In this work, we present various hardware implementations for the lightweight cipher ASCON, which was recently selected as the winner of the NIST organized Lightweight Cryptography (LWC) competition. We cover encryption + tag generation and decryption + tag verification for the ASCON AEAD and also the ASCON hash function. On top of the usual (unprotected) implementation, we present side-channel protection (threshold countermeasure) and triplication/majority-based fault protection. To the...

Authenticated Encryption with Associated Data (AEAD) is a trend in applied cryptography because it combine confidentiality, integrity, and authentication into one algorithm and is more efficient than using block ciphers and hash functions separately. The Ascon algorithm, as the winner in both the CAESAR competition and the NIST LwC competition, will soon become the AEAD standard for protecting the Internet of Things and micro devices with limited computing resources. We propose a partial...

The selection of a Lightweight Cryptography (LWC) algorithm is crucial for resource limited applications. The National Institute of Standards and Technology (NIST) leads this process, which involves a thorough evaluation of the algorithms’ cryptanalytic strength. Furthermore, careful consideration is given to factors such as algorithm latency, code size, and hardware implementation area. These factors are critical in determining the overall performance of cryptographic solutions at edge...

Higher order differential properties constitute a very insightful tool at the hands of a cryptanalyst allowing for probing a cryptographic primitive from an algebraic perspective. In FSE 2017, Saha et al. reported SymSum (referred to as SymSum_Vec in this paper), a new distinguisher based on higher order vectorial Boolean derivatives of SHA-3, constituting one of the best distinguishers on the latest cryptographic hash standard. SymSum_Vec exploits the difference in the algebraic degree...

This work investigates the security of the Ascon authenticated encryption scheme in the context of fault attacks, with a specific focus on Differential Fault Analysis (DFA). Motivated by the growing significance of lightweight cryptographic solutions, particularly Ascon, we explore potential vulnerabilities in its design using DFA. By employing a novel approach that combines faulty forgery in the decryption query under two distinct fault models, leveraging bit-flip faults in the first phase...

The cube attack is a powerful cryptanalysis technique against symmetric ciphers, especially stream ciphers. The adversary aims to recover secret key bits by solving equations that involve the key. To simplify the equations, a set of plaintexts called a cube is summed up together. Traditional cube attacks use only linear or quadratic superpolies, and the size of cube is limited to an experimental range, typically around 40. However, cube attack based on division property, proposed by Todo et...

Committing security has gained considerable attention in the field of authenticated encryption (AE). This can be traced back to a line of recent attacks, which entail that AE schemes used in practice should not only provide confidentiality and authenticity, but also committing security. Roughly speaking, a committing AE scheme guarantees that ciphertexts will decrypt only for one key. Despite the recent research effort in this area, the finalists of the NIST lightweight cryptography...

In this paper we introduce a new keyed hash function based on 32-bit integer multiplication that we call Multimixer-128. In our approach, we follow the key-then-hash parallel paradigm. So, we first add a variable length input message to a secret key and split the result into blocks. A fixed length public function based on integer multiplication is then applied on each block and their results are added to form the digest. We prove an upper bound of $2^{-127}$ for the universality of...

The Ascon authenticated encryption scheme has recently been selected as winner of the NIST Lightweight Cryptography competition. Despite its fame, however, there is no known overall generic security treatment of its mode: most importantly, all earlier related generic security results only use the key to initialize the state and do not take into account key blinding internally and at the end. In this work we present a thorough security analysis of the Ascon mode: we consider multi-user and...

The current work makes a systematic attempt to describe the effect of the relative order of round constant ( RCon) addition in the round function of an SPN cipher on its algebraic structure. The observations are applied to the SymSum distinguisher, introduced by Saha et al. in FSE 2017 which is one of the best distinguishers on the SHA3 hash function reported in literature. Results show that certain ordering (referred to as Type-LCN) of RCon makes the distinguisher less effective but it...

The Ascon cipher suite, offering both authenticated encryption with associated data (AEAD) and hashing functionality, has recently emerged as the winner of the NIST Lightweight Cryptography (LwC) standardization process. The AEAD schemes within Ascon, namely Ascon-128 and Ascon-128a, have also been previously selected as the preferred lightweight authenticated encryption solutions in the CAESAR competition. In this paper, we present a tight and comprehensive security analysis of the Ascon...

