Cryptography and Steganography. A multilayer Data Security Approach

Textbook , 2021 , 86 Pages , Grade: 2

Computer Science - IT-Security

This book focuses on the implementation of Image steganography and modifying the existing technique to add more security to a normal steganography technique. The Book emphasizes various techniques used in steganography with methodology, algorithm, MAT LAB implementation and implementation in Java.

There is data everywhere, in the form of images, text and audio/video files. Some data is very crucial or personal and needs to be kept confidential. For that reason, we have cryptography. Cryptography is the science of encrypting a message such that an unauthorized party cannot comprehend what that message means. Only those who possess the key can decrypt the message. There might be cases where just encrypting the information is not enough, since an encrypted message can raise suspicion.
Steganography is the science of hiding a message completely inside another form of data so that the existence of the actual message is not revealed during communication. It is possible to hide the image in any of the digital formats whether it is images, videos or even audio files. Images are popular because they are really frequent on the internet and hence do not arouse suspicion.
This book intends to give an overview cryptography with image steganography.

Table of Contents

Chapter 1: Cyber Security

1. Cyber Security

Chapter 2: Cryptography

2. Cryptography
2.1. Process of Cryptography
2.1.1. Traits of Cryptography
2.2. Symmetric key Cryptography
2.3. Public-Key Cryptography
2.4. Hash Functions
2.5. Common Areas of Cryptography

Chapter 3: Steganography

3. Steganography
3.1. Digital Steganography
3.2. Uses of Steganography
3.3. Workflow of Steganography
3.4. Steganography Users
3.5. Steganography Vs. cryptography
3.6. Steganography Use by criminals
3.7. Steganography Detection
3.8. Applications of Steganography
3.8.1. Secret Communication
3.8.2. Copyright protection
3.9. Characteristics of steganography
3.10. Models of steganographic system
3.10.1. Text Steganography
3.10.2. Image Steganography
3.10.3. Audio Steganography
3.10.4. Video Steganography

Chapter 4: Image Steganography

4. Image Steganography
4.1. Architecture of Image Steganography
4.2. Techniques for Image Steganography
4.2.1. Spatial Domain Techniques
4.2.2. Normalized Histogram
4.2.3. Spatial Filtering
4.2.4. Least Significant Bit
4.2.5. The Binary Pattern Complexity (BPC)
4.2.6. Pixel Value Differencing (PVD)
4.2.7. Transform Domain Techniques
4.2.8. Spread Spectrum Techniques
4.2.9. Masking and Filtering Techniques
4.2.10. LSB BASED DATA HIDING METHOD
4.3. Methodology
4.4. Basic Steganography Model
4.5. Algorithm for Steganography
4.6. Pseudocode
4.6.1. ENCODER()
4.6.2. BIT MANIPULATION
4.6.3. DECODER( )
4.6.4. BYTE DATA

Chapter 5: Matlab implementation

5. Matlab implementation
5.1. Matlab Toolbox
5.1.1. Common functions used in MATLAB
5.1.2. Graphical user interface (GUI)

Chapter 6: Implementation of Steganography technique in JAVA

6. Implementation of Steganography technique in JAVA
6.1. Text Hiding using bit plane
6.1.1. Algorithms
6.1.2. Outputs
6.2. Hide Image Using Bit Plane
6.2.1. Algorithm
6.2.2. Outputs
6.3. Extraction of hided Text
6.3.1. Extract Text using Bit Plane
6.3.2. Outputs
6.3.3. Extract Image using Bit Plane
6.3.4. Outputs

7. List of Figures

Preface

There is data everywhere, in the form of images, text and audio/video files. Some data is very crucial or personal and needs to be kept confidential. For that reason, we have cryptography. Cryptography is the science of encrypting a message such that an unauthorized party cannot comprehend what that message means. Only those who possess the key can decrypt the message. There might be cases where just encrypting the information is not enough, since an encrypted message can raise suspicion.

