Willy Susilo

Willy Susilo
University of Wollongong | UOW · School of Computing and Information Technology (SCIT)

PhD

About

815
Publications
136,037
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17,598
Citations
Citations since 2017
311 Research Items
10711 Citations
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201720182019202020212022202305001,0001,5002,000
Additional affiliations
December 2001 - present
University of Wollongong
Position
  • Professor (Full)

Publications

Publications (815)
Chapter
Recently, we have witnessed an upward trend in adopting the Transport Layer Security version 1.3 (TLS 1.3) to numerous applications (Google Cloud [25], Microsoft software products [20], CloudFlare [27]). Although TLS 1.3 provides higher efficiency than the previous versions of TLS, its handshake protocol still requires the server to send its certif...
Article
Full-text available
The popularity of the Metaverse has rapidly increased in recent years. However, despite the attention, investment, and promise of the Metaverse, there are various cybersecurity issues that must be addressed before the Metaverse can truly be adopted in practice for serious applications. The realization of the Metaverse is envisioned by many as requi...
Article
In a traditional health system, it merely depends on doctors’ initiative reports to discover infectious diseases, which causes late responses from the Center for Disease Control (CDC) and therefore may result in snowballed loss of lives and economy. Sometimes, the disease has spread when doctors realize it is infectious, and the CDC has to invest m...
Chapter
Range proofs introduced by Brickell et al. at CRYPTO 1988, allow a prover to convince a verifier that the committed value belongs to an interval without revealing anything else. It has become an essential building block in various modern cryptographic protocols such as distributed ledgers, anonymous transactions, e-cash, e-voting, auction protocols...
Chapter
Trojan attacks on deep neural networks are both dangerous and surreptitious. Over the past few years, Trojan attacks have advanced from using only a single input-agnostic trigger and targeting only one class to using multiple, input-specific triggers and targeting multiple classes. However, Trojan defenses have not caught up with this development....
Article
Crowdsensing is an emerging data collection paradigm that enables data collected from a large number of Internet of Things devices to support effective decision-making. Anomaly counting as a data analysis method allows the identification of unintended behaviors to enhance decision-making capabilities. However, ensuring the sensing data privacy and...
Chapter
We introduce Multimodal Private Signature (MPS) - an anonymous signature system that offers a novel accountability feature: it allows a designated opening authority to learn some partial information \(\textsf{op}\) about the signer’s identity \(\textsf{id}\), and nothing beyond. Such partial information can flexibly be defined as \(\textsf{op} = \t...
Chapter
A software watermarking scheme can embed a message into a program while preserving its functionality. The embedded message can be extracted later by an extraction algorithm, and no one could remove it without significantly changing the functionality of the program. A watermarking scheme is public key if neither the marking procedure nor the extract...
Chapter
The Multi-Prime Power RSA is an efficient variant of the RSA cryptosystem with a modulus of the form \(N=p^rq^s\) and \(r>s\ge 2\). It can be used with a public exponent e and a private exponent d satisfying \(e\equiv \frac{1}{d}\pmod {p^{r-1}q^{s-1}(p-1)(q-1)}\). In 2017, Lu, Peng and Sarkar showed that one can factor the modulus \(N=p^rq^s\) if \...
Chapter
In the automatic speech recognition (ASR) domain, most, if not all, current audio AEs are generated by applying perturbations to input audio. Adversaries either constrain norm of the perturbations or hide perturbations below the hearing threshold based on psychoacoustics. These two approaches have their respective problems: norm-constrained perturb...
Chapter
Spatial encryption (SE), which involves encryption and decryption with affine/vector objects, was introduced by Boneh and Hamburg at Asiacrypt 2008. Since its introduction, SE has been shown as a versatile and elegant tool for implementing many other important primitives such as (Hierarchical) Identity-based Encryption ((H)IBE), Broadcast (H)IBE, A...
