Proposing of Developed Advance Encryption Standard

A modified XXTEA “M-XXTEA” symmetric block cipher that has a simple construction compared to the advanced encryption standard (AES) is proposed. It is efficient for protecting limited-resource devices such as IoT smart devices. The M-XXTEA will be able to achieve confidentiality during transmission of data over the internet. Since the original XXTEA was vulnerable against key-related and chosen-plaintext attacks. Therefore, this paper introduces a new and robust version of the original XXTEA by employing an improved S-box to enhance security to overcome such types of attacks. Besides, the M-XXTEA is coupled with a chaotic key generator system adding a layer of security achieving the idea behind the one-time pad. The cipher keys are dynamically changing for each block of plaintext when encrypted. Thus, it provides a more robust security mechanism than the original XXTEA and the AES. Besides enhancing data security, the M-XXTEA can function with different sizes of text blocks and with different key sizes. Several experiments are implemented to compare the performance of the M-XXTEA with the original XXTEA and with the AES. Results show that the M-XXTEA encryption and decryption time efficiencies outperform AES by 60%. Besides, the M-XXTEA achieves speed efficiency 57% better than the AES. It can be used efficiently for protecting IoT smart devices in the industry, and e-health systems, and smart cities.

Based on the different representations of the finite field GF(256), there are different Advanced Encryption Standard (AES) implementations, which is called dual ciphers. They have the same encryption process as AES, but with parameters modified. The research of dual ciphers initially aims to find more efficient AES implementations, and later it is found that they can be used to resist side-channel attacks and for white box ciphers. In this paper, based on the rotation of columns, we propose new AES dual ciphers, which use AES directly, but with the input matrices (plaintexts and keys) and output matrix rotated. The key expansion algorithm only needs some change on the computation sequence. Because of these features, there is almost no extra cost in implementing dual ciphers and it is easy for new dual ciphers to work with other side-channel protection methods to protect AES in more dimensions.

The main topic of this thesis is related to the state of the art in designing cryptographic primitives from a hardware point of view. A special emphasis is dedicated to low-power/low-energy CMOS design. A set of solutions is proposed including an LFSR based stream cipher with self-synchronizing capabilities, a new memory-less Rijndael block cipher architecture and a public key scheme in the class of discrete logarithm. The former is based on arithmetic in large finite field, mainly Galois extension field GF(2‴). These solutions are droved using low-energy techniques, in order to decrease both the switching activity and the total delay. The fundamental motivation supporting this work, is to demonstrate that practical solutions can be obtained for implementing such complex primitives in large scaled circuits, that arc at once, high performance architectures (low-power, high-speed) and cryptographicaly strong, using the well known trade-off between area-speed or area-power. Security constraint has been duly considered, mainly by increasing the key-size. In this work, we explore the general aspects of designing the above mentioned cryptographic functions. We give an extensive survey of some cryptographic primitives from the hardware point of view and expose their security properties. The thesis favours stream cipher and public-key schemes, as currently the most promising advance to capture the notion of key generation and establishment and data bulk encryption. One contribution is the convenient notation for expressing cryptographic self-synchronizing stream ciphers SSSC schemes and our SSMG proposal, a scheme based on packet fingerprint identification, that relies on keyed cryptographic hash function to achieve the security requirements. We maintain an important distinction between hardware implementation and algorithm's security, because the security of cryptographic primitives cannot be based on mathematically strong functions only but requires an extensive cryptanalysis at different levels including the application. This causes a concern for a formalization of the security of an implemented cryptographic primitive. Nevertheless, while some schemes arc well known to be secure such as DL based public key schemes and enough cryptanalyzed such as the new standard Rijndael, some security aspects of the SSMG are discussed. A part of this work studies the specific aspects related to hardware implementation of Rijndael block cipher, the new standard designed to be a substitute for DES. An efficient architecture is developed targeting FPGA implementation, by simply avoiding memory blocks dedicated to the implementation of S-boxes and replacing them by on-chip forward computation using composite Galois field. This technique helps to reduce considerably the amount of hardware required at the cost of little increase of the switching activity. The main conclusion is that, while security constraint of cryptographic primitives increases the hardware complexity and reduces the performances, practical solutions exist for reducing such complexities while keeping or increasing the level of security. Nevertheless, major open questions remain both for a firm theoretical foundation and the proper cryptanalysis of certain solutions.