Steganography is the science of hiding a message completely inside another form of data so that the existence of the actual message is not revealed during communication. It is possible to hide the image in any of the digital formats whether it is images, videos or even audio files. Images are popular because they are really frequent on the internet and hence do not arouse suspicion.

This book intends to give an overview cryptography with image steganography. This book focuses on the implementation of Image steganography and modifying the existing technique to add more security to a normal steganography technique. Book emphasizes various techniques used in steganography with methodology, algorithm, MAT LAB implementation and implementation in Java.

Chapter 1: Cyber Security

1. Cyber Security

Cyber security is the method of safeguarding public and private networks, servers and computers from cyber-attacks. Actually, a cyber-attack is an illegal attempt made by hackers to enter into a particular server or computer of an individual or an organization for the benefit of their own. Hacker use malware, phishing and man in the middle attacks to get into the systems. Cyber security prevents individuals or organizations from these types of attacks. There are many methods covered under cyber security two of them are cryptography and steganography. In today’s modern world we are surrounded by a ton of data in many different forms in earlier days the data was stored in physical files and now a days we store our data in physical as well as digital but most of the data is stored in digital form . Now you must be thinking “Why are we shifting from the physical files to digital? The answer is with the help of the modern tech we are able to produce at a much faster rate which in turns is generating a ton of data every day and it is getting impossible to store the data in physical files as big MNC’s have bigger stack of data and every data has some value of some sorts and the bigger the data the more difficult it becomes to manage it in the physical file system . When similar kind of data is processed it transforms into information. Now information is really valuable and we all know that there are people who like to steal valuable stuff, similarly in the age of computers there are people who steals your information by malicious means and use that information for their own advantage.

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Figure 1.1: Cyber Security

Technologies designed to protect data, program, devices from any kind of damage is known as cyber security and this is divided in categories such as application security, information security, network security and information security and operational security.

We are heading towards a techno-savvy world but in this era it is quite obvious that our data fall a prey in hands of malicious people or firms and we land up in trouble.

There are various types of Cyber Threats like:

- Phishing
- Malware
- Ransomware
- Social Engineering

So, there is when Cyber security comes as a savior. Cyber Security is the process of limiting our sensitive information from malicious people using measures like Cryptography (encryption/decryption), Antivirus software, DNS filtering etc.

There are various security mechanisms has been shown in the following diagram.

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Figure 1.2: Cyber Security Mechanisms

Cyber Security is a way of safeguarding electronic devices , networks and the data stored on them from piracy, revelation or swindling. Cyber security targets to lower down the probability of cyberattacks and shields the confidentiality of facts, figures and statistics available online.

Even though we're not aware of it, cybersecurity is becoming a significant part of our daily life in multiple ways. There are parts of cybersecurity at work in everything we do, from banking to browsing on our personal computers. Cybersecurity is a set of methods and processes for safeguarding networks, devices, programmes, and data from cyber threats or unauthorized access. Information technology security is another term for it. As attackers utilize new evolving methods like social engineering, etc. to acquire access to our personal data without our permission, cyber-attacks are becoming extremely advanced and a threat to our data. If we look at the current situation, people are working from home owing to the worldwide pandemic, and as a result, we are now becoming increasingly dependent upon technology. This dependency will continue to grow, and there is no sign that it will slow down.

Social networking sites have made it much easier to engage with one another, but they've also opened new possibilities for cybercrime and information leakage. As a result, it's critical that we learn how to protect ourselves from cyber-attacks by learning how to keep our computers and personal data safe from hackers. Hackers currently use a variety of strategies, including Social Engineering, which is still the simplest type of cyberattack, along with ransomware, phishing, and spyware, etc.