Chapter
Unique ring signatures (URS) were introduced by Franklin and Zhang (FC 2012) as a unification of linkable and traceable ring signatures. In URS, each member within a ring can only produce, on behalf of the ring, at most one signature for a message.Applications of URS potentially are e–voting systems and e–token systems. In blockchain technology, UR...
Chapter
Public cloud data auditing allows any third party to check the integrity of data stored on untrusted cloud servers without retrieving the data. The challenge is how to audit the proof of storage with efficient communications. In ACM CCS 2007, Ateniese et al. described the first practical public cloud data auditing scheme based on RSA, in which the...
Chapter
Many practical secure systems have been designed to prevent real-world attacks via maximizing the attacking cost so as to reduce attack intentions. Inspired by this philosophy, we propose a new concept named delay encryption with keyword search (DEKS) to resist the notorious keyword guessing attack (KGA), in the context of secure cloud-based search...
Chapter
Puncturable signature (PS), proposed by Bellare, Stepanovs and Waters at EUROCRYPT 2016, is a special kind of digital signature that supports a fine-grained revocation of signing capacity by updating the secret key with selective messages. Puncturable signature has many usages like asynchronous transaction data signing services and proof-of-stake b...
Article
CCA security is desirable when designing encryption schemes because it captures active attackers. One efficient approach for achieving CCA security is to use generic conversions. We first design a CPA secure scheme, and then transform it into a CCA secure scheme using the Fujisaki-Okamoto technique (CRYPTO ’99) in the random oracle model or the Can...
Preprint
Full-text available
Adversarial attacks on deep learning-based models pose a significant threat to the current AI infrastructure. Among them, Trojan attacks are the hardest to defend against. In this paper, we first introduce a variation of the Badnet kind of attacks that introduces Trojan backdoors to multiple target classes and allows triggers to be placed anywhere...
Article
As a prominent cryptographic tool, geometric searchable encryption (GSE) can be applied in many scenarios, such as location-based services (LBS), social networks and vehicle networks. Unfortunately, most of existing searchable encryption schemes supporting the functionality of geometric range searches suffer from false positives, which will lead pe...
Article
Full-text available
In a designated verifier signature (DVS) scheme, a signer (Alice) generates a signature which can only be verified by a designated verifier (Bob) chosen by her. Moreover, Bob cannot transfer his conviction about Alice’s signature to any third party. A DVS scheme provides the capability of authenticating Alice to Bob without disrupting her privacy....
Article
The concept of puncturable encryption (PE) was introduced by Green and Miers at IEEE S&P, 2015. PE allows recipients to update their decryption keys to revoke decryption capability for selected messages without communicating with senders. From the first instantiation, PE shows its essence for many interesting applications, such as asynchronous mess...
Article
As cloud computing has developed rapidly, outsourcing data to cloud servers for remote storage has become an attractive trend. However, when cloud clients store their data in the cloud, the security and privacy of cloud data would be threatened due to accidental corruptions or purposive attacks caused by a semi-trusted cloud server. The widely used...
Preprint
Backdoor attacks have been a critical threat to deep neural network (DNN). However, most existing countermeasures focus on source-agnostic backdoor attacks (SABAs) and fail to defeat source-specific backdoor attacks (SSBAs). Compared to an SABA, an SSBA activates a backdoor when an input from attacker-chosen class(es) is stamped with an attacker-sp...
Chapter
Unique signatures are digital signatures with exactly one unique and valid signature for each message. The security reduction for most unique signatures has a natural reduction loss (in the existentially unforgeable against chosen-message attacks, namely EUF-CMA, security model under a non-interactive hardness assumption). In Crypto 2017, Guo et al...
Article
Group encryption (GE), the encryption analog of group signatures, is a fundamental primitive that offers a privacy-preserving service for a specific receiver concealed within a group of certified users. Like other cryptographic primitives, GE constructions are always considered relative to the potential danger of quantum computations. The only exis...
Chapter
In this paper, we propose a practical signature scheme based on the alternating trilinear form equivalence problem. Our scheme is inspired by the Goldreich-Micali-Wigderson’s zero-knowledge protocol for graph isomorphism, and can be served as an alternative candidate for the NIST’s post-quantum digital signatures. First, we present theoretical evid...
