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# Deoxyribonucleic Acid Cryptography Based Least Significant Byte Steganography

Aditya Anavekar(✉) and S. Rajkumar

School of Computer Science and Engineering, Vellore Institute of Technology, Vellore 632014,
Tamil Nadu, India

aditya.anavekar2019@vitstudent.ac.in, rajkumars@vit.ac.in

**Abstract.** Cryptography and steganography are used to safeguard data, but each has its own set of problems. One of the major issues with cryptography is its ridiculous out-put, so the attacker will interrupt the transfer or carefully examine the data from the sender to the receiver. The issue with steganography is that the message is known when the existence of hidden information is revealed or even just suspected. In order to increase information security, an integrated data protection ap-proach employing cryptography and steganography techniques is described in this study. The Least Significant Byte (LSB) Steganography technique and the Deoxyribonucleic acid (DNA) transcription method in cryptography are first suggested. The proposed method is implemented and tested with various performance metrics. Further, experimental results compared with the existing work, and it turns out to be more efficient.

**Keywords:** Cryptography- Steganography · Encryption · Decryption · DNA - Advanced Encryption Standard - Least Significant Byte · IDEA - 3DES

## 1 Introduction

Transferring information includes sensitive data which can be confidential and critical. This information may be captured while it is being transferred over the internet. Nowadays there are a lot of applications on the internet which ask users to fill in their details in forms. Therefore, there is a greater need for technology with which users can communicate or transfer confidential information so that the data is secure and protected. Especially when the user is using an open channel. Data confidentiality and data integrity is the way to prevent attackers and unauthorized users from getting access to information which needs security. Cryptography and steganography are common ways to prevent communication.

The science of cryptography involves utilizing mathematical formulas to encrypt data and transform it into an unreadable form in order to keep messages safe (ciphertext). Therefore, “hidden writing” is the correct definition of cryptography. Explicit text, an encryption algorithm, cipher text, and a key are all components of a cryptosystem. A piece of communication or piece of data that is in plain text is one that is readable and
unencrypted. By utilizing a key, encryption transforms plain text into encrypted text. Using the encryption key in the blank text, the cipher text is encrypted. The process of decrypting involves converting encrypted text back into clear text. The sender and recipient are the only parties with knowledge of the key, which is utilized by information to operate the cryptosystem (cipher system) [13]. Cryptologists can effectively break ciphers by examining the cipher text's substance in order to extract clear text, despite the fact that cryptography is extraordinarily effective at collecting data [8].

On the other hand, steganography is thought of as the art and science of encryption. The local domain and domain modification are the two most used methods for embedding a picture in steganography [7]. Messages are immediately embedded in Lower Bits in accordance with local domain embedding [5].

In this paper, the LSB Steganography technique and the DNA cryptography method are proposed, and it's implemented. The methodology will be followed by analysis against the standard performance metrics. It will also be compared to an existing work similar to this domain.

## 2 Motivation

The motivation behind implementing this method is that DNA cryptography is a conventional cryptic algorithm that can be used to enhance security characteristics. Embedding message encrypted using DNA encryption provides an additional layer of protection and security. Improving the embedding and maintaining the complexity of processing kept us striving to complete this objective.

## 3 Literature Survey

Letters, integers, and special characters that are symmetrically encrypted are the inputs for message encryption using DNA cryptography [1]. It offers one layer of security. The steganography method utilized is DNA Steganography with LSB and Adjacent Base, while the encryption algorithm used is DNA based on the AES algorithm. The encryption key, which has a length of 64 DNA bases (128 bits), is produced at random. The keys used for each encryption are different. Key, length of ambiguity bits, data, and ambiguity bits make up a steganography carrier file (for encoding). The data is triple-layered and secure thanks to DNA steganography. Another author [2] designed the DNA-based Advanced Encryption Standard (AES), which accepts special characters, digits, and letters as input forms. In these methods, the system produced, length 64, 96, or 128 DNA makes up the key. It only offers one security layer, which is seen as being less safe. Another author [3] proposed a method for the encryption of messages using DNA sequences with the letter, number, and special character input forms. The DNA complementary rule, a symmetric encryption algorithm without a key is used for the encryption algorithm and it just offers one layer of security. In another research work [4] DNA-based and steganographic encryption with text files as the input format and DNA-based AES encryption algorithm are presented. Here, LSB and Adjacent base approach of DNA steganography is the technique employed. The key, which has a length of 64 DNA bases (128 bits), is produced at random. The keys used for each encryption are different. The data is triple-layered
secure thanks to DNA steganography, DNA encoding, and DNA-based AES encryption. Text files are accepted as input by the proposed model. DNA is a symmetric encryption method that is based on the DES algorithm. DNA steganography with modified LSB is the steganography technique employed. The numerous methods that are utilized in this model will determine how the 128-bit key is changed. For steganography, the carrier files are cipher text, ambiguity bits, ambiguity length, and total size [9]. LSB steganography is more secure and has four-layer security. This approach improves data embedding and the encryption process. The summary of the various approaches is given in Table 1.