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Figure 1.3: Protected from attackers

The internet is a crucial aspect of communication and information sharing in today's era. The security of information transmitted across an open channel has become a critical concern, involving the usage of confidentiality and data integrity to prevent illegal access and use. The two most popular methods for ensuring security are cryptography and steganography. Cryptography scrambles a message such that it is unreadable and generates impossible to read cypher text. Steganography, on the other hand, is a term that basically means "covered writing." Steganography is the art of concealing data in another medium, such as graphics, in order to achieve secret communication. It does not replace cryptography; rather, its secrecy traits increase security. Cryptography systems are divided into two types: symmetric-key systems, which use a single key that both the sender and the receiver have, and public-key systems, which use two keys: a public key that everyone knows about and a private key that only the message recipient knows about. Cryptography and steganography are frequently linked and have the same goals and services in terms of preserving information's secrecy, integrity, and availability, all of which are critical aspects of computer security. Only the receiver with the secret key may read the hidden message, which could be documents, photos, or other types of data. Cryptography and steganography are means of sending private information and data through open network connection. They're also employed in access control and information confidentiality strategies in computer and network security.

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Figure 1.4: Encryption/ Decryption techniques

For computer users, ensuring data security is a significant task. Corporations, professionals, and home users all have sensitive information they want to keep private. The combination of cryptography with steganography improves communication security and reliability by encrypting the initial message and hiding it in another carrier such as a digital image, video file, etc.

Cyber security is a relatively new field in computing. It is a bit unique in that it formed out of the need of it from other fields. This field mainly deals with the prevention of unauthorized access and theft of data, information, hardware, and software, and is a part of the wider concept of information security. Cyber security has undergone gargantuan changes ever since the advent of the internet, the rise of cloud computing and a more interconnected digital space in general. While the recent advancements in seamless communication have made life a lot easier in many aspects, it has also made it easier to tamper with the channels of communications as well.

As was stated in the introduction, cyber security is a study of foiling the ways of attackers from getting access to computer systems. Weaknesses in the design, operation, implementation or handling of systems lead to openings that a malevolent outsider can exploit and use to gain data or information they shouldn’t be able to have access to. Such occurrences are known as “hacking attacks”, and the person breaching the system is known as a “hacker”. There are several vectors of attack on an unprepared system; one such vector being the “backdoor”. It is an uncommon but unfortunate weakness. What was intentioned to be a secret, developer only method of bypassing the normal process of authentication and verification of identity for utility, a “backdoor”, can instead be used to attack said system. It is generally made for scenarios like when a password is lost, but a clever attacker with access to source code, or intimate knowledge of the OS the system runs, can turn this utility into a easy exploit and take over systems by detecting and using the backdoor through un-intended means. Another vector of attack possible is the Denial of Service (DoS) attack. This is a very common method of attacking specifically online services, in which an attacker will deliberately send an abnormal number of requests, either through one device or multiple devices (then it is known as a Distributed DoS, a DDoS) using a botnet or something similar. All online servers and services are designed to handle a specific number of data requests. This is done to save on unnecessary costs of processing power and storage, as handling data requests simultaneously is expensive. When under a DoS attack, a server can be completely overwhelmed, and end up unable to handle the non-malicious data requests. A recent example of this was the largest-till-date DDoS on Yandex, an image searching engine based in Russia. It had received up to 17 million requests per second at peak, using http pipelining, which allows many http requests to be sent through one TCP connection with no handshake conformation wait time[1]. While the robust systems at Qrator Labs were able to shake of this attack, it would have utterly crippled any server apart from those with such robust systems Google, Qrator, Facebook. Such scenarios are nightmares for any service provider, and many techniques like ip banning, hardware banning, proxy servers are employed to keep the servers functional under such attacks.

Chapter 2: Cryptography

2. Cryptography

Cryptography is a system of securing information by using codes so that only the receiver and the sender have access to it. This prevents unauthorized access to the information. The cryptographic techniques are acquired from mathematical calculations knows as Algorithms. Cryptographic Algorithms are used for various purposes such as digital signatures, data encryption and authentication etc. Cryptography is a study of secure communication techniques which means the communication between two people will be end to end encrypted that means only the sender and receiver will be able to view the message and no one else. The word encryption means concealing the data by converting it into code so it's not readable by anyone else. This feature is used in Passwords as well so that it cannot be hacked. The term cryptography is defined from the greek word ‘Kryptos’ which means hidden. This turns messages into ciphertext which scrabbles the data once it's sent and converts it back once it arrives so this prevents people trying to get information in between the process. In the case of transmitting electronic data, Cryptography is used to encrypt and decrypt text messages. The method used is the secret key system. This makes the third party people to access data more often. Cryptologists created a new method called "public key" system. Every user has two keys one being public and the other one is private. When the message arrives only the receiver’s private key will decode it, meaning scammers will not be able to decode it so this will be much safer than the secret key method.

