A novel bit level block cipher based symmetric key cryptographic technique using G.C.D is proposed in this research paper. Entire plain text file is read one character at a time and according to the binary representation of ASCII value of the characters, entire plain text file is divided into n number of 16 bit blocks. Then an agreed-upon symmetric key file is formed by dividing each 16 bit block into two 8 bit sub blocks and by using Greatest Common Divisor (G.C.D) operation among them. The key size is 40 times the number of 16 bit blocks present in the plain text file as each block produces a key of size 40 bits. The character corresponding to the G.C.D value for each block is stored in the cipher text file which is sent by the sender to the receiver along with the symmetric key file. From the symmetric key file and the cipher text file, the receiver by applying reverse procedure, gets back the original plain text file. This technique has several merits, some of them are formation of symmetric key file dynamically, achievement of 50% compression rate in the cipher text file, better security in terms of brute force attack and applicability of the technique for a large number of files of different size and type.
This paper describes a novel bit level stream cipher based symmetric key cryptographic technique. At first, sender and receiver agree upon a symmetric key. Then the symmetric key is formed using Greatest Common Divisor (G.C.D) of sum of even or odd bit positional weightth even or odd number and a symmetric key value is derived from the symmetric by the sender. The symmetric key value is XORed with the ASCII value of the plain text character to get the cipher text character. This is repeated for the entire plain text file. The symmetric key and the entire cipher text file is sent by the sender …
In a world heavily loaded by information, there is a great need for keeping specific information secure from adversaries. The rapid growth in the research field of lightweight cryptography can be seen from the list of the number of lightweight stream as well as block ciphers that has been proposed in the recent years. This paper focuses only on the subject of lightweight block ciphers. In this paper, we have proposed a new 256 bit lightweight block cipher named as Marvin, that belongs to the family of Extended LS designs.
The contribution of Stream ciphers to cryptography is immense. For fast encryption, stream ciphers are preferred to block ciphers due to their XORing operation, which is easier and faster to implement. In this paper we present a matrix based stream cipher, in which a m x n binary matrix single handedly performs the work of m parallel LFSRs. The resistivity of the proposed stream cipher to various possible attacks are analyzed. Interestingly the output of the matrix multiplication can otherwise be used as a parallel bit/byte generator, useful for encrypting video streams.
We introduce NSABC/w -- Nice-Structured Algebraic Block Cipher using w-bit word arithmetic, a 4w-bit analogous of Skipjack [NSA98] with 5w-bit key. The Skipjack's internal 4-round Feistel structure is replaced with a w-bit, 2-round cascade of a binary operation (x,z)\mapsto(x\boxdot z)\lll(w/2) that permutes a text word x under control of a key word z. The operation \boxdot, similarly to the multiplication in IDEA [LM91, LMM91], bases on an algebraic group over w-bit words, so it is also capable of decrypting by means of the inverse element of z in the group. The cipher utilizes a secret 4w-bi…
This paper deals with the merger of the two lightweight stream ciphers: A5by1 and Trivium. The idea is to make the key stream generation more secure and to remove the attacks of the individual algorithms. The bits generated by the Trivium cipher will act as the input of the A5by1 cipher. The registers used in the A5by1 cipher will be filled by the output bits of the Trivium cipher. The three registers will then be connected to generate an output which will be our required key stream.
This paper presents the hardware design and analysis of ACE and WAGE, two candidate ciphers for the NIST Lightweight Cryptography standardization. Both ciphers use sLiSCP's unified sponge duplex mode. ACE has an internal state of 320 bits, uses three 64 bit Simeck boxes, and implements both authenticated encryption and hashing. WAGE is based on the Welch-Gong stream cipher and provides authenticated encryption. WAGE has 259 bits of state, two 7 bit Welch-Gong permutations, and four lightweight 7 bit S-boxes. ACE and WAGE have the same external interface and follow the same I/O protocol to tran…
The XCRUSH family of non-Feistel, ARX block ciphers is designed to make efficient use of modern 64-bit general-purpose processors using a small number of encryption rounds which are simple to implement in software. The avalanche function, which applies one data-dependent, key-dependent rotation per 64-bit word of plaintext per round, allows XCRUSH to achieve an almost totally diffuse 256-bit block after just the first two rounds. Designed for speed in software, 3-round XCRUSH is measured at ~7.3 cycles/byte single-threaded on an Intel Haswell processor. A pseudorandom number generator, constru…
This article presents a new algorithm to find MDS matrices that are well suited for use as a diffusion layer in lightweight block ciphers. Using an recursive construction, it is possible to obtain matrices with a very compact description. Classical field multiplications can also be replaced by simple F2-linear transformations (combinations of XORs and shifts) which are much lighter. Using this algorithm, it was possible to design a 16x16 matrix on a 5-bit alphabet, yielding an efficient 80-bit diffusion layer with maximal branch number.