<table><caption>**Table 1.** Comparison study of similar methods.</caption><thead><tr><th>Comparison Criteria</th><th>Algorithm other than DNA encoding</th><th>Steganography method used</th><th>Secret key</th><th>Steganography carrier file</th><th>Security level</th><th>Feedback</th></tr></thead><tbody><tr><td>Message Encryption Using DNA Sequences [3]</td><td>DNA Complementary rule</td><td>No steganography method used</td><td>No key is used for encryption</td><td>-</td><td>Single layer security</td><td>Key less and single protection layer</td></tr><tr><td>An Encryption based on DNA cryptography and Steganography [1]</td><td>DNA based AES algorithm</td><td>DNA steganography with LSB and Adjacent base method</td><td>Key Size: 64 DNA bases i.e., 128 bits Different keys used for each encryption</td><td>File contains the key, data bits, ambiguity bits and its length</td><td>Encoding based on DNA, encrypted using DNA based AES and DNA steganography</td><td>New way to embed in image and DNA encoding</td></tr><tr><td>Hybrid technique for Steganography - based on DNA [14]</td><td>Playfair cipher Encryption</td><td>DNA steganography with LSB method</td><td>Key is given by the user. The key must be only alphabets length &lt; = 25</td><td>Only message and ambiguity bits</td><td>Provides only double layer security to the data</td><td>Steganography is possible but secures with only 2 layers</td></tr><tr><td>Design of DNA based Advanced Encryption Standard (AES) [2]</td><td>DNA-based AES encryption</td><td>No steganography method used</td><td>System generated key, length 64, 96 or 128 DNA</td><td>-</td><td>Single layer security</td><td>Less secure</td></tr><tr><td>The Proposed Model</td><td>DNA based on DES Algorithm</td><td>DNA steganography with modified LSB</td><td>128 bits. But the size will be adjusted based on the algorithm used</td><td>Cipher text, ambiguity bits, ambiguity length, total size</td><td>Four-layer security and more secure LSB steganography</td><td>Enhanced the process of encryption and the way to embed data on the image</td></tr></tbody></table>
# 4 Proposed Method

This section gives a brief description of the overall process of the proposed method and how each module works. Here, DNA encoding technique in Cryptography and LSB steganography method is discussed. It also includes a module called the algorithm selector. The overall flow of the method is shown in Fig. 1.

<figure><img src="image_3.png" /><figcaption>Fig. 1. The workflow of proposed method</figcaption></figure>

In the proposed method, initially the secret message undergoes DNA encoding and the Key is used for selecting the encrypting algorithm. Later, the encoded message is encrypted using the encryption algorithm and the key. Finally, the encrypted bits are embedded on the cover image using LSB steganography and obtain the stego image. The same steps can be reversed to decode back the secret message from the stego image using the key. The method can be used on any type of image. The threshold for message length will depend on the total payload of the image. As only the pixels are modified the method is scalable for any size of image. The proposed method modules are explained briefly in the subsection.