Cryptography is a method of transforming data through some specific protocols that make it unreadable/usable for a third party that has gotten the data and is trying to use it. The “protocols” is a blanket term for the many types of communication protocols, and these protocols tend to transform data into something completely unintelligible to third parties. In general, modern Cryptography deeply involves advanced mathematics, and these advanced mathematical concepts are used to make encryption/cryptographic algorithms, which depending on the computational hardness, make it nigh impossible for a third party to crack in normal circumstances, though the degree to which is dependent on the use case. One important intrinsic characteristic of good cryptographic algorithms is Kerckhofs’s principle. This is a very important concept in cryptography, and following it will make it so that the algorithms are robust in a manner in which even if the attacker knows exactly how the algorithm works, they will not be able to access the data in a usable form without the given “Key”. The methods in which keys are distribute are generally through analogue means (a USB stick physically given), or other, more complex distribution methods. Examples for such algorithms are TLS, SSL. These specific examples use handshake protocols to verify identities, making them secure. The computational hardness assumption is an important quality of cryptographic algorithms. It is essentially a rough measure of the “one way” computational difficulty; giving a theoretical time for the time it would take for a third party to reverse engineer the transformations performed on the data. When taking into account the rough computational prowess of any third party that would have a vested interest in stealing your data, specific well established algorithms are used for the use case. But while considering the use case, one important thing to consider about the computational hardness assumption is the inclusion of the word “assumption”. There has yet to a mathematically proven method of checking the absolute computational hardness, or the exact amount of time it would take to solve a “problem”, the problem in this case being the cryptographic algorithm. So it is technically impossible to be completely sure about the computational hardness of an algorithm, but it is possible to get usable estimates with reductions. With these methods it is possible to completely tailor what algorithms are used for each use cases.

To secure the information which allows the sender and the intended receiver to see the information. From the word cryptography in which crypt means hidden and graphy means writing. It is based on algorithms which transform messages or images in such a way which makes it difficult to read for an unknown person. Techniques used in this are merging the words in the image, microdots etc. people who are into this field are known as cryptographers.

Cryptography refers to the term in which data is encrypted with the help of mathematical algorithms so that a breacher can only read the data of the message but cannot understand what the message actually is and then the receiver can decrypt the data to read the message. This the most common method used in cryptography and is call the encryption and decryption method. Basically, cryptography means to convert plain text (a text which everyone can read and understand) to a cipher text (a text which can only be read but can’t be understood by the intruding person) and then again converting into the plain text. There are many ways used in cryptography to safeguard the data such as using images with words and using a secret code language for every letter so that only the sender and receiver know what’s in the message. To secure the information which allows the sender and the intended receiver to see the information. From the word cryptography in which crypt means hidden and graphy means writing. It is based on algorithms which transform messages or images in such a way which makes it difficult to read for an unknown person. Techniques used in this are merging the words in the image, microdots etc. people who are into this field are known as cryptographers. Cryptography is a technique to preserve data particulars, information and communications by making use of codes and a set of symbols. The main objective of cryptography is to provide an additional level of security especially at the messages and password level.

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Figure 2.1: Security of the system using Encryption/Decryption

Cryptography provides assured, safe and secured transmission of data in the presence of malicious third parties. Cryptography is a way of using mathematics to encrypt and decrypt data. It gives us data privacy, data integrity and data authentication. By replacing the original data with codes and digital keys, cryptography makes the data unreadable for the hackers. Cryptography has various applications I our day-to-day life like safe and secure web browsing, online banking transactions, system passwords, sim card authentication and encryption and decryptions in apps like e-mails, whatsapp and instagram.

