Substitution Cipher Research Articles

Triple Key Security Algorithm Against Single Key Attack on Multiple Rounds

In cipher algorithms, the encryption and decryption are based on the same key. There are some limitations in cipher algorithms, for example in polyalphabetic substitution cipher the key size must be equal to plaintext otherwise it will be repeated and if the key is known then encryption becomes useless. This paper aims to improve the said limitations by designing of Triple key security algorithm (TKS) in which the key is modified on polyalphabetic substitution cipher to maintain the size of the key and plaintext. Each plaintext character is substituted by an alternative message. The mode of substitution is transformed cyclically which depends on the current position of the modified communication. Three keys are used in the encryption and decryption process on 8 or 16 rounds with the Exclusively-OR (XOR) of the 1st key. This study also identifies a single-key attack on multiple rounds block cipher in mobile communications and applied the proposed technique to prevent the attack. By utilization of the TKS algorithm, the decryption is illustrated, and security is analyzed in detail with mathematical examples.

GENERAL TECHNOLOGY OF ENCRYPTION AND INTEGRATION OF DATA IN A PATTERN OF A PICTURE OF IMAGES THAT IS RESISTANT TO JPEG COMPRESSION

The object of the thesis is the use of steganographic methods for organizing a covert communication channel in a public channel, providing resistance to lossy compression. The aim of the thesis is to develop an algorithm for embedding data into bitmap images that is resistant to JPEG compression and attacks on the container. In this thesis, the features of the JPEG algorithm are investigated, steganographic methods of information protection are analyzed, and a steganographic algorithm is designed that is resistant to JPEG compression and attacks on the container. Additional security is provided by the polyalphabetic substitution cipher and user secret key used to encrypt the original message. The algorithm was developed using the Python 3 programming language, the NumPy, SciPy, MatPlotLib libraries and the Jupyter Lab package. The task was completed using standard mathematical and statistical methods and tools of the high-level programming language Python 3.

Different Methods of Encryption and Decryption

Abstract: Data is any type of stored digital information. Security is about the protection of assets. Data security refers to protective digital privacy measures that are applied to prevent unauthorized access to computers, personal databases and websites. Cryptography is evergreen and developments. Cryptography protects users by providing functionality for the encryption of data and authentication of other users. Compression is the process of reducing the number of bits or bytes needed to represent a given set of data. It allows saving more data. Cryptography is a popular ways of sending vital information in a secret way. There are many cryptographic techniques available and among them AES is one of the most powerful techniques. The scenario of present day of information security system includes confidentiality, authenticity, integrity, nonrepudiation. The security of communication is a crucial issue on World Wide Web. It is about confidentiality, integrity, authentication during access or editing of confidential internal documents. Keywords: Cryptography, Hill Cipher, Homophonic Substitution Cipher, Monoalphabetic Cipher, Ceaser Cipher.

The Mystery of the Dancing Men

In this paper I describe an activity based on a 1903 Sherlock Holmes murder mystery, in which a substitution cipher is used to encrypt secret messages. The story provides a fun and interesting way to talk about frequency analysis, and can be used as a segue into mathematical constructs such as modular arithmetic and computation. The activity is accessible to ages twelve and above, and has been successfully used in mathematics outreach and popularization efforts as well as in general education and mathematics courses.

An Efficient Cryptosystem Using Playfair Cipher Together With Graph Labeling Techniques

Cryptography is the branch of Discrete Mathematics which deals with the transmission of secret communications between intended parties without the knowledge of third party. Graph theory is the enchanting field if Mathematics that designate integers to edges and vertices through some established functions. In current scenario security of communication plays a crucial role in any telecommunication or network applications. In this paper we have proposed an efficient cryptosystem using play fair cipher together with graph labeling to safeguard our secret text from unauthorised persons. Here we employ the substitution cipher namely Play fair cipher for plaintext encryption and ourencrypted text in the form of Cipher Graph is forwarded to the receiver which on application of graph labeling yields our plaintext. Thus a fusion of the techniques Cryptography with Graph labeling provides ultimate security for secure transmission of data or information at various levels.

