Machine learning (ML) has been widely deployed in various applications, with many applications being in critical infrastructures. One recent paradigm is edge ML, an implementation of ML on embedded devices for Internet-of- Things (IoT) applications. In this work, we have conducted a practical experiment on Intel Neural Compute Stick (NCS) 2, an edge ML device, with regard to fault injection (FI) attacks. More precisely, we have employed electromagnetic fault injection (EMFI) on NCS 2 to evaluate the practicality of the attack on a real target device. We have investigated multiple fault parameters with a low-cost pulse generator, aiming to achieve misclassification at the output of the inference. Our experimental results demonstrated the possibility of achieving practical and repeatable misclassifications.

Formal verification is widely used for checking the correctness of a system with respect to the succinct properties at early design phase. In recent times, these methods are also adopted to validate the security of a system by rightly abstracting the security-oriented properties. In this work, we focus on a recently reported attack on the secure boot process of Zynq-7000 platform. We study the vulnerability with formal analysis of its boot loader code. The challenge is to model the system and identify the right set of properties so that, the vulnerability is exposed quickly. It is shown that the UPPAAL model checking analysis can be used, which helps to find the vulnerability instantaneously with the help of four properties and a virtual memory usage peak of about 50MB to test each property. To the best of our knowledge, we perform the first analysis of UPPAAL on a concrete software implementation and perform a case study on a real security vulnerability reported in a CVE [1].

Post-quantum Cryptography (PQC) has reached the verge of standardization competition, with Kyber as a winning candidate. In this work, we demonstrate practical backdoor insertion in Kyber through kleptrography. The backdoor can be inserted using classical techniques like ECDH or post-quantum Classic Mceliece. The inserted backdoor targets the key generation procedure where generated output public keys subliminally leak information about the secret key to the owner of the backdoor. We demonstrate first practical instantiations of such attack at the protocol level by validating it on TLS 1.3.

In this work, we present a systematic study of Side-Channel Attacks (SCA) and Fault Injection Attacks (FIA) on structured lattice-based schemes, with main focus on Kyber Key Encapsulation Mechanism (KEM) and Dilithium signature scheme, which are leading candidates in the NIST standardization process for Post-Quantum Cryptography (PQC). Through our study, we attempt to understand the underlying similarities and differences between the existing attacks while classifying them into different categories. Given the wide variety of reported attacks, simultaneous protection against all the attacks requires to implement customized protections/countermeasures for both Kyber and Dilithium. We therefore present a range of customized countermeasures, capable of providing defenses/mitigations against existing SCA/FIA, and incorporate several SCA and FIA countermeasures within a single design of Kyber and Dilithium. Among the several countermeasures discussed in this work, we present novel countermeasures that offer simultaneous protection against several SCA- and FIA-based chosen-ciphertext attacks for Kyber KEM. We implement the presented countermeasures within two well-known public software libraries for PQC: (1) pqm4 library for the ARM Cortex-M4-based microcontroller and (2) liboqs library for the Raspberry Pi 3 Model B Plus based on the ARM Cortex-A53 processor. Our performance evaluation reveals that the presented custom countermeasures incur reasonable performance overheads on both the evaluated embedded platforms. We therefore believe our work argues for usage of custom countermeasures within real-world implementations of lattice-based schemes, either in a standalone manner or as reinforcements to generic countermeasures such as masking.

Recent work has shown that Side-Channel Attacks (SCA) and Fault Attacks (FA) can be combined, forming an extremely powerful adversarial model, which can bypass even some strongest protections against both FA and SCA. However, such strongest form of combined attack comes with some practical challenges - 1) a profiled setting with multiple fault locations is needed; 2) fault models are restricted to single-bit set-reset/flips; 3) the input needs to be repeated several times. In this paper, we propose a new combined attack strategy called SCA-NFA that works in a non-profiled setting. Assuming knowledge of plaintexts/ciphertexts and exploiting bitsliced implementations of modern ciphers, we further relax the assumptions on the fault model, and the number of fault locations - random multi-bit fault at a single fault location is sufficient for recovering several secret bits. Furthermore, the inputs are allowed to be varied, which is required in several practical use cases. The attack is validated on a recently proposed countermeasure called DOMREP, which individually provides SCA and FA protection of arbitrary order. Practical validation for an open-source masked implementation of GIMLI with DOMREP extension on STM32F407G, using electromagnetic fault and electromagnetic SCA, shows that SCA- NFA succeeds in around 10000 measurements.

