51 research outputs found
Analyzing the Shuffling Side-Channel Countermeasure for Lattice-Based Signatures
Implementation security for lattice-based cryptography is still a vastly unexplored field. At CHES 2016, the very first side-channel attack on a lattice-based signature scheme was presented. Later, shuffling was proposed as an inexpensive means to protect the Gaussian sampling component against such attacks. However, the concrete effectiveness of this countermeasure has never been evaluated.
We change that by presenting an in-depth analysis of the shuffling countermeasure. Our analysis consists of two main parts. First, we perform a side-channel attack on a Gaussian sampler implementation. We combine templates with a recovery of data-dependent branches, which are inherent to samplers. We show that an adversary can realistically recover some samples with very high confidence.
Second, we present a new attack against the shuffling countermeasure in context of Gaussian sampling and lattice-based signatures. We do not attack the shuffling algorithm as such, but exploit differing distributions of certain variables.
We give a broad analysis of our attack by considering multiple modeled SCA adversaries.
We show that a simple version of shuffling is not an effective countermeasure. With our attack, a profiled SCA adversary can recover the key by observing only 7000 signatures. A second version of this countermeasure, which uses Gaussian convolution in conjunction with shuffling twice, can increase side-channel security and the number of required signatures significantly. Here, roughly 285000 observations are needed for a successful attack. Yet, this number is still practical
Algorithmic Security is Insufficient: A Comprehensive Survey on Implementation Attacks Haunting Post-Quantum Security
This survey is on forward-looking, emerging security concerns in post-quantum
era, i.e., the implementation attacks for 2022 winners of NIST post-quantum
cryptography (PQC) competition and thus the visions, insights, and discussions
can be used as a step forward towards scrutinizing the new standards for
applications ranging from Metaverse, Web 3.0 to deeply-embedded systems. The
rapid advances in quantum computing have brought immense opportunities for
scientific discovery and technological progress; however, it poses a major risk
to today's security since advanced quantum computers are believed to break all
traditional public-key cryptographic algorithms. This has led to active
research on PQC algorithms that are believed to be secure against classical and
powerful quantum computers. However, algorithmic security is unfortunately
insufficient, and many cryptographic algorithms are vulnerable to side-channel
attacks (SCA), where an attacker passively or actively gets side-channel data
to compromise the security properties that are assumed to be safe
theoretically. In this survey, we explore such imminent threats and their
countermeasures with respect to PQC. We provide the respective, latest
advancements in PQC research, as well as assessments and providing visions on
the different types of SCAs
A Statistical Verification Method of Random Permutations for Hiding Countermeasure Against Side-Channel Attacks
As NIST is putting the final touches on the standardization of PQC (Post
Quantum Cryptography) public key algorithms, it is a racing certainty that
peskier cryptographic attacks undeterred by those new PQC algorithms will
surface. Such a trend in turn will prompt more follow-up studies of attacks and
countermeasures. As things stand, from the attackers' perspective, one viable
form of attack that can be implemented thereupon is the so-called "side-channel
attack". Two best-known countermeasures heralded to be durable against
side-channel attacks are: "masking" and "hiding". In that dichotomous picture,
of particular note are successful single-trace attacks on some of the NIST's
PQC then-candidates, which worked to the detriment of the former: "masking". In
this paper, we cast an eye over the latter: "hiding". Hiding proves to be
durable against both side-channel attacks and another equally robust type of
attacks called "fault injection attacks", and hence is deemed an auspicious
countermeasure to be implemented. Mathematically, the hiding method is
fundamentally based on random permutations. There has been a cornucopia of
studies on generating random permutations. However, those are not tied to
implementation of the hiding method. In this paper, we propose a reliable and
efficient verification of permutation implementation, through employing
Fisher-Yates' shuffling method. We introduce the concept of an n-th order
permutation and explain how it can be used to verify that our implementation is
more efficient than its previous-gen counterparts for hiding countermeasures.Comment: 29 pages, 6 figure
To BLISS-B or not to be - Attacking strongSwan’s implementation of post-quantum signatures
Session I1: Post-QuantumIn the search for post-quantum secure alternatives to RSA and ECC, lattice-based cryptography appears to be an attractive and efficient option. A particularly interesting lattice-based signature scheme is BLISS, offering key and signature sizes in the range of RSA moduli. A range of works on efficient implementations of BLISS is available, and the scheme has seen a first real-world adoption in strongSwan, an IPsec-based VPN suite. In contrast, the implementation-security aspects of BLISS, and lattice-based cryptography in general, are still largely unexplored. At CHES 2016, Groot Bruinderink et al. presented the first side-channel attack on BLISS, thus proving that this topic cannot be neglected. Nevertheless, their attack has some limitations. First, the technique is demonstrated via a proof-of-concept experiment that was not performed under realistic attack settings. Furthermore, the attack does not apply to BLISS-B, an improved variant of BLISS and also the default option in strongSwan. This problem also applies to later works on implementation security of BLISS. In this work, we solve both of the above problems. We present a new side-channel key-recovery algorithm against both the original BLISS and the BLISS-B variant. Our key-recovery algorithm draws on a wide array of techniques, including learning-parity with noise, integer programs, maximimum likelihood tests, and a lattice-basis reduction. With each application of a technique, we reveal additional information on the secret key culminating in a complete key recovery. Finally, we show that cache attacks on post-quantum cryptography are not only possible, but also practical. We mount an asynchronous cache attack on the production-grade BLISS-B implementation of strongSwan. The attack recovers the secret signing key after observing roughly 6000 signature generations.Peter Pessl, Leon Groot Bruinderink, Yuval Yaro
Arithmetic coding and blinding countermeasures for lattice signatures