A Novel Encryption Approach Based on Vigenère Cipher for Secure Data Communication

Nowadays, with the advancement of technologies in modern life communication and networks, the secrecy of a cryptographic technique has become a strong necessity. The Vernam’s cipher which is a specific form of Vigenere cipher is gaining attention of researchers in the cryptography. But the modern encryption methods based on matrices available in the literature have their limitations to utilize them. Therefore, motivated by numerous cryptographic techniques available in the literature, this study presents a novel encryption approach for secure data communication. The proposed encryption approach is based on Vigenere cipher in finite dimensional vector space. Furthermore, the proposed approach relies on an eternal decomposition which is indiscriminate in the key selection inside key space. To add complexity by text scrambling, a weird substitution cipher key is added to provide maximum derangement in the encrypted text structure. Additionally, in the lights of Shannon’s secrecy, a comparison with usual matrix methods relying on $$LU$$ —decomposition and eigenvalue decomposition is also discussed to justify the perfect secrecy thus achieved. It is revealed that the proposed encryption approach is a more versatile and perfectly secret encryption scheme that roots on the widening of key space to a mathematical structure, which not only fulfills the completeness with respect to the proposed decomposition but identical to message space as well.

A Review on Swarm Intelligence Techniques in Automated Cryptanalysis of Classical Substitution Cipher

Between the year 2006 and 2019, a considerable new and different swarm intelligence techniques have been presented in the literature for automated cryptanalysis of classical substitution cipher. This paper compares the performance of these new and different swarm intelligence techniques. Three main comparison measures are considered to assess the performance of presented swarm intelligence techniques: efficiency, effectiveness, and success rate. To the best of author knowledge first time this kind of review has been carried out. It is noteworthy that among the presented swarm intelligence techniques the performance of cuckoo search technique is best with respect to all the measures.

OB-MECC: An Efficient Confidentiality and Security Enhancement for Cloud Storage System

Cloud computing (CC) is one amongst the developing technologies, which get more attention from academia as well as industries. It offers diverse benefits like sharing computing resources, service flexibility, reducing costs, etc. The Cloud Services Provider (CSP) is accountable for the data that are delivered to the cloud. The threat of seeing the stored data and using sensitive raw data by strangers is the main barrier in the utilization of cloud services. So, Data Security (DS) along with privacy is the chief issue, which is an obstacle while adopting the CC. Countless techniques are existent for ensuring data confidentiality, but they do not completely give protection to the data. To trounce these drawbacks, this paper introduces the Obfuscation (OB) based Modified Elliptical Curve Cryptography (MECC) algorithm for protecting data as of malicious attacks, which is termed as OB-MECC. Primarily, the proposed method obfuscates the data before they are uploaded to the cloud. For the OB of the data, the proposed work employs methods like substitution cipher (SC), position update, Ceaser cipher, binary conversion, 8-bit binary conversion, decimal(), two complex(), and ASCII(). Then, encryption of the obfuscated data is done with the utilization of the MECC algorithm. After encryption, the data on the cloud is retrieved. The retrieved data is then decrypted by reversing the OB and encryption process to get the actual data. The outcomes corroborate that the confidentiality and security level are maximum for the proposed OB-MECC when contrasted to the existing approaches.

Refined Imbricate Cryptography with addition of Polygram Substitution Cipher Method: an enhanced tool for security

The booming of technologies these days make us more comfortable and also take us into the complex world. As information increases rapidly, the level of security also matters. As a technological paradigm, the security can be done using many cryptography techniques. Cryptography is a process of converting a plain text into a cipher text so that the data can be viewed or extracted only by an intended user. In this paper, we describe a methodology inorder to enhance the speed of encryption and decryption process. This process uses ciphertext formation via Imbricate Cryptography and Polygram Substitution Cipher Technique. On performing cryptography, there are a lot of improvements in the actual implementation. Most importantly, the advantage of combining these two algorithms is to make data more secure from the exploiters and also making the computer to process faster.