Kyber KEM, the NIST selected PQC standard for Public Key Encryption and Key Encapsulation Mechanisms (KEMs) has been subjected to a variety of side-channel attacks, through the course of the NIST PQC standardization process. However, all these attacks targeting the decapsulation procedure of Kyber KEM either require knowledge of the ciphertexts or require to control the value of ciphertexts for key recovery. However, there are no known attacks in a blind setting, where the attacker does not have access to the ciphertexts. While blind side-channel attacks are known for symmetric key cryptographic schemes, we are not aware of such attacks for Kyber KEM. In this paper, we fill this gap by proposing the first blind side-channel attack on Kyber KEM. We target leakage of the pointwise multiplication operation in the decryption procedure to carry out practical blind side-channel attacks resulting in full key recovery. We perform practical validation of our attack using power side-channel from the reference implementation of Kyber KEM taken from the pqm4 library, implemented on the ARM Cortex-M4 microcontroller. Our experiments clearly indicate the feasibility of our proposed attack in recovering the full key in only a few hundred to few thousand traces, in the presence of a suitably accurate Hamming Weight (HW) classifier.

In this work, we propose generic and practical side-channel attacks for message recovery in post-quantum lattice-based public key encryption (PKE) and key encapsulation mechanisms (KEM). The targeted schemes are based on the well known Learning With Errors (LWE) and Learning With Rounding (LWR) problem and include three finalists and six semi-finalist candidates of the ongoing NIST’s standardization process for post-quantum cryptography. Notably, we propose to exploit inherentciphertext malleabilityproperties of LWE/LWR-based PKEs as a powerful tool for side-channel assisted message recovery attacks. The use of ciphertext malleability widens the scope of previous attacks with the ability to target multiple operations for message recovery. Moreover, our attacks are adaptable to different implementation variants and are also applicable to implementations protected with concreteshufflingandmaskingside-channel countermeasures. Our work mainly highlights the presence of inherent algorithmic properties in LWE/LWR-based schemes that can aid side-channel attacks for message recovery, thereby stressing on the need for strong side-channel countermeasures against message recovery for LWE/LWR-based schemes.

The impending threat of large-scale quantum computers to classical RSA and ECC-based public-key cryptographic schemes prompted NIST to initiate a global level standardization process for post-quantum cryptography. This process which started in 2017 with 69 submissions is currently in its third and final round with seven main candidates and eight alternate candidates, out of which seven (7) out of the fifteen (15) candidates are schemes based on hard problems over structured lattices, known as lattice-based cryptographic schemes. Among the various parameters such as theoretical post-quantum (PQ) security guarantees, implementation cost and performance, resistance against physical attacks such as Side-Channel Analysis (SCA) and Fault Injection Analysis (FIA) has also emerged as an important criterion for standardization in the final round [1]. This is especially relevant for adoption of PQC in embedded devices, which are most likely used in environments where an attacker can have unimpeded physical access to the device.

Ensuring communication security in real-time automotive networks is of paramount importance given the sensitivity of the exchanged information and highly safety critical nature of its operation. The first step towards ensuring security is to securely authenticate all the computational nodes through use of authentication protocols based on public-key cryptography. But, traditional public-key cryptographic primitives we use today are believed to be breakable by large scale quantum computers of the future. Thus, NIST is currently running a global global level standardization process for quantum-resistant public-key cryptography, better known as post-quantum cryptography. In this work, we perform a first of its kind practical implementation of a secure authentication protocol for automotive systems with post-quantum cryptographic algorithms and perform a detailed comparative evaluation of the speed and communication bandwidth performance against their pre-quantum counterparts.

In this paper, we analyze the implementation level fault vulnerabilities of deterministic lattice-based signature schemes. In particular, we extend the practicality of skip-addition fault attacks through exploitation of determinism in Dilithium and qTESLA signature schemes, which are two leading candidates for the NIST standardization of post-quantum cryptography. We show that single targeted faults injected in the signing procedure allow to recover an important portion of the secret key. Though faults injected in the signing procedure do not recover all the secret key elements, we propose a novel forgery algorithm that allows the attacker to sign any given message with only the extracted portion of the secret key. We perform experimental validation of our attack using Electromagnetic fault injection on reference implementations taken from the pqm4 library, a benchmarking and testing framework for post quantum cryptographic implementations for the ARM Cortex-M4 microcontroller. We also show that our attacks break two well known countermeasures known to protect against skip-addition fault attacks. We further propose an efficient mitigation strategy against our attack that exponentially increases the attacker's complexity at almost zero increase in computational complexity.

We present RunStream, a rapid prototyping framework for realizing stream cipher implementations based on algorithmic specifications and architectural customizations desired by the users. In the dynamic world of cryptography where newer recommendations are frequently proposed, the need of such tools is imperative. It carries out design validation and generates an optimized software implementation and a synthesizable Register Transfer Level Verilog description. Our framework enables speedy benchmarking against critical resources like area, throughput, power, and latency and allows exploration of alternatives. Using RunStream, we successfully implemented various stream ciphers and benchmarked the quality of results to be at par with published hand-optimized implementations.