## 4.1 DNA Cryptography

### DNA Encoding

The input data (secret data) is pre-processed before it is encoded. First the text is converted into 8-bit binary form using its ASCII value. These binary bits are then coded into nitrogen bases (A, T, G, C). This encoding is done using the 2-bit conversion which is explained in Table 2.
<table><caption>**Table 2.** Binary to DNA base conversion mapping.</caption><thead><tr><td>Binary</td><td>Nitrogen Base</td></tr></thead><tbody><tr><td>00</td><td>A</td></tr><tr><td>01</td><td>C</td></tr><tr><td>10</td><td>G</td></tr><tr><td>11</td><td>T</td></tr></tbody></table>

The nitrogen bases are split into codon of 3 of 3 bases. These codons are converted to RNA by replacing ‘T’ with ‘U’ and are then converted into its corresponding amino acids using this amino acid table and it is given Table 3. During the conversion of RNA to Amino acids ambiguity bits are separately recorded and stored. The need for ambiguity is due to the factor that there are many amino acids with more than one RNA mapped

<table><caption>**Table 3.** Amino acids and RNA codons mapping</caption><thead><tr><td>Amino Acid</td><td>Codons</td><td>Amino Acid</td><td>Codons</td><td>Amino Acid</td><td>Codons</td><td>Amino Acid</td><td>Codons</td></tr></thead><tbody><tr><td>A</td><td>GCU, GCC, GCA, GCG</td><td>L</td><td>UUA, UUG, CUU</td><td>E</td><td>GAA, GAG</td><td>T</td><td>ACU, ACC, ACA, ACG</td></tr><tr><td>R</td><td>CGA, CGG, AGA, AGG</td><td>K</td><td>AAA, AAG</td><td>G</td><td>GGU, GGC, GGA, GGG</td><td>W</td><td>UGG</td></tr><tr><td>N</td><td>AUU, AAC</td><td>M</td><td>AUG</td><td>H</td><td>CAU, CAC</td><td>Y</td><td>UAU, UAC</td></tr><tr><td>D</td><td>GAU, GAC</td><td>F</td><td>UUU, UUC</td><td>I</td><td>AUU, AUC, AUA</td><td>V</td><td>GUU, GUA</td></tr><tr><td>C</td><td>UGU, UGC</td><td>P</td><td>CCU, CCC, CCA</td><td>B</td><td>UAA, UGA, UAG</td><td>O</td><td>CUA, CUG</td></tr><tr><td>Q</td><td>CAA, CAG</td><td>S</td><td>UCU, UCC, AGU, AGC</td><td>U</td><td>CGU, CGC</td><td>X</td><td>UCA, UCG</td></tr><tr><td>Z</td><td>GUC</td><td>J</td><td>CUC, CCG, GUG</td><td></td><td></td><td></td><td></td></tr></tbody></table>
to it. For each RNA 2-bit ambiguity is noted. For example, '10' is recorded if the 3rd mapped RNA is matched.

The amino acids are then converted back into binary form through 8-binary conversion. The resultant binary data is further sent as the encrypting message to be encrypted.

## 4.2 Encryption

With the key and the algorithm selector the encryption algorithm is decided, and the message is encrypted by the key. In this paper we have included 4 encryption algorithms. The algorithms are Advanced Encryption Standard (AES), Data Encryption Standard (DES), Triple Data Encryption Standard (3DES), and International Data Encryption Algorithm (IDEA).

AES and IDEA encryption uses 128 bits key and follows the standard procedure. DES encryption uses 64 bits key and follows the Electronic Code Book (ECB) mode of encryption. 3DES encryption uses 168 bits key and follows the ciphertext feed-back (CFB) mode of encryption. With variable key lengths the key length is modified based on the algorithm selected. The selected algorithm encrypts the message and outputs in binary form. This binary data is then sent to the LSB embedding module.

DNA Encryption steps involved:

1. Firstly, the secret data (message M) is converted into its ASCII values to an 8-bit binary representation.

2. Using the 2-bit binary to DNA coding converts the binary into DNA bases.

3. Replace the 'T' with 'U' in the nitrogen bases to make it into RNA form.

4. Split the RNA data into codons (where each codon contains 3 DNA bases). Using the amino acid conversion table, these codons are then translated into the relevant amino acid. Keep track of the ambiguity bit during converting.

5. The amino acid and ambiguity are appended as the DNA encoded message.

6. The algorithm selector processes the key, and an encryption algorithm is chosen. The DNA-encoded message is then encrypted using the key.

7. The binary form of the encrypted message is taken and delivered to the embedding process so that it may be added to the cover picture.

The entire process of encryption is graphically represented in Fig. 2.
<figure><img src="image_4.png" /><figcaption>Fig. 2. Encryption Flow Diagram</figcaption></figure>

## 4.3 Algorithm Selection

The algorithm selector is used to decide which encryption algorithm is going to be implemented. The whole process only depends on the key as the key is kept confidential. This makes the encryption more secure as the probability of decrypting the message without the key reduces and increases the time for brute forcing.