Advanced correspondence has become a fundamental piece of foundation nowadays, a large amount of uses are Web based and it's significant that correspondence be made mystery. Subsequently, the safety of information ignored an open channel has become an important issue and during this way, the classification and knowledge uprightness are needed to make sure against unapproved access and use. This has caused a temperamental development within the field of knowledge stowing away. Cryptography and steganography are the 2 well-known techniques accessible to grant security. One shrouds the presence of the message and also the other misshapes the particular message. Utilizing cryptography, the data is modified into another babble structure and afterward the scrambled information is communicated. In steganography, the knowledge is installed during a picture record and therefore the picture document is communicated. Notwithstanding, within the present PC driven world, cryptography is often connected with scrambling plaintext (conventional message, sometimes alluded to as cleartext) into ciphertext (an interaction called encryption), then, at that time back all over again (known as decoding). Those who practice this field are called cryptographers. Cryptography calculations are separated into symmetric (secret-key) and hilter kilter (public-key) network security conventions. Symmetric calculations are utilized to encode and interpret unique messages (plaintext) by utilizing a similar key. While Asymmetric calculations utilizes public-key cryptosystem to trade key and afterward utilize quicker mystery key calculations to guarantee classification of stream information. In Public-key encryption calculations, there is a couple of keys, one key is known to general society, and is utilized to scramble data to be shipped off the comparing private key collector. The private and public keys are both unique and need for key trade.

2.1. Process of Cryptography

The process of decoding a plain text to a ciphertext is called encryption. A ciphertext appears to be meaningless and is very random but it is the result of encryption on a plain text. Converting a ciphertext back to the plaintext i.e. to its original and easy to read format is called decryption. To do so, a digital key is used to create a ciphertext.

Encryption:

Process in which normal messages are converted to a meaningless message which is done from the sender’s end. The goal is to make as difficult as possible so that nobody can understand what’s written without using a key.

Decryption:

Process of converting the ciphertext back to meaningful text. Takes place at the receiver’s end.

It is used by militaries and government for secret information purposes. It is also used to protect the data, which is being transferred via Bluetooth, networks, telephone etc. For example, Encrypted message: phhw phlq dsc

Decrypted message: Meet me in the garden

2.1.1. Traits of Cryptography

2.1.1.1. Incorruptibility

This protects the information from unauthorized and unintentional modification. It is also called the Integrity of Cryptography.

2.1.1.2. Confidentiality

It is used to protect the information stored in the system providing us with the non-disclosure of data.

2.1.1.3. Authentication

It is used to verify the identity of the data for e.g. of the system or of the user.

2.1.1.4. Non-Repudiation

It assures that the user or the system does not deny the validity of the information. It is legal and is used widely all over. It holds proof from where the data is originated.

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Figure 2.2: Asymmetric Key Cryptography

Cryptography is the technique of changing the secret information to unreadable form. It uses many terminologies as encryption, decryption, cipher text, plain text, etc. [5]. As we used to convert the data in a non-readable form it used to alter the structure of the message. In cryptography the data was protected from an unauthorized person who had no clue about the data but a hacker who might know the algorithms of encryption and decryption might reorganize the data and decrypt it and the information might get leaked.[6]

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Figure 2.3: Cryptography

The latest trends in cryptography concerns with:

Confidentiality – Put the information in such a way that no one can understand.

Integrity – No one can change the information.

Authentication – Confirmation will be shared by both the Sender and receiver.

Non-repudiation – Users who are sending the message cannot deny on the later stages.

Cryptography is mandatory to use specially in the banking organizations like transaction systems, passwords protections, etc.

2.2. Symmetric key Cryptography

In this type of cryptography only a single key that is shared between the sender and receiver. The sender is encrypting the plain text into the cypher text by the key and once receiver receive the encrypted text decrypt by the same key that shared earlier.