This paper presents original research results that show viable options for implementation of the advanced encryption standard (AES) cipher (both encoding and decoding paths) in low cost field programmable gate arrays (FPGA). The discussion begins with those aspects of the four basic cipher transformations that are essential for realisation with resources available in FPGA devices, then moves to various possible organisations of the cipher unit and concludes with efficiency and size comparison of results obtained after implementation of the AES-128 version of the method in Spartan-3 devices from Xilinx. The compared design options were implemented with a standard and widely used ISE software with XST synthesis tool. No hand optimisation or fine-tuning of the implementation steps were performed: the synthesis, mapping, placement and routing were all done fully automatically by the software. While this approach will always be inferior to the top-performance hand-optimised designs known in the literature, its automatic implementation brings specific advantages in projects where the unit must co-exist with other parts of the system and elaborated optimisations are either limited or undesired.

Problem statement: Mobile Ad-hoc Network is infrastructureless network supported by no fixed trusted infrastructure. The packets had a chance to drop or hacked by eavesdropper during transmission. So, encryption method is required for sending and receiving packet in secret manner. Approach: In this approach, the block and key size had been increased by 256 bits. When compared to Rijndael algorithm, it was more secure and effective. To attain security goals like: authentication, integrity, non- repudation, privacy, a secret key was necessary to be shared between the sender and receiver. For data communication, we use MAC address for exchanging packet with encrypted key exchange system. Results: For encryption, In Rijndael algorithm the whole data had to be run twice but our proposed algorithm would encrypt the whole data and run once. The encryption was done with neighborhood key and with message specific key for the enhancement of security. Conclusion: In our algorithm, the time required to break an encryption scheme is excessive as the key size is larger. Here the security is focusing the application level. The forward and backward security is ensured with neighborhood and with message specific key for the route discovery.

In this book we have been discussing polynomial equations over finite fields of characteristic two for quite some time. However, the finite field in question has almost always been \(\mathbb{G}\mathbb{F}\)(2). In cryptanalysis, this is usually the field of interest, with notable exceptions, including several ciphers: Rijndael [89] which later become the Advanced Encryption Standard (AES), which uses \(\mathbb{G}\mathbb{F}\)(256); the cryptosystem called TTM [127], over the same field; the Courtois Toy Cipher (CTC) [14] [73], can be modeled over \(\mathbb{G}\mathbb{F}\)(8) for certain settings. The stream cipher family QUAD [42] can operate over any finite field, but finite fields of characteristic two would be the natural setting (see Section 5.2 on Page 66).

In this chapter we extend beyond integers modulo primes to consider finite fields of characteristic 2. For a more extensive presentation of finite fields, the reader should consult Lidl and Niederreiter [1]. For a different presentation of finite fields of characteristic 2, the reader could consult Golomb [2]. Finite field arithmetic in characteristic 2 is used in the Advanced Encryption Standard (AES). It can be preferable in other cryptosystems, because computer hardware works in binary, and thus the underlying arithmetic operations needed to encrypt and decrypt can be very fast.

Daily activities have been increasingly supported by intelligent devices and applications. Smart devices are constantly communicating through the Internet of Things (IoT) networks, either by sending collected data and notifying the actions taken or by receiving instructions for actions to be taken. Most of this communication requires the confidentiality of data through the usage of encryption algorithms, being the Advanced Encryption Standard (AES) algorithm one of the most used. However, how do the operation modes of AES algorithm perform in a resource-constraint device? This paper aims to evaluate the impact on the time to encrypt and decrypt different sized messages in IoT devices when using each one of the five AES modes of operation and the three key sizes defined. The test scenario was implemented using two programming languages, running on a Raspberry Pi device. The results achieved infers that Python was quicker and had a more homogeneous result set than JavaScript implementation in most AES operation modes. These results help to understand the trade-off between IoT devices' security needs and delays in communication caused by the selection of the AES algorithm operation mode.