In this paper the author presents a new cryptographic technique to exclude the repetitive terms in a message, when it is to be encrypted, so that it becomes almost impossible for a person to retrieve or predict the original message from the encrypted message. In modern world, cryptography hackers try to break a code or cryptographic algorithm or try to retrieve the key, which is needed to encrypt a message, by analyzing the insertion or presence of repetitive bits / characters (bytes) in the message and encrypted message to find out the encryption algorithm or the key used for it. So it is mus…
Lightweight block ciphers have been widely used in applications such as RFID tags, IoTs, and network sensors. Among them, with comparable parameters, the Light Encryption Device (LED) block cipher achieves the smallest area. However, implementation of encryption algorithms manifest side-channel leakage, therefore, it is crucial to protect their design against side-channel analyses. In this paper, we present a threshold implementation of the LED cipher which has 64-bit data input and 128-bit key. The presented design splits secret information among multiple shares to achieve a higher security l…
A common approach to protect confidential information is to use a stream cipher which combines plain text bits with a pseudo-random bit sequence. Among the existing stream ciphers, Non-Linear Feedback Shift Register (NLFSR)-based ones provide the best trade-off between cryptographic security and hardware efficiency. In this paper, we show how to further improve the hardware efficiency of Grain stream cipher. By transforming the NLFSR of Grain from its original Fibonacci configuration to the Galois configuration and by introducing a clock division block, we double the throughput of the 80 and 1…
The technique considers a message as binary string on which a Efficient Cryptographic Protocol using Recursive Bitwise amd pairs of Bits of operation (RBPBO) is performed. A block of n bits is taken as an input stream, where n varies from 4 to 256, from a continuous stream of bits and the technique operates on it to generate the intermediate encrypted stream. This technique directly involves all the bits of blocks in a boolean operation and a session key. The same operation is performed repeatedly for different block sizes as per the specification of a session key to generate the final encrypt…
The $r$-rounds Even-Mansour block cipher is a generalization of the well known Even-Mansour block cipher to $r$ iterations. Attacks on this construction were described by Nikolić et al. and Dinur et al., for $r = 2, 3$. These attacks are only marginally better than brute force, but are based on an interesting observation (due to Nikolić et al.): for a "typical" permutation $P$, the distribution of $P(x) \oplus x$ is not uniform. This naturally raises the following question. Call permutations for which the distribution of $P(x) \oplus x$ is uniform "balanced." Is there a sufficiently large fami…
Security in embedded systems has become a main requirement in modern electronic devices. The demand for low-cost and highly secure cryptographic algorithms is increasingly growing in fields such as mobile telecommunications, handheld devices, etc. In this paper, we analyze and evaluate the development of cheap and relatively fast hardware implementations of the KATAN family of block ciphers. KATAN is a family of six hardware oriented block ciphers. All KATAN ciphers share an 80-bit key and have 32, 48, or 64-bit blocks. We use VHDL under Altera Quartus in conjunction with ModelSim to implement…
Parallel supercomputer-based Monte Carlo and stochastic simulations require pseudorandom number generators that can produce distinct pseudorandom streams across many independent processes. We propose a scalable class of parallel and vectorizable pseudorandom number generators based on a non-cryptographic version of the RSA public-key exponentiation cipher. Our method generates uniformly distributed IEEE double-precision floating point pseudorandom sequences on $[0,1)$ by encrypting pseudorandom sequences of 64-bit integer messages by modular exponentiation. The advantages of the method are: th…
In this paper, a new stream cipher is designed as a clock-controlled one, but with a new mechanism of altering steps based on system theory in such a way that the structures used in it are resistant to conventional attacks. Our proposed algorithm (PALS) uses the main key with the length of 256 bits and a 32-bit message key. The most important criteria considered in designing the PALS are resistance to known attacks, maximum period, high linear complexity, and good statistical properties. As a result, the output keystream is very similar to the perfectly random sequences and resistant to conven…
Linear (or differential) cryptanalysis may seem dull topics for a mathematician: they are about super simple invariants characterized by say a word on n=64 bits with very few bits at 1, the space of possible attacks is small, and basic principles are trivial. In contract mathematics offers an infinitely rich world of possibilities. If so, why is that cryptographers have ever found so few attacks on block ciphers? In this paper we argue that black-box methods used so far to find attacks in symmetric cryptography are inadequate and we work with a more recent white-box algebraic methodology. Inva…
We present a new quasigroup based block encryption system with and without cipher-block-chaining. We compare its performance against Advanced Encryption Standard-256 (AES256) bit algorithm using the NIST statistical test suite (NIST-STS) that tests for randomness of a sequence. Since it is well known that a good encryption algorithm must destroy any statistical properties of the input sequence and produce an output close to a true random sequence, the NIST-STS suite results provide a good test bench. In almost all tests from the suite the proposed algorithm performs better than AES256.