2.3. Public-Key Cryptography

In this type of cryptography two types of keys are used public key and private key, public key is used for encrypting and private key is used for decrypting. The public key is announced the public by which they can encrypt, and each individual have its own private key for decrypt.

2.4. Hash Functions

In this technique no key is used. A hash value will be calculated based on the input plain text and the hash value is used for encrypting the passwords and other important information.

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Figure 2.4: Types of Cryptography

2.5. Common Areas of Cryptography

Security systems must provide various guarantees, such as data confidentiality, authentication, data integrity, availability, and non-repudiation. If used properly, cryptography can help provide these guarantees. It can be ensured the confidentiality and integrity of data with the cryptography technique. You can mutually verify the sender and recipient and prevent denial.

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Figure 2.5: Different Services provided by cryptography system

In the world right now the amount of data that is being generated by millions of people and which is being transmitted globally is almost exhausting. Some of the data which is being generated might hold some crucial and personal information that needs to be protected from adversaries. Steganography is one way that this issue can be dealt with.

Chapter 3: Steganography

3. Steganography

Steganography is a mode of concealing secret data into something that is non-secretive and ordinary. The motive of steganography is to hide and swindle. The information is hidden in plain sight. Encrypted messages can be hidden using steganography. In latter-days, steganography is used to hide files within files or images in a device. Steganography tools are categorized into audio, pictures/images or network related tools. Variety of apps have been created such as Xiao, Concealment, Steghide which can be used for performing steganography. Steganography is the art of concealing messages or data in images (for digital steganography). It is somewhat similar to cryptography in use, as a method of making data unreadable, but the method with which it is done is completely different. Instead of transforming data, the data is generally simply hidden in an obfuscated manner in images. While this may not seem that effective at first glance, it is actually very effective when done in practical cases. Media like images, music, videos are very common across the internet, and unless under draconian circumstances, normal media is almost never analyzed with the scrutiny required to detect a standard-level product of steganography. Not only that, but the messages concealed by steganography are impossible for humans to decipher, making it a very cost-effective too in nondescript transfer of data. Steganography might seem confusing when seen from the point of view of cyber security, but it is actually very succinctly useful. Many-a-time you can completely avoid the majority of attacks from third parties by just not giving them any context to data transferred. Let’s take the case that someone needs to share important information that should not be leaked. The first step taken would be to encrypt the data. Then, instead of sending a massive plaintext file filled with garbled text (which points to encrypted data), you can instead send it through images, music or a video by using steganography. This would not draw any attention as images are often not examined for encrypted data. And even if someone does find that the images seem to have suspicious aspects to it (which might point to concealed data), they might not even be able to crack the algorithm used to lace the data into the image, much less the subsequent encryption they will have to face. Using these 2 techniques in conjunction makes a deadly combo that makes information transfer about as safe as possible with conventional methods. Steganography is a technique that is similar to cryptography and is used to hide secret data or files with an non secret data or file. Which means the main data, which is secret, will be designated to the folder of the non-secret data to avoid suspicion. This method can also use encryption as well; this will provide an extra security layer to the data on top of it. The word Steganography is derived from the word ‘steganos’ meaning hidden. The method of Steganography can be used to conceal almost anything and everything. Any text file image, video stream, audio and any other data can be hidden using this method. If the method of encryption is not used with the data then the file is processed in a random way in which the difficulty for theft is high. But most of the times the data is encrypted. Nowadays Steganography is done in the following ways: The data is encrypted then its inserted using a special algorithm that is associated to the path of the other non-secret file. Another way could be that the data could be hidden in the form of pixels in any JPEG image. This method is very distinct compared to the cryptography but both the methods help a lot in preventing scams and securing the data appropriately. Steganography is a technique that is pretty similar to cryptography and is used to hide secret data or files with an non secret data or file.Which means the main data which is secret will be designated to the folder of the non secret data to avoid suspicion.This method can also use encryption as well, this will provide an extra security layer to the data on top of it.