First the key is converted into binary from its ASCII value. Then the decimal value of the whole binary value is taken. This decimal value is then put into Eq. 1 and the resultant is used to decide which algorithm to be used.

$$Q = \text{decimal value} \bmod 4 \qquad (1)$$
where $Q = 0,1,2,3$. As in this paper we have included 4 algorithms, each algorithm is given an index number (0,1,2,3). The 'Q' is matched with the index number and the algorithm is selected.

## 4.4 LSB Steganography

LSB steganography technique is one of most common methods of embedding information into the cover image [6]. This method stores data in the least significant bits by replacing LSB bits of the pixel values with the data bits. The LSB bits are selected based on the size of the data to be embedded. There are no requirements for the type of image. Any image with sufficient payload can be used to embed the message. The image used in this method does not need to be processed before its use.

In the proposed model, we deal with RGB channels of the image and embed in all 3 channels. The model which finally receives the embedding bits from the above modules calculates the size and estimates the LSB bits. This process involves the information of the cover image which helps to calculate the available pixels on which embedding can be done. The embedding bits are replaced in the LSB bits of all 3 channels. The embedded data contains 2 different parts of information. The first one is the encrypted bits and the ambiguity bits and the second contains the length of the total data embedded and the length of ambiguity bits. The second part is embedded in fixed pixels. That is the last 32 pixels of the image. Except for these 32 pixels the remaining pixels are available for embedded.

For short messages which have a smaller number of embedding data than the total number of bits in the image the model finds the interval value by which the pixels are skipped. This helps to spread the embedding throughout the image and not only in the initial part of the image in the case of short messages. With no minimum message length, the maximum length will depend on the payload of the image.

## 4.5 DNA Decoding

The decoding process is completely reverse of all the operations done in the encoding part. First the data retrieved from the image is decrypted using the corresponding encryption algorithm which is obtained from the key provided. The decrypted data is in binary and the same steps involved in the encryption are followed in the reverse order.

DNA Decryption steps involved:

1. Retrieve the embedded bits (Cipher text) from the stego image.

2. Select the decrypting algorithm using the key and algorithm selector.

3. Decrypt the cipher text using the algorithm and obtain the binary form of it.

4. Convert the binary to characters using the 8-bit binary ASCII value conversion. This conversion gives us the corresponding amino acids.

5. Map the amino acid with its respective RNA codons (3 DNA bases). This is done using the Ambiguity bits retrieved from the image. The mapped DNA codons are recorded.

6. The DNA is converted back to its binary form using the 2-bit DNA-Binary coding.

7. Finally, the binary data is converted into text using the 8-bit ASCII value con-version.
8. The resultant text is the secret message stored by the sender. These steps will only work only if the key value provided is the same as the key provided by the sender at the time of embedding.

The entire process of decryption is graphically represented in Fig. 3.

<figure><img src="image_5.png" /><figcaption>Fig. 3. Decryption Flow Diagram</figcaption></figure>
# 5 Results and Analysis

The suggested model is implemented using Python, which is then executed in the PyCharm IDE. The experiments are conducted on different images and different sizes of text messages so that we get an overall analysis of the model and its performance.

## 5.1 Dataset

The data set is distinguished into 2 types i.e., the first set contained images and text files to measure the performance of the proposed model. Second, will be a comparison between the same images used in the existing method.

**Data set 1.** For the cover image data set we have taken different types of images which vary in size, type, and color pallets. The images used for analysis are given in Fig. 4.

<figure><img src="image_6.png" /><figcaption>Fig. 4. Image Set (a) Image1 (b) Image2 (c) Image3</figcaption></figure>

And for text file data set which is the message to be embedded into the cover image we have taken three files of different word counts. The character counts and word count of the text files used for analysis are given Table 4.

<table><caption>**Table 4.** Text files set</caption><thead><tr><td>No</td><td>File Name</td><td>Word count</td><td>Character count</td></tr></thead><tbody><tr><td>1</td><td>Message1.txt</td><td>1001</td><td>6909</td></tr><tr><td>2</td><td>Message2.txt</td><td>2001</td><td>13504</td></tr><tr><td>3</td><td>Message3.txt</td><td>3001</td><td>20369</td></tr></tbody></table>

The dataset is chosen in such a way that it checks various types of images and message lengths. The images are chosen selectively as they differ from each other in parameters such as resolution and format. The text messages are randomly generated messages for the given word count. The aim during analysis is to observe the performance of the proposed method for different lengths of messages.
**Data set 2.** For comparison between this model and the existing model, similar images from the existing method [12] are taken. The images used for comparison are given in Fig. 5. Text files are used based on the character lengths.