We describe new arithmetic coding techniques and side-channel blinding countermeasures for lattice-based cryptography. Using these techniques, we develop a practical, compact, and more quantum-resistant variant of the BLISS Ideal Lattice Signature Scheme. We first show how the BLISS parameters and hash-based random oracle can be modified to be more secure against quantum pre-image attacks while optimizing signature size. Arithmetic Coding offers an information theoretically optimal compression for stationary and memoryless sources, such as the discrete Gaussian distributions often present in lattice-based cryptography. We show that this technique gives better signature sizes than the previously proposed advanced Huffman-based signature compressors. We further demonstrate that arithmetic decoding from an uniform source to target distribution is also an optimal non-uniform sampling method in the sense that a minimal amount of true random bits is required. Performance of this new Binary Arithmetic Coding sampler is comparable to other practical samplers. The same code tables, or circuitry can be utilized for both tasks, eliminating the need for separate sampling and compression components. We then describe simple randomized blinding techniques that can be applied to anti-cyclic polynomial multiplication to mask timing- and power consumption side-channels in ring arithmetic. We further show that the Gaussian sampling process can also be blinded by a split-and-permute techniques as an effective countermeasure against side-channel attacks
A practical key-recovery attack on LWE-based key-encapsulation mechanism schemes using Rowhammer
Physical attacks are serious threats to cryptosystems deployed in the real
world. In this work, we propose a microarchitectural end-to-end attack
methodology on generic lattice-based post-quantum key encapsulation mechanisms
to recover the long-term secret key. Our attack targets a critical component of
a Fujisaki-Okamoto transform that is used in the construction of almost all
lattice-based key encapsulation mechanisms. We demonstrate our attack model on
practical schemes such as Kyber and Saber by using Rowhammer. We show that our
attack is highly practical and imposes little preconditions on the attacker to
succeed. As an additional contribution, we propose an improved version of the
plaintext checking oracle, which is used by almost all physical attack
strategies on lattice-based key-encapsulation mechanisms. Our improvement
reduces the number of queries to the plaintext checking oracle by as much as
for Saber and approximately for Kyber768. This can be of
independent interest and can also be used to reduce the complexity of other
attacks
Side-channel Assisted Existential Forgery Attack on Dilithium - A NIST PQC candidate
The recent lattice-based signature scheme Dilithium, submitted as part of the CRYSTALS (Cryptographic Suite for Algebraic Lattices) package, is one of a number of strong candidates submitted for the NIST standardisation process of post-quantum cryptography. The Dilithium signature scheme is based on the Fiat-Shamir paradigm and can be seen as a variant of the Bai-Galbraith scheme (BG) combined with several improvements from previous ancestor lattice-based schemes like GLP and BLISS signature schemes. One of the main features of Dilithium is the compressed public-key, which is a rounded version of the LWE instance. This implies that Dilithium is not breakable with the knowledge of only the secret or the error of the LWE instance, unlike its ancestor lattice-based signature schemes. In this paper, we investigate the security of Dilithium against a combination of side-channel and classical attacks. Side-channel attacks on schoolbook and optimised polynomial multiplication algorithms in the signing procedure are shown to extract the secret component of the LWE instance, which is just one among the multiple components of the secret-key of Dilithium. We then propose an alternative signing procedure, through which it is possible to forge signatures with only the extracted portion of the secret-key, without requiring the knowledge of all its elements. Thus showing that Dilithium too breaks on just knowing the secret portion of the LWE instance, similar to previous lattice-based schemes
Implementation Attacks on Post-Quantum Cryptographic Schemes
Post-quantum cryptographic schemes have been developed in the last decade in response to the rise of quantum computers. Fortunately, several schemes have been developed with quantum resistance. However, there is very little effort in evaluating and comparing these schemes in the embedded settings. Low cost embedded devices represents a highly-constraint environment that challenges all post-quantum cryptographic schemes. Moreover, there are even fewer efforts in evaluating the security of these schemes against implementation attacks including side-channel and fault attacks. It is commonly accepted that, any embedded cryptographic module that is built without a sound countermeasure, can be easily broken. Therefore, we investigate the question: Are we ready to implement post-quantum cryptographic schemes on embedded systems? We present an exhaustive survey of research efforts in designing embedded modules of post-quantum cryptographic schemes and the efforts in securing these modules against implementation attacks. Unfortunately, the study shows that: we are not ready yet to implement any post-quantum cryptographic scheme in practical embedded systems. There is still a considerable amount of research that needs to be conducted before reaching a satisfactory level of security
Separating Oil and Vinegar with a Single Trace
Due to recent cryptanalytical breakthroughs, the multivariate signature schemes that seemed to be most promising in the past years are no longer in the focus of the research community. Hence, the cryptographically mature UOV scheme is of great interest again. Since it has not been part of the NIST process for standardizing post-quantum cryptography so far, it has not been studied intensively for its physical security.
In this work, we present a side-channel attack on the latest implementation of UOV. In the first part of the attack, a single side-channel trace of the signing process is used to learn all vinegar variables used in the computation. Then, we employ a combination of the Kipnis-Shamir attack and the reconciliation attack to reveal the complete secret key. Our attack, unlike previous work, targets the inversion of the central map and not the subsequent linear transformation. It further does not require the attacker to control the message to be signed.
We have verified the practicality of our attack on a ChipWhisperer-Lite board with a 32-bit STM32F3 ARM Cortex-M4 target mounted on a CW308 UFO board. We publicly provide the code and both reference and target traces. Additionally, we discuss several countermeasures that can at least make our attack less efficient
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