PENGAMANAN PESAN TEXT DENGAN MENGGUNAKAN KRIPTOGRAFI KLASIK METODE SHIFT CHIPPER DAN METODE SUBSTITUTION CHIPPER

Abstract - The very rapid advancement of telecommunication technology has provided many benefits. With this technology, long distance communication is not an obstacle. One technology that is always used is the sender of messages. At this time, the message application has been used by the community to convey messages to the recipient, the community uses the message application as a communication tool to send messages, the information provided is more precise and is a satisfaction in itself because using message sending application technology is more efficiently received to the recipient. Message content; constitute; security, social, education and professional and entertainment. In history, the Shift Chiper was used during ancient Rome, namely Julius Caesar. the technique used is very simple, namely by shifting each letter in its diplaintext. The main principle of the substitution cipher is to replace each letter on the plaintext into something. Substitution ciphers are incorporated into classical cryptographic algorithms. The idea is to replace one or more letters in plaintext with one or more letters in plaintext with certain rules. These rules are based on the encryption and decryption process. The substitution cipher has many variants or types.

A survey on the Metaheuristics for Cryptanalysis of Substitution and Transposition Ciphers

This paper presents state-of-art cryptanalysis studies on attacks of the substitution and transposition ciphers using various metaheuristic algorithms. Traditional cryptanalysis methods employ an exhaustive search, which is computationally expensive. Therefore, metaheuristics have attracted the interest of researchers in the cryptanalysis field. Metaheuristic algorithms are known for improving the search for the optimum solution and include Genetic Algorithm, Simulated Annealing, Tabu Search, Particle Swarm Optimization, Differential Evolution, Ant Colony, the Artificial Bee Colony, Cuckoo Search, and Firefly algorithms. The most important part of these various applications is deciding the fitness function to guide the search. This review presents how these algorithms have been implemented for cryptanalysis purposes. The paper highlights the results and findings of the studies and determines the gaps in the literature.

Combining Several Substitution Cipher Algorithms using Circular Queue Data Structure

With the revolutionized expansion of the Internet, worldwide information increases the application of communication technology, and the rapid growth of significant data volume boosts the requirement to accomplish secure, robust, and confident techniques using various effective algorithms. Lots of algorithms and techniques are available for data security. This paper presents a cryptosystem that combines several Substitution Cipher Algorithms along with the Circular queue data structure. The two different substitution techniques are; Homophonic Substitution Cipher and Polyalphabetic Substitution Cipher in which they merged in a single circular queue with four different keys for each of them, which produces eight different outputs for every single incoming letter. The present work can be applied efficiently for personal information security and network communication security as well, and the time required for ciphering and deciphering a message is less than 0.1 sec.

Entropy based spatial domain image watermarking and its performance analysis

Digital image watermarking technique based on LSB Substitution and Hill Cipher is presented and examined in this paper. For better imperceptibility watermark is inserted in the spatial domain. Further the watermark is implanted in the Cover Image block having the highest entropy value. To improve the security of the watermark hill cipher encryption is used. Both subjective and objective image quality assessment technique has been used to evaluate the imperceptibility of the proposed scheme.Further, the perceptual perfection of the watermarked pictures accomplished in the proposed framework has been contrasted and some state-of-art watermarking strategies. Test results demonstrates that the displayed method is robust against different image processing attacks like Salt and Peppers, Gaussian filter attack, Median filter attacks, etc.