Considering the prospects of public key embedding (PKE) mechanism in active forensics on the integrity or identity of ciphertext for distributed deep learning security, two reversible data hiding in encrypted domain (RDH-ED) algorithms with PKE mechanism are proposed, in which all the elements of the embedding function shall be open to the public, while the extraction function could be performed only by legitimate users. The first algorithm is difference expansion in single bit encrypted domain (DE-SBED), which is optimized from the homomorphic embedding framework based on the bit operations o…
In this paper, we report the first quantum key-recovery attack on a symmetric block cipher design, using classical queries only, with a more than quadratic time speedup compared to the best classical attack. We study the 2XOR-Cascade construction of Gaži and Tessaro (EUROCRYPT~2012). It is a key length extension technique which provides an n-bit block cipher with 5n/2 bits of security out of an n-bit block cipher with 2n bits of key, with a security proof in the ideal model. We show that the offline-Simon algorithm of Bonnetain et al. (ASIACRYPT~2019) can be extended to, in particular, attack …
The protection of confidential information is a global issue and block encryption algorithms are the most reliable option. The famous information theorist, Claude Shannon has given two desirable characteristics that should exist in a strong cipher which are substitution and permutation in their fundamental research on Communication Theory of Secrecy Systems. block ciphers strictly follow the substitution and permutation principle to generate a ciphertext. The actual strength of the block ciphers against several attacks is entirely based on its substitution characteristic, which is gained by us…
Recent years have shown that more than ever governments and intelligence agencies try to control and bypass the cryptographic means used for the protection of data. Backdooring encryption algorithms is considered as the best way to enforce cryptographic control. Until now, only implementation backdoors (at the protocol/implementation/management level) are generally considered. In this paper we propose to address the most critical issue of backdoors: mathematical backdoors or by-design backdoors, which are put directly at the mathematical design of the encryption algorithm. While the algorithm …
The advances of the Internet of Things (IoT) have had a fundamental impact and influence in sharping our rich living experiences. However, since IoT devices are usually resource-constrained, lightweight block ciphers have played a major role in serving as a building block for secure IoT protocols. In CHES 2015, SIMECK, a family of block ciphers, was designed for resource-constrained IoT devices. Since its publication, there have been many analyses on its security. In this paper, under the one bit-flip model, we propose a new efficient fault analysis attack on SIMECK ciphers. Compared to those …
Ineffective Fault Analysis (SIFA) was introduced as a new approach to attack block ciphers at CHES 2018. Since then, they have been proven to be a powerful class of attacks, with an easy to achieve fault model. One of the main benefits of SIFA is to overcome detection-based and infection-based countermeasures. In this paper we explain how the principles of SIFA can be applied to GIMLI, an authenticated encryption cipher participating the NIST-LWC competition. We identified two possible rounds during the intialization phase of GIMLI to mount our attack. If we attack the first location we are ab…
Simeck, a lightweight block cipher has been proposed to be one of the encryption that can be employed in the Internet of Things (IoT) applications. Therefore, this paper presents the security of the Simeck32/64 block cipher against side-channel cube attack. We exhibit our attack against Simeck32/64 using the Hamming weight leakage assumption to extract linearly independent equations in key bits. We have been able to find 32 linearly independent equations in 32 key variables by only considering the second bit from the LSB of the Hamming weight leakage of the internal state on the fourth round o…
- In this paper a session based symmetric key encryption system has been proposed and is termed as Permutated Cipher Technique (PCT). This technique is more fast, suitable and secure for larger files. In this technique the input file is broken down into blocks of various sizes (of 2 power n order) and encrypted by shifting the position of each bit by a certain value for a certain number of times. A key is generated randomly wherein the length of each block is determined. Each block length generates a unique value of number of bits to be skipped. This value determines the new position of the bi…
