A Novel approach of Designing E-commerce authentication scheme using Hybrid Cryptography based on Simple symmetric key and extended Linear block cipher algorithm

2020 ◽  
Author(s):  
Prakash Kuppuswamy ◽  
Shanmugasundaram ◽  
Rajan John
Keyword(s):  
Block Cipher ◽  
Authentication Scheme ◽  
Novel Approach ◽  
Symmetric Key ◽  
Linear Block

scholarly journals On the optimality of non-linear computations for symmetric key primitives

2018 ◽  
Vol 12 (4) ◽  
pp. 241-259
Author(s):  
Avik Chakraborti ◽  
Nilanjan Datta ◽  
Mridul Nandi
Keyword(s):  
Block Cipher ◽  
Linear Mapping ◽  
Authenticated Encryption ◽  
Non Linear ◽  
Minimum Number ◽  
Symmetric Key ◽  
Linear Block

Abstract A block is an n-bit string, and a (possibly keyed) block-function is a non-linear mapping that maps one block to another, e.g., a block-cipher. In this paper, we consider various symmetric key primitives with {\ell} block inputs and raise the following question: what is the minimum number of block-function invocations required for a mode to be secure? We begin with encryption modes that generate {\ell^{\prime}} block outputs and show that at least {(\ell+\ell^{\prime}-1)} block-function invocations are necessary to achieve the PRF security. In presence of a nonce, the requirement of block-functions reduces to {\ell^{\prime}} blocks only. If {\ell=\ell^{\prime}} , in order to achieve SPRP security, the mode requires at least {2\ell} many block-function invocations. We next consider length preserving r-block (called chunk) online encryption modes and show that, to achieve online PRP security, each chunk should have at least {2r-1} many and overall at least {2r\ell-1} many block-functions for {\ell} many chunks. Moreover, we show that it can achieve online SPRP security if each chunk contains at least {2r} non-linear block-functions. We next analyze affine MAC modes and show that an integrity-secure affine MAC mode requires at least {\ell} many block-function invocations to process an {\ell} block message. Finally, we consider affine mode authenticated encryption and show that in order to achieve INT-RUP security or integrity security under a nonce-misuse scenario, either (i) the number of non-linear block-functions required to generate the ciphertext is more than {\ell} or (ii) the number of extra non-linear block-functions required to generate the tag depends on {\ell} .

scholarly journals Efficient Implementation of PRESENT and GIFT on Quantum Computers

2021 ◽  
Vol 11 (11) ◽  
pp. 4776
Author(s):  
Kyungbae Jang ◽  
Gyeongju Song ◽  
Hyunjun Kim ◽  
Hyeokdong Kwon ◽  
Hyunji Kim ◽  
...  
Keyword(s):  
Block Cipher ◽  
Search Algorithm ◽  
Block Ciphers ◽  
Quantum Circuits ◽  
Security Level ◽  
Symmetric Key ◽  
Grover Search ◽  
Target Block ◽  
Symmetric Key Cryptography ◽  
Grover Search Algorithm

Grover search algorithm is the most representative quantum attack method that threatens the security of symmetric key cryptography. If the Grover search algorithm is applied to symmetric key cryptography, the security level of target symmetric key cryptography can be lowered from n-bit to n2-bit. When applying Grover’s search algorithm to the block cipher that is the target of potential quantum attacks, the target block cipher must be implemented as quantum circuits. Starting with the AES block cipher, a number of works have been conducted to optimize and implement target block ciphers into quantum circuits. Recently, many studies have been published to implement lightweight block ciphers as quantum circuits. In this paper, we present optimal quantum circuit designs of symmetric key cryptography, including PRESENT and GIFT block ciphers. The proposed method optimized PRESENT and GIFT block ciphers by minimizing qubits, quantum gates, and circuit depth. We compare proposed PRESENT and GIFT quantum circuits with other results of lightweight block cipher implementations in quantum circuits. Finally, quantum resources of PRESENT and GIFT block ciphers required for the oracle of the Grover search algorithm were estimated.

scholarly journals Provably Quantum-Secure Tweakable Block Ciphers

2021 ◽  
pp. 337-377
Author(s):  
Akinori Hosoyamada ◽  
Tetsu Iwata
Keyword(s):  
Polynomial Time ◽  
Provable Security ◽  
Block Cipher ◽  
Block Ciphers ◽  
Quantum Superposition ◽  
Quantum Cryptanalysis ◽  
Classical Setting ◽  
Time Quantum ◽  
Symmetric Key ◽  
Arbitrary Quantum

Recent results on quantum cryptanalysis show that some symmetric key schemes can be broken in polynomial time even if they are proven to be secure in the classical setting. Liskov, Rivest, and Wagner showed that secure tweakable block ciphers can be constructed from secure block ciphers in the classical setting. However, Kaplan et al. showed that their scheme can be broken by polynomial time quantum superposition attacks, even if underlying block ciphers are quantum-secure. Since then, it remains open if there exists a mode of block ciphers to build quantum-secure tweakable block ciphers. This paper settles the problem in the reduction-based provable security paradigm. We show the first design of quantum-secure tweakable block ciphers based on quantum-secure block ciphers, and present a provable security bound. Our construction is simple, and when instantiated with a quantum-secure n-bit block cipher, it is secure against attacks that query arbitrary quantum superpositions of plaintexts and tweaks up to O(2n/6) quantum queries. Our security proofs use the compressed oracle technique introduced by Zhandry. More precisely, we use an alternative formalization of the technique introduced by Hosoyamada and Iwata.