<figure><img src="image_7.png" /><figcaption>Fig. 5. Comparison Images (a) Lina (b) Peppers (c) Mandrill</figcaption></figure>

## 5.2 Performance Metrics

The performance of the model is measured using the following metrics:

**For encryption/decryption.**

1. Encryption time

2. Decryption time

3. Probability of attack guessing successfully

**For Steganography.**

Table 5 formulate the steganography metrics.

## 5.3 Analysis and Result

**Encryption/Decryption time (in seconds).** The encryption time includes the time taken for DNA encoding and encrypting the message and decryption time includes decrypting the message and DNA decoding. The encryption time ranges from 0.18–0.55 s and decryption time ranges from 0.5–3.1 s. These observations can be seen in Table 6.

**Qualitative Analysis Result.** Table 7 formulates the qualitative analysis of the proposed model.

A decrease in the PSNR value is seen as character count increases. The PSNR ranges from 71.8 dB high to as low as 63 db. This range is greater than the acceptance value (30 dB) and it makes this steganography method rank very good. The higher range of PSNR value corresponds to better quality image with better security. The MSE ranges from 0.0066 to 0.1799. The values are close to 0.0 (zero) which is the ideal value. Similarly, the RMSE is also minimum which does not excide 0.15. The SNR value are > 30 dB which is consider a good value. Less the MSE and RMSE values means there is less difference between the original and embedded image implying lesser differences that can be noticed.

The NCC values are consistent for different text messages and are above 0.5 increasing close to 1 which makes it more robust. The AD gives the average difference
<table><caption>**Table 5.** Steganography metrics</caption><thead><tr><th>Metrics</th><th>Formula</th><th>Parameters</th></tr></thead><tbody><tr><td>Peak signal-to-noise ratio (PSNR) [10]</td><td>PSNR = 10 x log<sub>10</sub>(Max<sup>2</sup>/MSE)</td><td>Max is the Maximum pixel intensity value</td></tr><tr><td>Mean-squared error (MSE) [11]</td><td>MSE = (1/MxN) &sum;<sub>i=1</sub><sup>M</sup> &sum;<sub>j=1</sub><sup>N</sup> (p<sub>ij</sub> - q<sub>ij</sub>)<sup>2</sup></td><td>p is the cover image pixel and q are the stego image pixel. The image's height and width are denoted by M and N</td></tr><tr><td>Root means square error (RMSE)</td><td>RMSE = &radic;MSE</td><td></td></tr><tr><td>Signal-to-noise ratio (SNR)</td><td>SNR = 10 x log<sub>10</sub>((sum<sup>HxW</sup><sub>i=1</sub> Ci<sup>2</sup>) / (sum<sup>HxW</sup><sub>i=1</sub> (Ci-Si)<sup>2</sup>))</td><td>S is the stego picture, C is the cover image</td></tr><tr><td>Normalized cross correlation (NCC)</td><td>NCC = (sum<sup>HxW</sup><sub>i=1</sub> (Ci-Si)<sup>2</sup>) / (sum<sup>HxW</sup><sub>i=1</sub> Ci<sup>2</sup>)</td><td></td></tr><tr><td>Image fidelity (IF)</td><td>Image Fidelity = 1 - (sum<sup>HxW</sup><sub>i=1</sub> (Ci-Si)<sup>2</sup>) / (sum<sup>HxW</sup><sub>i=1</sub> Ci<sup>2</sup>)</td><td></td></tr><tr><td>Average difference (AD)</td><td>AD = (1/HxW) &sum;<sub>i=1</sub><sup>HxW</sup> (Ci - Si)</td><td></td></tr><tr><td>Structural information change (SSIM)</td><td>SSIM (x, y) = (2&mu;<sub>x</sub>&mu;<sub>y</sub>+C<sub>1</sub>)(2&sigma;<sub>xy</sub>+C<sub>2</sub>) / (&mu;<sub>x</sub><sup>2</sup>+&mu;<sub>y</sub><sup>2</sup>+C<sub>1</sub>)(&sigma;<sub>x</sub><sup>2</sup>+&sigma;<sub>y</sub><sup>2</sup>+C<sub>2</sub>)</td><td>&mu;<sub>x</sub>, &mu;<sub>y</sub> = mean intensities of cover and stego pixel<br>&sigma;<sub>x</sub>, &sigma;<sub>y</sub> = mean intensities of cover and stego image pixel</td></tr><tr><td>Payload</td><td>Payload = Maximum pixel bits on which data embedded</td><td></td></tr></tbody></table>