In this paper, we propose a session based bit level symmetric key cryptographic technique and it is termed as Spiral Matrix Based Bit Orientation Technique (SMBBOT). SMBBOT consider the input plain text as binary bit stream. During encryption this stream is chopped into manageable sized blocks with variable lengths. Bits of these blocks are taken from MSB to LSB to fit into a square matrix of suitable order following the concept of Spiral matrix. This square matrix splits into 2x2 sub-matrices. Bits are taken column-wise from all 2x2 sub-matrices to form the encrypted binary string. Cipher tex…
It has been established that quantum algorithms can solve several key cryptographic problems more efficiently than classical computers. As progress continues in the field of quantum computing it is important to understand the risks they pose to deployed cryptographic systems. Here we focus on one of these risks - quantum key-recovery attacks against ideal ciphers. Specifically, we seek to model the risk posed by an economically motivated quantum attacker who will choose to run a quantum key-recovery attack against an ideal cipher if the cost to recover the secret key is less than the value of …
Page Frame Cache (PFC) is a purely software cache, present in modern Linux based operating systems (OS), which stores the page frames that are recently being released by the processes running on a particular CPU. In this paper, we show that the page frame cache can be maliciously exploited by an adversary to steer the pages of a victim process to some pre-decided attacker-chosen locations in the memory. We practically demonstrate an end-to-end attack, ExplFrame, where an attacker having only user-level privilege is able to force a victim process's memory pages to vulnerable locations in DRAM a…
The field of lightweight cryptography has been gaining popularity as traditional cryptographic techniques are challenging to implement in resource-limited environments. This research paper presents an approach to utilizing the ESP32 microcontroller as a hardware platform to implement a lightweight cryptographic algorithm. Our approach employs KATAN32, the smallest block cipher of the KATAN family, with an 80-bit key and 32-bit blocks. The algorithm requires less computational power as it employs an 80 unsigned 64-bit integer key for encrypting and decrypting data. During encryption, a data arr…
In this paper, a multilayer perceptron guided key generation for encryption/decryption (MLPKG) has been proposed through recursive replacement using mutated character code generation for wireless communication of data/information. Multilayer perceptron transmitting systems at both ends accept an identical input vector, generate an output bit and the network are trained based on the output bit which is used to form a protected variable length secret-key. For each session, different hidden layer of multilayer neural network is selected randomly and weights or hidden units of this selected hidden…
Evidence of signatures associated with cryptographic modes of operation is established. Motivated by some analogies between cryptographic and dynamical systems, in particular with chaos theory, we propose an algorithm based on Lyapunov exponents of discrete dynamical systems to estimate the divergence among ciphertexts as the encryption algorithm is applied iteratively. The results allow to distinguish among six modes of operation, namely ECB, CBC, OFB, CFB, CTR and PCBC using DES, IDEA, TEA and XTEA block ciphers of 64 bits, as well as AES, RC6, Twofish, Seed, Serpent and Camellia block ciphe…
The control of the cryptography is more than ever a recurrent issue. As the current international regulation does not apply in the signatory countries, the concept of enforcing backdoors in encryption system is reborn with more strength. This paper deals with a particular class of stream cipher backdoors. This class, under a different form, has been widely used by the industry in the 80s and 90s in the context of the export control rules imposed by the US to the Western countries. We propose here a new system -- called BSEA-2, with a 128-bit secret key -- which is a seemingly minor modificatio…
We cast encryption via classical block ciphers in terms of operator spreading in a dual space of Pauli strings, a formulation which allows us to characterize classical ciphers by using tools well known in the analysis of quantum many-body systems. We connect plaintext and ciphertext attacks to out-of-time order correlators (OTOCs) and quantify the quality of ciphers using measures of delocalization in string space such as participation ratios and corresponding entropies obtained from the wave function amplitudes in string space. The saturation of the string-space information entropy is accompa…
S-Boxes are important security components of block ciphers. We provide theoretical results on necessary or sufficient criteria for an (invertible) 4-bit S-Box to be weakly APN. Thanks to a classification of 4-bit invertible S-Boxes achieved independently by De Canniére and Leander-Poschmann, we can strengthen our results with a computer-aided proof.
