hide the highest amount of payload compared to LSB and PVD.
Stakeholder and Genre Analysis
I am writing a research project. My topic is (how road signs, maps, health apps, and running clubs help and motivate people to run). In This paper I need to identify and analyze the possible stakeholders, then analyze the genres. The possible stakeholders like, companies, athletes, and society, etc.. .The genres that I am planning to analyze are road signs, maps, health apps, and running clubs.
How to write this paper:
Part One: Stakeholder Analysis: Write a 2-page minimum analysis that outlines all of the possible stakeholders for your project and then conduct a more focused analysis of your discourse communities you are considering for your project. Who are these people? Why are they stakeholders? What can they do in response to your findings/proposals/concerns?
Part Two: Genre Analysis: Write a 2-page minimum analysis in which you do two things:
1. Identify the genre sets used by the groups you have identified in part one. What do these groupsread and write on a regular basis? Where do they get their information? What information do they find convincing when making decisions?
2. Determine which genre would be most suitable for you to use when communicating your research to these groups and explain why. Then, analyze these genre sets: what do they look like? How are they organized? What information do they include? How are the sources cited?
3. Close with an answer. You may need to conduct interviews and collect samples of unfamiliar texts in order to complete the analysis. By the end of the stakeholder and genre analysis, you should have determined your audience and your genre, considered how to reach them, and know how to write the text you need to write in order to reach them.
Audience: You are writing this for yourself and for me. This is a process of determining how you will present your findings and what significance they have for your message.
Evaluation: The primary ability you need to demonstrate is analysis. Can you and have you carefully analyzed the potential stakeholder and genres, and then completed a careful textual analysis of your stakeholders and genres? Are your findings supported with evidence? There are many parts to this analysis, so figuring out to organize (suggestion: use subheadings) the text will also be central to the text—and don’t forget to cite any sources you use in your text, including those interviews.
Formatting note: Your paper should be one document, split into two parts. It’s best to use subheadings or new titles because it creates an organized, cohesive text. You do not need a works cited page or bibliography for this project as it is discourse community-focused and not focused on sources.