Article
Cloud storage becomes the priority for storing and sharing data for enterprise users. Encrypting prior to uploading data to the cloud is the best way to protect business secrets, however, it hinders the convenient operations on plaintexts, such as searching over the cloud data. In addition, employees in an enterprise have multiple layer structures...
Article
Full-text available
Adversaries may target alerting alarms raised by PLCs (Programmable Logic Controllers) to prevent notifying operators of critical conditions, to hide faults, to disrupt operations, to cause damages to ICS (Industrial Control Systems) and surrounding environment, or to lead to financial loss. The paper focuses on exposing vulnerabilities of the ladd...
Article
Full-text available
In recent years, the development of vehicular ad-hoc networks (VANETs) has received much attention in intelligent transportation systems (ITS). Unlike traditional ad-hoc networks, VANETs are emerging with unique characteristics that share similar technology with autonomous vehicles (AVs) and automated driving systems (ASDs). Communication between v...
Article
With the rapid development of secure multi-party computation (MPC) over past decades, applications of MPC has been moving from completing simple computation tasks (e.g., private set intersection) to complex computation tasks (e.g., privacy-preserving machine learning). This is an inevitable trend when more strict privacy protection requirements fac...
Article
In recent years, data generated by Internet of Things (IoT) devices has become increasingly massive. The amount of data stored in the cloud is also enormous and needs to be processed in a timely, efficient, secure, and private manner. While data stored on the cloud is guaranteed to be available, this does not mean that the secrecy and privacy of th...
Article
How to use efficient search mechanisms to realize data sharing while ensuring data security has become an important research topic at present. In this paper, we propose a new searchable algorithm based on LSSS (Linear Secret Sharing Scheme) access policy, which is superior to previous work in computational and storage efficiency. Our scheme support...
Preprint
Full-text available
Trojan attacks on deep neural networks are both dangerous and surreptitious. Over the past few years, Trojan attacks have advanced from using only a simple trigger and targeting only one class to using many sophisticated triggers and targeting multiple classes. However, Trojan defenses have not caught up with this development. Most defense methods...
Preprint
Full-text available
Cooperative learning, that enables two or more data owners to jointly train a model, has been widely adopted to solve the problem of insufficient training data in machine learning. Nowadays, there is an urgent need for institutions and organizations to train a model cooperatively while keeping each other's data privately. To address the issue of pr...
Article
Code reuse attacks (CRAs), such as return-oriented programming (ROP) and jump-oriented programming (JOP) attacks, have become a great threat to the runtime security of ARM-based Internet of Things (IoT) devices. Attackers can utilize CRAs to hijack the control flow of programs in ARM-based IoT devices to make them perform malicious actions without...
Chapter
Full-text available
Mobile devices commonly employ speech recognition (SR) techniques to facilitate user interaction. Typical voice assistants on mobile devices detect a wake word or phrase before allowing users to use voice commands. While the core functionality of contemporary SR systems relies on deep learning, researchers have shown that deep learning suffers from...
Article
monospace>NewHope Key Encapsulation Mechanism (KEM) has been presented at USENIX 2016 by Alkim et al. and was one of the lattice-based candidates to the post-quantum standardization initiated by the NIST. However, despite the relative simplicity of the protocol, the bound on the decapsulation failure probability resulting from the original analy...
Article
Cloud computing has become one of the most popular distributed computing paradigms in recent years. With its advantages of low cost, on-demand flexibility, and high data processing abilities, more and more enterprises have adopted the cloud computing paradigm to build up their IT infrastructure. By performing collaborative computation tasks (e.g.,...
Article
Attribute-based encryption scheme is a promising mechanism to realize one-to-many fine-grained access control which strengthens the security in cloud computing. However, massive amounts of data and various data sharing requirements bring great challenges to the complex but isolated and fixed access structures in most of the existing attribute-based...