Chapter 9 - Basics of Cryptography

A new LabVIEW simulation design was applied to provide a comparison study among several types of the most common symmetric and asymmetric encryption algorithms. Also, the comparison with advanced encryption package program was made. The results showed that the new LabVIEW simulation design had advantages in several points, where the evaluated time required for the encryption and decryption processes will be lesser than it values using advanced encryption package program.In this work, the symmetric encryption algorithms were used: AES (Advanced Encryption Standard), DES (Data Encryption Standard), 3DES (Triple Data Encryption Standard) and RC2 (Rivest Cipher) algorithms, while the asymmetric encryption algorithm used was the RSA (Rivest-Shamir-Aldeman) algorithm. The comparison had been achieved using different sizes of text files with different key sizes. The final results proved that the LabVIEW simulation design is better than the Advanced Encryption Package because it increased the algorithm’s performance by 65% in terms of speed and throughput, and for the algorithms’ comparison, the final results showed the effectiveness of AES algorithm over the other algorithms in terms of speed and throughput for the encryption and decryption processes.

Wireless Sensor Network is the remote accessible network or the implementation of the network in the unattainable area to gather data from sensor nodes. The data from the network in wireless mesh topology is less secured based on the security features implemented. Any communication between the nodes are through the other nodes in the network. These motes in the network are restricted to memory and energy issues. Algorithms like symmetric key methods Ron Rivest, Adi Shamir and Leonard Adleman Algorithm (RSA) and Advanced Encryption Standard (AES) are used. It has less efficiency in terms of computation and memory size. It is also harder to implement in the Hop by hop protocol where the authenticity of the message need to pass from one node to the other with limited memory and energy where the need for security is high. So for better effective security and authentication we go for the Elliptic curve cryptography(ECC) algorithm. This method is more efficient with the key size and also more secure in terms. It is less vulnerable to security threat attacks. Modified effective implementing enhanced ECC with a features like Elliptic Curve Digital Signature Algorithm (ECDSA) in to add more secure and effective data transfer along with the key cipher of the text information.

Energy-efficient and security-optimized AES hardware design for ubiquitous computing

Four Dimensional (4D) Playfair cipher fused with Linear Feedback Shift Register (LFSR) has the capability of providing confidentiality to any type of data. The main aim of this research is to compare this cipher with the standard ciphers AES-256 and RSA-2048. The comparisons are done on the basis of encryption and decryption times, plain data size versus cipher data size, possible number of keys and types of data supported. It is found from the comparison analysis that the AES-256 is efficient in terms of time, memory and bandwidth consumption when compared to the other two ciphers. For AES-256, data size has to be a multiple of 16 bytes or padded values shouldn’t be a part of original data values in order to be unambiguous while the other two ciphers are always unambiguous. Also, AES-256 is weak against brute force attack when compared to other two ciphers. Among RSA-2048 and 4D Playfair cipher fused with LFSR, latter is highly efficient in terms of time, memory and bandwidth. Therefore, applications wanting to secure all sorts of data efficiently and unambiguously irrespective of data size can use 4D Playfair cipher fused with LFSR. Keywords: Data security; Cryptography; AES; RSA; 4D Playfair cipher

Methods of finding multiplicative inverses in GF(2 8)

Rijndael is a substitution-permutation network (SPN) block cipher for the AES development process. Its block and key sizes range from 128 to 256 bits in steps of 32 bits, which can be denoted by Rijndael-$b$-$k$, where $b$ and $k$ are the block and key sizes, respectively. Among them, Rijndael-128-128/192/256, that is, AES, has been studied by many researchers, and the security of other large-block versions of Rijndael has been exploited less frequently. However, more attention has been paid to large-block versions of block ciphers with the fast development of quantum computers. In this paper, we propose improved impossible differential attacks on 10-round Rijndael-256-256, 10-round Rijndael-224-256, and 9-round Rijndael-224-224 using precomputation tables, redundancies of key schedules, and multiple impossible differentials. For 10-round Rijndael-256-256, the data, time, and memory complexities of our attack were approximately $2^{244.4}$ chosen plaintexts, $2^{240.1}$ encryptions, and $2^{181.4}$ blocks, respectively. For 10-round Rijndael-224-256, the data, time, and memory complexities of our attack were approximately $2^{214.4}$ chosen plaintexts, $2^{241.3}$ encryptions, and $2^{183.4}$ blocks, respectively. For 9-round Rijndael-224-224, the data, time, and memory complexities of our attack are approximately $2^{214.4}$ chosen plaintexts, $2^{113.4}$ encryptions, and $2^{87.4}$ blocks, respectively, or $2^{206.6}$ chosen plaintexts, $2^{153.6}$ encryptions, and $2^{111.6}$ blocks, respectively. To the best of our knowledge, our results are currently the best on Rijndael-256-256 and Rijndael-224-224/256.