scholarly journals 4, 8, 32, 64 bit Substitution Box generation using Irreducible or Reducible Polynomials over Galois Field GF(pq)

Author(s):  
Sankhanil Dey ◽  
Ranjan Ghosh

Substitution Box or S-Box had been generated using 4-bit Boolean Functions (BFs) for Encryption and Decryption Algorithm of Lucifer and Data Encryption Standard (DES) in late sixties and late seventies respectively. The S-Box of Advance Encryption Standard have also been generated using Irreducible Polynomials over Galois field GF(28) adding an additive constant in early twenty first century. In this paper Substitution Boxes have been generated from Irreducible or Reducible Polynomials over Galois field GF(pq). Binary Galois fields have been used to generate Substitution Boxes. Since the Galois Field Number or the Number generated from coefficients of a polynomial over a particular Binary Galois field (2q) is similar to log2q+1 bit BFs. So generation of log2q+1 bit S-Boxes is possible. Now if p = prime or non-prime number then generation of S-Boxes is possible using Galois field GF (pq ), where q = p-1.

2017 ◽  
Author(s):  
Sankhanil Dey ◽  
Ranjan Ghosh

Substitution Box or S-Box had been generated using 4-bit Boolean Functions (BFs) for Encryption and Decryption Algorithm of Lucifer and Data Encryption Standard (DES) in late sixties and late seventies respectively. The S-Box of Advance Encryption Standard have also been generated using Irreducible Polynomials over Galois field GF(28) adding an additive constant in early twenty first century. In this paper Substitution Boxes have been generated from Irreducible or Reducible Polynomials over Galois field GF(pq). Binary Galois fields have been used to generate Substitution Boxes. Since the Galois Field Number or the Number generated from coefficients of a polynomial over a particular Binary Galois field (2q) is similar to log2q+1 bit BFs. So generation of log2q+1 bit S-Boxes is possible. Now if p = prime or non-prime number then generation of S-Boxes is possible using Galois field GF (pq ), where q = p-1.


Author(s):  
Sankhanil Dey ◽  
Ranjan Ghosh

In modern as well as ancient ciphers of public key cryptography, substitution boxes find a permanent seat. Generation and cryptanalysis of 4-bit as well as 8-bit crypto S-boxes is of utmost importance in modern cryptography. In this paper, a detailed review of cryptographic properties of S-boxes has been illustrated. The generation of crypto S-boxes with 4-bit as well as 8-bit Boolean functions (BFs) and Polynomials over Galois field GF(p q ) has also been of keen interest of this paper. The detailed analysis and comparisonof generated 4-bit and 8-bit S-boxes with 4-bit as well as 8-bit S-boxes of Data Encryption Standard (DES) and Advance Encryption Standard (AES) respectively, has incorporated with example. Detailed analysis of generated S-boxes claims a better result than DES and AES in view of security of crypto S-boxes.


Author(s):  
Sankhanil Dey ◽  
Ranjan Ghosh

In modern as well as ancient ciphers of public key cryptography, substitution boxes find a permanent seat. Generation and cryptanalysis of 4-bit as well as 8-bit crypto S-boxes is of utmost importance in modern cryptography. In this paper, a detailed review of cryptographic properties of S-boxes has been illustrated. The generation of crypto S-boxes with 4-bit as well as 8-bit Boolean functions (BFs) and Polynomials over Galois field GF(p q ) has also been of keen interest of this paper. The detailed analysis and comparisonof generated 4-bit and 8-bit S-boxes with 4-bit as well as 8-bit S-boxes of Data Encryption Standard (DES) and Advance Encryption Standard (AES) respectively, has incorporated with example. Detailed analysis of generated S-boxes claims a better result than DES and AES in view of security of crypto S-boxes.