Article
In the above article, Zhang et al. (2021) proposed a many-to-many authentication and key agreement scheme named SMAKA for secure authentication and key agreement between multiple vehicles and cloud service providers (CSPs) in a vehicular network. However, we identify a security flaw in the design of Zhang et al. ’s scheme, which allows an attac...
Article
Dynamic searchable symmetric encryption (DSSE) has been widely recognized as a promising technique to delegate update and search queries over an outsourced database to an untrusted server while guaranteeing the privacy of data. Many efforts on DSSE have been devoted to obtaining a good tradeoff between security and performance. However, it appe...
Article
The Internet of Things and cloud services have been widely adopted in many applications, and personal health records (PHR) can provide tailored medical care. The PHR data is usually stored on cloud servers for sharing. Weighted ABE is a practical and flexible technique to protect PHR data. Under a weighted ABE policy, the data user's attributes wil...
Article
Cloud storage service provides a convenient way for users to store massive data. To guarantee the integrity of the outsourced data, provable data possession (PDP) schemes for multi-copy data and multi-cloud have been proposed respectively. To avoid a single point of failure and to increase the security of the outsourced data, many users store multi...
Article
Collecting and analyzing patients' e-healthcare data in Medical Internet-of-Things (MIOT), e-Healthcare providers can offer reliable medical services that will achieve better treatment for patients. For example, the diagnosis of disease and predictions of health offer an alternative and helpful evaluation of the risk of diseases, thereby helping pa...
Article
To improve the quality of medical care and reduce unnecessary medical errors, electronic medical records (EMRs) are widely applied in hospital information systems. However, rapidly increasing EMRs bring heavy storage burden to hospitals. Professional data management service provided by cloud server can save the hospital local storage, and meanwhile...
Article
Cloud auditing enables the integrity verification of cloud data without the necessity of data retrieval, which significantly promotes the storage service of cloud computing. Auditing with ownership transfer is a variation where both cloud data and the tags for integrity verification can be transferred. In some scenarios, like joint-stock enterprise...
Article
The wide use of internet-connected services makes massive personal data collected by service providers without the need of our consent. Although the archived data may enable them to provide better service experiences for users, it also presents serious risks to individual privacy, especially when active or unexpected data breaches have become commo...
Article
Driven by various legal obligations and service requirements, the redactable blockchain was introduced to balance the modifiability and immutability of blockchain technology. However, such a blockchain inevitably generates one or even more acceptable versions for the same block data, enabling malicious full nodes to deceive light/new nodes with old...
Article
Full-text available
We propose a new functional encryption for pattern matching scheme with a hidden string. In functional encryption for pattern matching (FEPM), access to a message is controlled by its description and a private key that is used to evaluate the description for decryption. In particular, the description with which the ciphertext is associated is an ar...
Article
Functional signatures (FS) enable a master authority to delegate its signing privilege to an assistant. Concretely, the master authority uses its secret key skF to issue a signing key skf for a designated function \(f \in {{\cal F}_{{\rm{FS}}}}\) and sends both f and skf to the assistant \({\cal E}\), which is then able to compute a signature σf wi...
Chapter
Group encryption (GE) is a fundamental privacy-preserving primitive analog of group signatures, which allows users to decrypt specific ciphertexts while hiding themselves within a crowd. Since its first birth, numerous constructions have been proposed, among which the schemes separately constructed by Libert et al. (Asiacrypt 2016) over lattices an...
Article
Full-text available
Context The reengineering process of large data-intensive legacy software applications (“legacy applications” for brevity) to cloud platforms involves different interrelated activities. These activities are related to planning, architecture design, re-hosting/lift-shift, code refactoring, and other related ones. In this regard, the cloud computing...
Article
With the rapid growth of cloud storage and cloud computing services, many organisations and users choose to store the data on a cloud server for saving costs. However, due to security concerns, data of users would be encrypted before sending to the cloud. However, this hinders a problem of computation on encrypted data in the cloud, especially in t...
Article
Wildcard identity-based encryption (WIBE) is a generalization of hierarchical identity-based encryption (HIBE) where a sender can simultaneously encrypt messages to a group of users matching a certain pattern, defined as a sequence of identities and wildcards. This special feature makes WIBE a promising solution to distributed IoT data security. In...