Side-channel resistance is one of the primary criteria identified by NIST for use in evaluating candidates in the Lightweight Cryptography (LWC) Standardization process. In Rounds 1 and 2 of this process, when the number of candidates was still substantial (56 and 32, respectively), evaluating this feature was close to impossible. With ten finalists remaining, side-channel resistance and its effect on the performance and cost of practical implementations became of utmost importance. In this...

The NIST LightWeight Cryptography (LWC) selection process aims to standardise cryptographic functionality which is suitable for resource-constrained devices. Since the outcome is likely to have significant, long-lived impact, careful evaluation of each submission with respect to metrics explicitly outlined in the call is imperative. Beyond the robustness of submissions against cryptanalytic attack, metrics related to their implementation (e.g., execution latency and memory footprint) form an...

We investigate the security of the NIST Lightweight Crypto Competition’s Finalists against side-channel attacks. We start with a mode-level analysis that allows us to put forward three candidates (As- con, ISAP and Romulus-T) that stand out for their leakage properties and do not require a uniform protection of all their computations thanks to (expensive) implementation-level countermeasures. We then implement these finalists and evaluate their respective performances. Our results confirm...

This paper analyses the lightweight, sponge-based NAEAD mode $\textsf{ISAP}$, one of the finalists of the NIST Lightweight Cryptography (LWC) standardisation project, that achieves high-throughput with inherent protection against differential power analysis (DPA). We observe that $\textsf{ISAP}$ requires $256$-bit capacity in the authentication module to satisfy the NIST LWC security criteria. In this paper, we study the analysis carefully and observe that this is primarily due to the...

The INT-RUP security of an authenticated encryption (AE) scheme is a well studied problem which deals with the integrity security of an AE scheme in the setting of releasing unverified plaintext model. Popular INT-RUP secure constructions either require a large state (e.g. GCM-RUP, LOCUS, Oribatida) or employ a two-pass mode (e.g. MON- DAE) that does not allow on-the-fly data processing. This motivates us to turn our attention to feedback type AE constructions that allow small state...

This paper presents results of performance evaluation of NIST Lightweight Cryptography standardization finalists which are implemented by us. Our implementation method puts on the target to reduce RAM consumption on embedded devices. Our target microcontrollers are AVR ATmega 128 and ARM Cortex-M3. We apply our implementation method to five AEAD schemes which include four finalists of the NIST lightweight cryptography standardization and demonstrate the performance evaluation on target...

GIFT-COFB is a lightweight AEAD scheme and a submission to the ongoing NIST lightweight cryptography standardization process where it currently competes as a finalist. The construction processes 128-bit blocks with a key and nonce of the same size and has a small register footprint, only requiring a single additional 64-bit register. Be- sides the block cipher, the mode of operation uses a bit permutation and finite field multiplication with different constants. It is a well-known...

This paper reports new software implementation results for the Skinny-128 tweakable block ciphers on various SIMD architectures. More precisely, we introduce a decomposition of the 8-bit S-box into four 4-bit S-boxes in order to take advantage of vector permute instructions, leading to significant performance improvements over previous constant-time implementations. Since our approach is of particular interest when Skinny-128 is used in sequential modes of operation, we also report how it...

Ascon-128 and Ascon-80pq use 12-round Ascon permutation for initialization and finalization phases and 6-round Ascon permutation for processing associate data and message. In a nonce-misuse setting, we present a new partial-state-recovery conditional-cube attack on Ascon-128 and Ascon-80pq, where 192 bits out of 320-bit state are recovered. For our partial state-recovery attack, its required data complexity, \(D\), is about \(2^{44.8}\) and its required memory complexity, \(M\), is...

In this work, we present a hardware implementation of the lightweight Authenticated Encryption with Associated Data (AEAD) SpoC-128. Designed by AlTawy, Gong, He, Jha, Mandal, Nandi and Rohit; SpoC-128 was submitted to the Lightweight Cryptography (LWC) competition being organised by the National Institute of Standards and Technology (NIST) of the United States Department of Commerce. Our implementation follows the Application Programming Interface (API) specified by the cryptographic...