2020 ◽  
Vol 4 (2) ◽  
pp. 9
Author(s):  
Angga Aditya Permana ◽  
Desi Nurnaningsih

Cryptography is the science of maintaining data confidentiality, where the original text (plaintext) is encrypted using an encryption key to be ciphertext (text that has been encrypted). In this case cryptography secures data from a third party so that the third party cannot know the original contents of the data because the one who holds the key for encryption and decryption is only the sender and receiver. There are several cryptographic methods that are commonly used, one of which is DES or Data Encryption Standard. DES is included in the key-symmetric cryptography and is classified as a block cipher type


Author(s):  
Mahadi Winafil ◽  
Sinar Sinurat ◽  
Taronisokhi Zebua

Digital images that are personal and confidential are very vulnerable to wiretapping by irresponsible parties. Especially if distributed via the internet network such as on Facebook, WhatsApp and e-mail chat based applications. Images that are sent sometimes are often confidential images and must be maintained. In order to maintain the security of digital images can be done by utilizing cryptographic techniques. Cryptographic techniques can secure digital images by changing pixel values from digital images so as to produce different pixel values from the original image to be secured. This research will use AES 128 bit and Triple DES methods for encryption and decryption of digital images on client-server based applications. The results of the encryption AES algorithm will be re-encrypted with the Triple DES Algorithm so as to produce pixel values that are far different from the original pixel values. Keywords: cryptography, image, AES, Triple DES


Author(s):  
Mohanad ABDULHAMID ◽  
Nyagathu GICHUKI

This paper presents a comparative study of two cryptosystems, Data Encryption Standard (DES) and the Rivest-Shamir-Adleman (RSA) schemes. DES is a symmetric (or private) key cipher. This means that the same key is used for encryption and decryption. RSA, on the other hand, is an asymmetric (or public) key cipher, meaning that two keys are used, one for encryption and the other for decryption. The objective of this paper is to implement these two schemes in software. The program is written in the Java™ language. It generates a key from a passphrase given by the user, encrypts and decrypts a message using the same key, for the case of DES. In RSA, decryption is done by computing the decryption key from the encryption key. Finally, the program returns the time taken to encrypt and decrypt a message.


2012 ◽  
Vol 67 (12) ◽  
pp. 705-710 ◽  
Author(s):  
Iqtadar Hussain ◽  
Tariq Shah ◽  
Muhammad Asif Gondal ◽  
Hasan Mahmood

In this work, we develop an imperceptible watermarking technique for images that employ substitution boxes constructed over Galois field GF(24). The strength of the proposed substitution box (S-box) is analyzed and its suitability is investigated for watermarking applications by applying statistical methods, which include entropy, contrast, correlation, energy, homogeneity, mean of absolute deviation (MAD), mean square error (MSE), peak-to-peak signal to noise ratio (PSNR), and structural similarity (SSIM) paradigm analysis. The application of the proposed S-box is presented for embedding copyright information in images.


2017 ◽  
Vol 2 (11) ◽  
pp. 17-22
Author(s):  
Sankhanil Dey ◽  
Ranjan Ghosh

Substitution boxes or S-boxes play a significant role in encryption and decryption of bit level plaintext and cipher-text respectively. Irreducible Polynomials (IPs) have been used to construct 4-bit or 8-bit substitution boxes in many cryptographic block ciphers. In Advance Encryption Standard the 8-bit the elements S-box have been obtained from the Multiplicative Inverse (MI) of elemental polynomials (EPs) of the 1st IP over Galois field GF(28) by adding an additive element. In this paper a mathematical method and the algorithm of the said method with the discussion of the execution time of the algorithm, to obtain monic IPs over Galois field GF(pq) have been illustrated with example. The method is very similar to polynomial multiplication of two polynomials over Galois field GF(pq) but has a difference in execution. The decimal equivalents of polynomials have been used to identify Basic Polynomials (BPs), EPs, IPs and Reducible polynomials (RPs). The monic RPs have been determined by this method and have been cancelled out to produce monic IPs. The non-monic IPs have been obtained with multiplication of α where α GF(pq) and assume values from 2 to (p-1) to monic IPs.


2014 ◽  
Vol 1022 ◽  
pp. 104-107
Author(s):  
Hong Ye Li ◽  
Guang Hui Cai ◽  
Hong Chao Sun ◽  
Xiao Cong Ma

With the continuous development of computer networks, security of data is particularly important. AES algorithm is the new data encryption standard after DES algorithm, which has a higher security and faster running speed. Since the promulgation, it has been widely analyzed and multi used around the world. AES algorithm is iterative algorithm,which needs a key generator to generate the encryption and decryption keys for each round.The key generator mainly designs two modules including S box replacement (SubWord) module and Cycle left shift (RotWord) module. After processing results and Rcon array XOR, the key generator may generate an expanded key. The whole design has a simple circuit structure, less resource-intensive, fast running speed advantages, with good prospects for practical applications.


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