<table><caption>**Table 6.** Encryption and decryption times</caption><thead><tr><th rowspan="2">Cover Image</th><th colspan="2">Message1.txt</th><th colspan="2">Message2.txt</th><th colspan="2">Message3.txt</th></tr><tr><th>Encryption time</th><th>Decryption time</th><th>Encryption time</th><th>Decryption time</th><th>Encryption time</th><th>Decryption time</th></tr></thead><tbody><tr><td>Image 1</td><td>0.1836</td><td>0.5725</td><td>0.4017</td><td>1.6874</td><td>0.3870</td><td>3.1564</td></tr><tr><td>Image 2</td><td>0.1835</td><td>0.6563</td><td>0.3047</td><td>1.7561</td><td>0.4213</td><td>1.7467</td></tr><tr><td>Image 3</td><td>0.3434</td><td>0.8338</td><td>0.3520</td><td>1.819</td><td>0.5592</td><td>2.303</td></tr></tbody></table>
<table><caption>**Table 7.** Qualitative analysis of the proposed method using various performance metrics</caption><thead><tr><th>Metrics</th><th>Cover Image</th><th>Message1.txt</th><th>Message2.txt</th><th>Message3.txt</th></tr></thead><tbody><tr><td rowspan="3">PSNR</td><td>Image 1</td><td>69.9342</td><td>64.7977</td><td>63.0256</td></tr><tr><td>Image 2</td><td>71.8114</td><td>66.6894</td><td>66.6894</td></tr><tr><td>Image 3</td><td>71.1415</td><td>66.018</td><td>64.2400</td></tr><tr><td rowspan="3">MSE</td><td>Image 1</td><td>0.0066</td><td>0.0215</td><td>0.1799</td></tr><tr><td>Image 2</td><td>0.00428</td><td>0.0139</td><td>0.1180</td></tr><tr><td>Image 3</td><td>0.00499</td><td>0.01626</td><td>0.1565</td></tr><tr><td rowspan="3">RMSE</td><td>Image 1</td><td>0.08125</td><td>0.14677</td><td>0.1799</td></tr><tr><td>Image 2</td><td>0.0654</td><td>0.1180</td><td>0.1180</td></tr><tr><td>Image 3</td><td>0.0707</td><td>0.1275</td><td>0.1565</td></tr><tr><td rowspan="3">SNR</td><td>Image 1</td><td>40.7274</td><td>35.5908</td><td>33.818</td></tr><tr><td>Image 2</td><td>44.6764</td><td>39.554</td><td>39.554</td></tr><tr><td>Image 3</td><td>41.009</td><td>35.8857</td><td>34.1076</td></tr><tr><td rowspan="3">NCC</td><td>Image 1</td><td>0.5672</td><td>0.5672</td><td>0.5672</td></tr><tr><td>Image 2</td><td>0.5347</td><td>0.5347</td><td>0.5347</td></tr><tr><td>Image 3</td><td>0.9365</td><td>0.9365</td><td>0.9365</td></tr><tr><td rowspan="3">IF</td><td>Image 1</td><td>0.4327</td><td>0.4327</td><td>0.4327</td></tr><tr><td>Image 2</td><td>0.4652</td><td>0.4652</td><td>0.4652</td></tr><tr><td>Image 3</td><td>0.0635</td><td>0.0634</td><td>0.0634</td></tr><tr><td rowspan="3">AD</td><td>Image 1</td><td>0.7360</td><td>2.3888</td><td>3.6095</td></tr><tr><td>Image 2</td><td>0.4915</td><td>1.5934</td><td>1.5935</td></tr><tr><td>Image 3</td><td>0.5593</td><td>1.8135</td><td>2.7368</td></tr><tr><td rowspan="3">SSIM</td><td>Image 1</td><td>0.9998</td><td>0.99968</td><td>0.9995</td></tr><tr><td>Image 2</td><td>0.99992</td><td>0.9997</td><td>0.9997</td></tr><tr><td>Image 3</td><td>0.99992</td><td>0.9997</td><td>0.9996</td></tr><tr><td rowspan="3">Payload</td><td>Image 1</td><td>21233664</td><td></td><td></td></tr><tr><td>Image 2</td><td>13824000</td><td></td><td></td></tr><tr><td>Image 3</td><td>18289152</td><td></td><td></td></tr></tbody></table>