Cryptobiometrics for the Generation of Cancellable Symmetric and Asymmetric Ciphers with Perfect Secrecy

Security objectives are the triad of confidentiality, integrity, and authentication, which may be extended with availability, utility, and control. In order to achieve these goals, cryptobiometrics is essential. It is desirable that a number of characteristics are further met, such as cancellation, irrevocability, unlinkability, irreversibility, variability, reliability, and biometric bit-length. To this end, we designed a cryptobiometrics system featuring the above-mentioned characteristics, in order to generate cryptographic keys and the rest of the elements of cryptographic schemes—both symmetric and asymmetric—from a biometric pattern or template, no matter the origin (i.e., face, fingerprint, voice, gait, behaviour, and so on). This system uses perfect substitution and transposition encryption, showing that there exist two systems with these features, not just one (i.e., the Vernam substitution cipher). We offer a practical application using voice biometrics by means of the Welch periodogram, in which we achieved the remarkable result of an equal error rate of (0.0631, 0.9361). Furthermore, by means of a constructed template, we were able to generate the prime value which specifies the elliptic curve describing all other data of the cryptographic scheme, including the private and public key, as well as the symmetric AES key shared between the templates of two users.

Comparison between integer splitting cipher and traditional substitution ciphers, based on modular arithmetic

The integer splitting cipher is a special mathematical method that is proposed by the author and it can be considered as a generalization of modular arithmetic operation. In this cipher, each plaintext character is replaced on the base of another integer number with a sequence of k integers (k-splitting level) by the usage of modular arithmetic, so this cipher can be classified under substitution ciphers that are used the modular arithmetic during the encryption process. In this article the main differences among splitting cipher and four traditional substitution ciphers, which are Caesar, Vigenère, Affine and Hill, will be listed and as a conclusion we can notice that the splitting method complicate the statistical and semantic restoration of the plaintext from the point view of an unauthorized user. Furthermore, the decryption process of the splitting cipher meets the goal of Chinese reminder theorem, which states that it can recover an integer from a unique set of its residues modulo, so a comparison is conducted to show the main differences between the integer splitting theories and the Chinese remainder theorem.

New symmetric key cipher capable of digraph to single letter conversion utilizing binary system

In this paper, a new Playfair cipher built on bits level symmetric key cryptographic was proposed for the purpose of converting pairs of letters (digraphs) into single letters. The proposed algorithm is capable to overcome many of the shortcoming and vulnerabilities that exist in the current classical version of Playfair algorithm. The Playfair cipher is exceedingly complex than a classical substitution cipher, but still simple to hack using automated tactics. It is famous as a digraph cipher because two letters are exchanged by other two letters. This destroys any solo letter occurrence statistics, but the digraph statistics still unaffected (frequencies of two letters). Unluckily letter pairs have a flatter distribution than the one letter frequencies, so this intricacy matters for solving the code using pen and paper procedures. The suggested encryption process is conducted as follows; letters are first arranged in a spiral manner in Polybius square, afterwards, each pair will be replaced utilizing before-after technique if we are arranging pairs horizontally and down-up technique (vertically). The former process produces pairs of Plaintext that will be converted to binary bit stream then will be divided over blocks with stable sizes. Bits of these blocks are taken from pairs then fit them into square matrix of suitable order to put the concept of row-wise and revers row-wise matrix. Bits of this matrix are split into 2x2 square matrixes. The sub-matrixes are formed 8 bits. Here the XNOR operation is taken into consideration for bitwise operation to generate the keys for decryption and produce the cipher-text.

Lightweight Coap Based Authentication Scheme by Applying Two-Way Encryption for Secure Transmission