scholarly journals Color Image Encryption using AES and RSA

2020 ◽  
Vol 9 (5) ◽  
pp. 547-550
Keyword(s):  
Data Security ◽  
Block Cipher ◽  
Color Image ◽  
Signal To Noise Ratio ◽  
Security Level ◽  
Change Rate ◽  
The Public ◽  
Key Block ◽  
Symmetric Key ◽  
Encryption Algorithms

Information security is an important task on multimedia and communication world. During storing and sharing maintaining a strategic distance from the outsider access of information is the difficult one. There are many encryption algorithms that can provide data security. In this paper two of the encryption algorithms namely AES and RSA are implemented for color images. AES (Advanced Encryption Standard) is a symmetric key block cipher published in December 2001 by NSIT (National Institute of Standards and Technology). RSA (Rivest-Shamir-Adleman) is an asymmetric key block cipher. It uses two separate keys, one for encryption called the public key and other for decryption called the private key. Both the implementation and analysis are done in Matlab. The quality and security level of both the algorithms is analysed based on various criteria such as Histogram analysis, Correlation analysis, Entropy analysis, NPCR (Number of Pixel Change Rate), UACI (Unified Average Changing Intensity), PSNR (Peak Signal-to-Noise Ratio).

Cryptanalytic Attacks on IDEA Block Cipher

2016 ◽  
Vol 66 (6) ◽  
pp. 582 ◽  
Author(s):  
Harish Kumar Sahu ◽  
Vikas Jadhav ◽  
Shefali Sonavane ◽  
R.K. Sharma
Keyword(s):  
Block Cipher ◽  
Data Encryption ◽  
Secret Key ◽  
Data Confidentiality ◽  
Data Encryption Standard ◽  
Financial Application ◽  
Time Requirements ◽  
International Data ◽  
Key Block ◽  
Symmetric Key

International data encryption algorithm (IDEA) is a secret key or symmetric key block cipher. The purpose of IDEA was to replace data encryption standard (DES) cipher, which became practically insecure due to its small key size of 56 bits and increase in computational power of systems. IDEA cipher mainly to provide data confidentiality in variety of applications such as commercial and financial application e.g. pretty good privacy (PGP) protocol. Till 2015, no successful linear or algebraic weaknesses IDEA of have been reported. In this paper, author explained IDEA cipher, its application in PGP and did a systematic survey of various attacks attempted on IDEA cipher. The best cryptanalysis result which applied to all keys could break IDEA up to 6 rounds out of 8.5 rounds of the full IDEA cipher1. But the attack requires 264 known plaintexts and 2126.8 operations for reduced round version. This attack is practically not feasible due to above mention mammoth data and time requirements. So IDEA cipher is still completely secure for practical usage. PGP v2.0 uses IDEA cipher in place of BassOmatic which was found to be insecure for providing data confidentiality.

scholarly journals Towards Parameterized Shared Key for AVK Approach

Cryptography ◽  
2020 ◽  
pp. 239-256
Author(s):  
Shaligram Prajapat ◽  
Ramjeevan Singh Thakur
Keyword(s):  
Low Power ◽  
Information Exchange ◽  
Sparse Matrix ◽  
Life Time ◽  
Vital Role ◽  
Power Devices ◽  
Power Requirement ◽  
Novel Approach ◽  
Alternative Approach ◽  
Symmetric Key

“Key” plays a vital role in every symmetric key cryptosystem. The obvious way of enhancing security of any cryptosystem is to keep the key as large as possible. But it may not be suitable for low power devices since higher computation will be done for longer keys and that will increase the power requirement which decreases the device's performance. In order to resolve the former specified problem an alternative approach can be used in which the length of key is fixed and its value varies in every session. This is Time Variant Key approach or Automatic Variable Key (AVK) approach. The Security of AVK based cryptosystem is enhanced by exchanging some parameters instead of keys between the communicating parties, then these parameters will be used to generate required keys at the receiver end. This chapter presents implementation of the above specified Mechanism. A model has been demonstrated with parameterized scheme and issues in AVK approach. Further, it has been analyzed from different users' perspectives. This chapter also highlights the benefits of AVK model to ensure two levels of security with characterization of methods for AVK and Estimation of key computation based on parameters only. The characteristic components of recent styles of key design with consideration of key size, life time of key and breaking threshold has also been pointed out. These characteristics are essential in the design of efficient symmetric key cryptosystem. The novel approach of AVK based cryptosystem is suitable for low power devices and useful for exchanging very large objects or files. This scheme has been demonstrated with Fibonacci-Q matrix and sparse matrix based diffused key information exchange procedures. These models have been further tested from perspective of hackers and cryptanalyst, to exploit any weakness with fixed size dynamic keys.

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