Today, Internet communication security has become more complex as technology becomes faster and more efficient, especially for resource-limited devices such as embedded devices, wireless sensors, and radio frequency identification (RFID) tags, and Internet of Things (IoT). Lightweight encryption algorithms provide security for these devices to protect data against intruders. But the limitation of using energy in lightweight block ciphers (LBCs) is one of the major challenges for ever-expanding IoT technologies. Also, these LBC are subject to Side-channel attacks, which are among the most cited…
Non-Archimedean analysis, T-functions, and cryptography
These are lecture notes of a 20-hour course at the International Summer School \emph{Mathematical Methods and Technologies in Computer Security} at Lomonosov Moscow State University, July 9--23, 2006. Loosely speaking, a $T$ -function is a map of $n$ -bit words into $n$ -bit words such that each $i$ -th bit of image depends only on low-order bits $0,..., i$ of the pre-image. For example, all arithmetic operations (addition, multiplication) are $T$ -functions, all bitwise logical operations ( $\XOR$ , $\AND$ , etc.) are $T$ -functions. Any composition of $T$ -functions is a $T$ -function as wel…
In this note, the Cosmic Microwave Background (CMB) Radiation is shown to be capable of functioning as a Random Bit Generator, and constitutes an effectively infinite supply of truly random one-time pad values of arbitrary length. It is further argued that the CMB power spectrum potentially conforms to the FIPS 140-2 standard. Additionally, its applicability to the generation of a (n x n) random key matrix for a Vernam cipher is established.
This paper introduces an SPA power attack on the 8-bit implementation of the Twofish block cipher. The attack is able to unequivocally recover the secret key even under substantial amounts of error. An initial algorithm is described using exhaustive search on error free data. An error resistant algorithm is later described. It employs several threshold preprocessing stages followed by a combined approach of least mean squares and an optimized Hamming mask search. Further analysis of 32 and 64-bit Twofish implementations reveals that they are similarly vulnerable to the described SPA attack.
In a basic related-key attack against a block cipher, the adversary has access to encryptions under keys that differ from the target key by bit-flips. In this short note we show that for a quantum adversary such attacks are quite powerful: if the secret key is (i) uniquely determined by a small number of plaintext-ciphertext pairs, (ii) the block cipher can be evaluated efficiently, and (iii) a superposition of related keys can be queried, then the key can be extracted efficiently.
In this paper, we propose a novel fault attack termed as Single Event Transient Fault Analysis (SETFA) attack, which is well suited for hardware implementations. The proposed approach pinpoints hotspots in the cypher's Sbox combinational logic circuit that significantly reduce the key entropy when subjected to faults. ELEPHANT is a parallel authenticated encryption and associated data (AEAD) scheme targeted to hardware implementations, a finalist in the Lightweight cryptography (LWC) competition launched by NIST. In this work, we investigate vulnerabilities of ELEPHANT against fault analysis. …
One of the major open problems in symmetric cryptanalysis is to discover new specif i c types of invariant properties which can hold for a larger number of rounds of a block cipher. We have Generalised Linear Cryptanalysis (GLC) and Partitioning Cryptanalysis (PC). Due to double-exponential combinatorial explosion of the number of possible invariant properties systematic exploration is not possible and extremely few positive working examples of GLC are known. Our answer is to work with polynomial algebraic invariants which makes partitions more intelligible. We have developed a constructive al…
This paper gives the definition and property of a bit-pair shadow, and devises the three algorithms of a public key cryptoscheme called JUOAN that is based on a multivariate permutation problem and an anomalous subset product problem to which no subexponential time solutions are found so far, and regards a bit-pair as a manipulation unit. The authors demonstrate that the decryption algorithm is correct, deduce the probability that a plaintext solution is nonunique is nearly zero, analyze the security of the new cryptoscheme against extracting a private key from a public key and recovering a pl…
In this paper, we introduce a symmetric-key Latin square image cipher (LSIC) for grayscale and color images. Our contributions to the image encryption community include 1) we develop new Latin square image encryption primitives including Latin Square Whitening, Latin Square S-box and Latin Square P-box ; 2) we provide a new way of integrating probabilistic encryption in image encryption by embedding random noise in the least significant image bit-plane; and 3) we construct LSIC with these Latin square image encryption primitives all on one keyed Latin square in a new loom-like substitution-per…
Due to implementation constraints the XOR operation is widely used in order to combine plaintext and key bit-strings in secret-key block ciphers. This choice directly induces the classical version of the differential attack by the use of XOR-kind differences. While very natural, there are many alternatives to the XOR. Each of them inducing a new form for its corresponding differential attack (using the appropriate notion of difference) and therefore block-ciphers need to use S-boxes that are resistant against these nonstandard differential cryptanalysis. In this contribution we study the funct…