between the cover and stego image. The analysis shows fluctuations in AD based on the image and text. The SSIM values close to 1 which makes it a better algorithm performance. As the images in the dataset vary in dimensions and format its capacity of payload differs. Program listings or program commands in the text are normally set in typewriter font:
## 5.4 Comparative Analysis

To compare the results to the proposed method similar constraints were considered. The number of characters (i.e., 34, 54, 73, 100) are taken from the existing method [12]. Comparative analysis is formulated in Table 8.

<table><caption>**Table 8.** Comparison between existing and proposed model</caption><thead><tr><th rowspan="2">Metrics</th><th rowspan="2">Images</th><th rowspan="2">Methods</th><th colspan="4">No. of message char</th></tr><tr><th>34</th><th>54</th><th>73</th><th>100</th></tr></thead><tbody><tr><td rowspan="4">PSNR</td><td rowspan="2">Lina</td><td>Existing [12]</td><td>67.5089</td><td>66.5308</td><td>65.6460</td><td>64.8660</td></tr><tr><td>Proposed</td><td>73.4592</td><td>71.5827</td><td>70.1956</td><td>68.995</td></tr><tr><td rowspan="2">Peppers</td><td>Existing [12]</td><td>67.3644</td><td>66.1365</td><td>65.5089</td><td>64.7647</td></tr><tr><td>Proposed</td><td>73.6439</td><td>71.5918</td><td>70.3678</td><td>69.048</td></tr><tr><td rowspan="2">Mandrill</td><td>Existing [12]</td><td>67.8619</td><td>66.9080</td><td>66.1932</td><td>65.3351</td></tr><tr><td>Proposed</td><td>73.533</td><td>71.6324</td><td>70.3464</td><td>68.9959</td></tr><tr><td rowspan="4">MSE</td><td rowspan="2">Lina</td><td>Existing [12]</td><td>0.0116</td><td>0.0146</td><td>0.0179</td><td>0.0214</td></tr><tr><td>Proposed</td><td>0.00293</td><td>0.00451</td><td>0.00621</td><td>0.0081</td></tr><tr><td rowspan="2">Peppers</td><td>Existing [12]</td><td>0.0120</td><td>0.0160</td><td>0.0184</td><td>0.0219</td></tr><tr><td>Proposed</td><td>0.0028</td><td>0.0045</td><td>0.00597</td><td>0.00809</td></tr><tr><td rowspan="2">Mandrill</td><td>Existing [12]</td><td>0.0107</td><td>0.0134</td><td>0.0157</td><td>0.0192</td></tr><tr><td>Proposed</td><td>0.00288</td><td>0.00446</td><td>0.006</td><td>0.008193</td></tr></tbody></table>

## 6 Conclusion

This work introduces a novel secure communication paradigm with four levels of security using steganography and cryptography, making it impossible for a steg-analyst to read blank text without the secret key to decrypt ciphertext. Security may be achieved via steganography and cryptography, two common techniques. One conceals the communication's existence, while the other modifies the content of the message. Data is encrypted and then transformed into ciphertext using cryptography. Steganography involves embedding data in an image file before exporting it. The rapid development of modern communication necessitates a new security strategy, particularly for computer networks. Due to the open nature of the internet, it appears that there is a chance that the sensitive information supplied may be altered or used to deceive uninformed visitors. As a result, secure communication and information encryption are rapidly expanding.

Additionally, an encryption method can be used more in applications such as military, business, anti-crime, trade and more. Both cryptography and steganography methods offer protection in their own ways but add many layers of security a combination of these methods would be a better offering. In future LSB can be replaced with other steganography methods and more algorithms can be added to further improve security.
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