The word Steganography is derived from the word ‘steganos’ meaning hidden. The method of Steganography can be used to conceal almost anything and everything. Any text file image, video stream,audio and any other data can be hidden using this method.If the method of encryption is not used with the data then the file is processed in a random way in which the difficulty for theft is high.But most of the times the data is encrypted. Nowadays Steganography is done in the following ways:The data is encrypted then its inserted using a special algorithm that is associated to the path of the other non secret file. Another way could be that the data could be hidden in the form of pixels in any JPEG image.This method is very distinct compared to the cryptography but both the methods help a lot in preventing scams and securing the data appropriately.

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Figure 3.1: LSB Steganography

Steganography is the method of hiding or covering the secrets in a message which is of no use neither to the sender, receiver and nor to the hacker. This is done to protect the precious data from an intruder. Steganography is more difficult to crack when compared to cryptography. In simple words steganography can be considered as way to hide data. It can use various means such as audio, video or simply an image. Steganography has there been in the world for a really long time.

For an example if a group of people are cutting trees and police want to inform the forest department about it but they were aware that they are under the vision of a hacker, if they will directly tell the forest department about the issue the hacker would inform the people cutting the trees to leave as forest department is coming. So, they sent a random photo of a person in a jungle along with the location where people were cutting trees to the forest department and the next picture they sent was the same photo but without the trees. The forest department understood after looking the second photo that there was something related to trees at the given location. This is the usefulness of steganography in day-to-day life.

This is preferred over cryptography as it is difficult to detect and doesn’t give insight to hacker. It can be confusing for hacker because images can be part of it or promotional and moreover which part/pixel of image, data is encrypted is difficult to judge . Same is with audio it has to be detected using equipment like spectrogram.

Hence these were some brief insights about the buzz term ‘Cybersecurity’ especially Cryptography and Stenography and what importance it holds in today’s digital cum techno savvy world.

Writing something with invisible ink on a paper can be taken up as an example of steganography. Concealing the details of a patient within the X-ray reports without disturbing its film quality with an encryption which can be accessed by the key with the diagnosing doctor. Photographs can be watermarked steganographically as original copy before distributing it so as to distinguish between the initial and the duplicated one.

3.1. Digital Steganography

One of the most widely used receptacle for steganographers is media files such as audios and visuals for e.g. a text document is excessively large which allows to hide a text document with minimal suspicion.

The secret data for example can be hidden inside a picture which has hundreds of pixels which has an elucidated data about its color. The secret data in requires about 2 to 3 bits of pixel. No visible changes are seen as such by the human eye. Special tools are used to extract the hidden information from the encrypted image. Codes are proven to be helpful in extracting the hidden data from the image.

Steganography is the way of covering or masking a particular message within another message. The application of steganography can be fused with encryption with an additional step for hiding or safeguarding data. Steganography can be used to secrete almost any type of data that is texts, audios, videos, images and even networks. It helps to hide fact and statistics from unwanted eyes and unauthorized users.

Different ways have been adopted to hide messages from one another. The types of steganography are –

- TEXT STEGANOGRAPHY – It is the process of hiding texts inside another or by generating a cover message for the original text.
- IMAGE STEGANOGRAPHY – It is a way of deceiving the viewers by embedding a message into an image or by altering a few pixels.
- VIDEO STEGANOGRAPHY – It is the technique of drafting secret messages inside videos which are to the sender and receiver only.
- AUDIO STEGANOGRAPHY – Audio steganography is the method of transmission of data from one end to another by hiding them in audios.
- NETWORK STEGANOGRAPHY – Network steganography is a secret data transmission technique which employs the legal, authorized and permitted traffic as the medium to transfer the hidden data covertly over the doubtful and suspicious network.

[...]

• Grade: 2
• Authors: Jagdish Chandra Patni (Author), Hitesh Kumar Sharma (Author)
• Publication Year: 2021
• Pages: 86
• Catalog Number: V1145619
• ISBN (eBook): 9783346536006
• ISBN (Book): 9783346536013
• Language: English
• Tags: cryptography, steganography, data, security, approach