With the widespread popularity of the Internet of Things (IoT), different sectors-based applications are increasingly developed. One of the most popular application layer protocols is the Constrained Application Protocol (CoAP), and the necessity of ensuring data security in this layer is crucial. Moreover, attackers target the vulnerabilities of IoT to gain access to the system, which leads to a security threat and violate privacy. Typically, user authentication and data encryption are applied for securing data communication over a public channel between two or more participants. However, most of the existing solutions use cryptography for achieving security, with the exception of high computation cost. Hence, these solutions fail to satisfy the resource-constrained characteristics of IoT devices. Therefore, a lightweight security mechanism is required for achieving both secure transmission and better performance. This paper proposes a Lightweight Authentication with Two-way Encryption for Secure Transmission in CoAP Protocol (LATEST) that provides a secure transmission between the server and IoT devices. This mutual authentication mechanism uses ROT 18 Cipher with XoR operation and 128-bit AES based encryption for securing the data transmission. The ROT18 Cipher is a monoalphabetic substitution cipher, which is a combination of ROT13 and ROT5. The proposed scheme employs symmetric encryption in both client and server for ensuring secure authentication and mutually confirm each other identity. In addition, the proposed LATEST scheme ensures confidentiality and integrity by being resistant to replay attacks, impersonation attacks, and modification attacks. The experimental evaluation demonstrates that the proposed LATEST scheme is lightweight and provides better security compared to the existing scheme.

Securing Digital Color Image based on Hybrid Substitution Cipher

This study proposes securing digital color images with hybrid substitution cryptographic methods combined with the Vigenere and Beaufort methods. The hybrid process is carried out using the help of two randomly generated keys. The first key is a matrix with an 8-bits value and the second key is a matrix with a binary value. The binary key is used to determine the Vigenere or Beaufort process, while the 8-bit key is used for modulus operations based on the Vigenere or Beaufort algorithm. At the test stage used a standard image that has an RGB color channel as a dataset. The quality of the cryptographic method is measured by several measuring instruments such as MSE, PSNR, and SSIM to determine the quality of encryption visually and the perfection of decryption, besides that it is used Entropy, NPCR and UACI to determine the probability of encryption resistance and quality against differential attacks. The TIC TOC function is also used to measure the computing speed of the encryption and decryption process. Measurement results using all measuring instruments indicate that the proposed method has very satisfying results and has fast computing. Keywords – Cryptography, Substitution Cipher, Modulus Function, Encryption, Decryption, Image Transmission

Ciphering and Deciphering Messages by Graph Labeling Techniques Through Multilevel Cryptosystem

In this paper we present an upgraded technique of coding a message using Multilevel Cryptosystem based on Four square Cipher, Mono alphabetic Substitution Cipher and Columnar Transposition cipher subjected to Graph labeling. We send our Cipher text in the form of graph pattern which admits Root cube mean labeling. Further by using the secret key the receiver decrypts the edge labels which is shared by the sender. Here we employ Symmetric key cryptosystem for both encryption and decryption of messages as both the sender as well as thereceiver shares the same key for encryption and decryption of messages. In this research work we performed Multilevel Cryptographic technique together with Graph Labeling concept to save the messages from third party or Hackers ensuring secure transmission of messages

New Polyalphabetic Substitution Scheme for Secure Communication

The internet is a very powerful and useful tool for communication, information and connectivity. So it is very important to keep yourself safe and secure online. The best way of secure information is encryption; there are many cryptographic algorithms available for encryption. These cryptographic algorithms are classified according to their encrypting process; as substitution cipher or transposition cipher. In Polyalphabetic ciphers, the substitution rule changes continuously from character to character according to the keyword and plaintext. Vigenere cipher is considered to be the most efficient Polyalphabetic substitution cipher. But it is vulnerable to attacks, due to its repeating nature of the keyword. To overcome this vulnerability, here we are presenting a new Polyalphabetic substitution scheme which uses infinite number of 26 x 26 random tables for encryption. During encryption, whenever the keyword repeats, this proposed Polyalphabetic substitution cipher generates a 26 x 26 alphabetical random table. Instead of using the same Vigenere Table here we are using an infinite number of alphabetical tables depending on the length of the plaintext and keyword. Each random table will be completely independent from the previous table. This will reduces the repeating sequences in the ciphertext. The repeating nature of the keyword does not help the crackers to break this code. So this proposed Polyalphabetic substitution cipher is considered as an unbreakable cryptosystem. The Proposed Polyalphabetic cipher can provide security for many applications such as web transactions, web transactions, personal emails, secret information transmitted between public or private organization, military application etc.