We study the provable security claims of two NIST Lightweight Cryptography (LwC) finalists, GIFT-COFB and Photon-Beetle, and present several attacks whose complexities contradict their claimed bounds in their final round specification documents. For GIFT-COFB, we show an attack using $q_e$ encryption queries and no decryption query to break privacy (IND-CPA). The success probability is $O(q_e/2^{n/2})$ for $n$-bit block while the claimed bound contains $O(q^2_e/2^{n})$. This positively...

This paper proposes a lightweight authenticated encryption (AE) scheme, called Light-OCB, which can be viewed as a lighter variant of the CAESAR winner OCB as well as a faster variant of the high profi le NIST LWC competition submission LOCUS-AEAD. Light-OCB is structurally similar to LOCUS-AEAD and uses a nonce-based derived key that provides optimal security, and short-tweak tweakable blockcipher (tBC) for efficient domain separation. Light-OCB improves over LOCUS-AEAD by reducing the...

We propose to adapt ”low-algebra” digital signature schemes SPHINCS+ and PICNIC, present in the NIST-PQC contest, to the limitations of resource-bounded low-end devices. For this, we replaced the cryptographic primitives (hash functions and symmetric ciphers) of these schemes with lightweight alternatives presented in the NIST-LWC contest. With these specifically conceived primitives, we improve the performance of the signature schemes and still preserve the NIST’s security levels. Regarding...

Lightweight cryptography has recently gained importance as the number of Internet of things (IoT) devices connected to Internet grows. Its main goal is to provide cryptographic algorithms that can be run efficiently in resource-limited environments such as IoT. To meet the challenge, the National Institute of Standards and Technology (NIST) announced the Lightweight Cryptography (LWC) project. One of the finalists of the project is the TinyJAMBU cipher. This work evaluates the security of...

Automated methods have become crucial components when searching for distinguishers against symmetric-key cryptographic primitives. While MILP and SAT solvers are among the most popular tools to model ciphers and perform cryptanalysis, other methods with different performance profiles are appearing. In this article, we explore the use of Constraint Programming (CP) for differential cryptanalysis on the ASCON authenticated encryption family (first choice of the CAESAR lightweight applications...

FlexAEAD is a block cipher candidate submitted to the NIST Lightweight Cryptography standardization project, based on repeated application of an Even-Mansour construction. In order to optimize performance, the designers chose a relatively small number of rounds, using properties of the mode and bounds on differential and linear characteristics to substantiate their security claims. Due to a forgery attack with complexity $2^{46}$, FlexAEAD was not selected to the second round of evaluation...

This report presents area, throughput, and energy results for synthesizing the NIST Lightweight Cryptography Round 2 candidates on five ASIC cell libraries using two different synthesis tool suites.

Physical security of NIST lightweight cryptography competition candidates is gaining importance as the standardization process progresses. Side-channel attacks (SCA) are a well-researched topic within the physical security of cryptographic implementations. It was shown that collisions in the intermediate values can be captured by side-channel measurements to reduce the complexity of the key retrieval to trivial numbers. In this paper, we target a specific bit permutation vulnerability in...

In this work we develop optimized software implementationsfor ForkAE, a second round candidate in the ongoing NIST lightweight cryptography standardization process. Moreover, we analyze the perfor-mance and efficiency of different ForkAE implementations on two em-bedded platforms: ARM Cortex-A9 and ARM Cortex-M0.First, we study portable ForkAE implementations. We apply a decryption optimization technique which allows us to accelerate decryption by up to 35%. Second, we go on to explore...

Twenty seven Round 2 candidates in the NIST Lightweight Cryptography (LWC) process have been implemented in hardware by groups from all over the world. All implementations compliant with the LWC Hardware API, proposed in 2019, have been submitted for hardware benchmarking to George Mason University’s LWC benchmarking team. The received submissions were first verified for correct functionality and compliance with the hardware API’s specification. Then, the execution times in clock cycles, as...

WAGE is a hardware-oriented authenticated cipher, which has the smallest (unprotected) hardware cost (for 128-bit security level) among the round 2 candidates of the NIST lightweight cryptography (LWC) competition. In this work, we analyze the security of WAGE against the correlation power analysis (CPA) on ARM Cortex-M4F microcontroller. Our attack detects the secret key leakage from power consumption for up to 12 (out of 111) rounds of the WAGE permutation and requires 10,000 power traces...

Cryptographic protections are ubiquitous in information technology, including the emerging Internet of Things (IoT). As a result of technology migration to a resource-challenged landscape and new threats to cryptographic security, governments and industry are exploring new cryptographic algorithms. While new standards will emerge, however, old standards will not disappear for the time being. It is therefore important to explore platforms where multiple cryptographic deployments can be...

The bit-sliding paper of Jean et al. (CHES 2017) showed that the smallest-size circuit for SPN based block ciphers such as AES, SKINNY and PRESENT can be achieved via bit-serial implementations. Their technique decreases the bit size of the datapath and naturally leads to a significant loss in latency (as well as the maximum throughput). Their designs complete a single round of the encryption in 168 (resp. 68) clock cycles for 128 (resp. 64) bit blocks. A follow-up work by Banik et al. (FSE...

The selection criteria for NIST's Lightweight Crypto Standardization (LWC) have been slowly shifting towards the lightweight efficiency of designs, given that a large number of candidates already establish their security claims on conservative, well-studied paradigms. The research community has accumulated a decent level of experience on authenticated encryption primitives, thanks mostly to the recently completed CAESAR competition, with the advent of the NIST LWC, the de facto focus is now...

The "Competition for Authenticated Encryption: Security, Applicability, and Robustness" (CAESAR) was the first cryptographic competition that required designers to use a mandatory hardware API for their implementations. Recently, a similar hardware API for the NIST Lightweight Cryptography (LWC) project was proposed. Both APIs feature an accompanying development package to help designers implementing the API. In this paper, we have an in-depth look on these packages. We analyze the features...

The sponge duplex is a popular mode of operation for constructing authenticated encryption schemes. In fact, one can assess the popularity of this mode from the fact that around $ 25 $ out of the $ 56 $ round 1 submissions to the ongoing NIST lightweight cryptography (LwC) standardization process are based on this mode. Among these, $14$ sponge-type constructions are selected for the second round consisting of $32$ submissions. In this paper, we generalize the duplexing interface of the...

In this paper, we propose a comprehensive framework for fair and efficient benchmarking of hardware implementations of lightweight cryptography (LWC). Our framework is centered around the hardware API (Application Programming Interface) for the implementations of lightweight authenticated ciphers, hash functions, and cores combining both functionalities. The major parts of our API include the minimum compliance criteria, interface, and communication protocol supported by the LWC core. The...

Achieving security in the Internet of Things (IoT) is challenging. The need for lightweight yet robust cryptographic solutions suitable for the IoT calls for improved design and implementation of constructs such as authenticated encryption with associated data (AEAD) which can ensure confidentiality, integrity, and authenticity of data in one algorithm. The U.S. National Institute of Standards and Technology (NIST) has embarked on a multi-year effort called the lightweight cryptography...

This paper gives a new generalized key-recovery model of related-key rectangle attacks on block ciphers with linear key schedules. The model is quite optimized and applicable to various block ciphers with linear key schedule. As a proof of work, we apply the new model to two very important block ciphers, i.e. SKINNY and GIFT, which are basic modules of many candidates of the Lightweight Cryptography (LWC) standardization project by NIST. For SKINNY, we reduce the complexity of the best...

Most NIST Post-Quantum Cryptography (PQC) candidate algorithms use symmetric primitives internally for various purposes such as ``seed expansion'' and CPA to CCA transforms. Such auxiliary symmetric operations constituted only a fraction of total execution time of traditional RSA and ECC algorithms, but with faster lattice algorithms the impact of symmetric algorithm characteristics can be very significant. A choice to use a specific PQC algorithm implies that its internal symmetric...

FlexAEAD is one of the round-1 candidates in the ongoing NIST Lightweight Cryptography standardization project. In this note, we show several forgery attacks on FlexAEAD with complexity less than the security bound given by the designers, such as a block reordering attack on full FlexAEAD-128 with estimated success probability about $2^{-54}$. Additionally, we show some trivial forgeries and point out domain separation issues.