Chapter
We consider four variants of the RSA cryptosystem with an RSA modulus \(N=pq\) where the public exponent e and the private exponent d satisfy an equation of the form \(ed-k\left( p^2-1\right) \left( q^2-1\right) =1\). We show that, if the prime numbers p and q share most significant bits, that is, if the prime difference \(|p-q|\) is sufficiently s...
Chapter
Full-text available
Automatic speech recognition (ASR) is an essential technology used in commercial products nowadays. However, the underlying deep learning models used in ASR systems are vulnerable to adversarial examples (AEs), which are generated by applying small or imperceptible perturbations to audio to fool these models. Recently, universal adversarial perturb...
Chapter
The concept of puncturable encryption was introduced by Green and Miers at IEEE S&P 2015. Puncturable encryption allows recipients to update their decryption keys to revoke decryption capability for selected messages without communicating with senders. From the first instantiation, puncturable encryption shows its essence for many interesting appli...
Chapter
Group encryption (GE) is a fundamental anonymity primitive analogue of group signature, which guarantees the decryption ability of recipients to specific ciphertexts while hiding these users within a crowd. Since its first birth by Kiayias et al., numerous constructions have been proposed, among which there is only one lattice-based scheme is post-...
Chapter
Full-text available
Automatic speech recognition (ASR) systems are now ubiquitous in many commonly used applications, as various commercial products rely on ASR techniques, which are increasingly based on machine learning, to transcribe voice commands into text for further processing. However, audio adversarial examples (AEs) have emerged as a serious security threat,...
Chapter
Vector commitment and its variants have attracted a lot of attention recently as they have been exposed to a wide range of applications in blockchain. Two special extensions of vector commitments, namely subvector commitments and mercurial commitments, have been proposed with attractive features that are desirable in many applications. Nevertheless...
Chapter
The emergence of public-key encryption with keyword search (PEKS) has provided an elegant approach to enable keyword search over encrypted content. Due to its high computational complexity proportional to the number of intended receivers, the trivial way of deploying PEKS for data sharing with multiple receivers is impractical, which motivates the...
Chapter
Blockchain is a distributed ledger in which a database is distributed across numerous users. Blockchain technologies have recently come to the forefront of the research and industrial communities as they bring potential benefits for many industries. A ring signature is a special type of digital signature which has been widely adopted to protect ano...
Chapter
There has been renewed attention to threshold signature in recent years as the threshold version of the ECDSA and SM2 Elliptic Curve Cryptographic Algorithm (SM2) could be used in Bitcoin as an underlying digital signature scheme to protect users’ private keys that guarantees transactions. A (t, n) threshold signature scheme means in a set of n par...
Chapter
In this paper, we propose a new searchable encryption with shiftable trapdoor (SEST) scheme to enable pattern matching over encrypted data. In the proposed scheme, data is encrypted per character and the trapdoor for searching can be shifted. This implies that the trapdoor can be created over any string, which is not necessarily pre-defined. Also,...
Chapter
As smart devices connected to networks like Internet of Things and 5G become popular, the volume of data generated over time (i.e., stream data) by them is growing rapidly. As a consequence, for these resources-limited client-side devices, it becomes very challenging to store the continuously generated stream data locally. Although the cloud storag...
Chapter
Proxy re-encryption (PRE), introduced by Blaze, Bleumer, and Strauss at EUROCRYPT 98, offers delegation of decryption rights, i.e., it securely enables the re-encryption of ciphertexts from one key to another, without relying on trusted parties. PRE allows a semi-trusted third party termed as a “proxy” to securely divert ciphertexts of a user (dele...
Chapter
Privacy preserving mechanisms are essential for protecting data in IoT environments. This is particularly challenging as IoT environments often contain heterogeneous resource-constrained devices. One method for protecting privacy is to encrypt data with a pattern or metadata. To prevent information leakage, an evaluation using the pattern must be p...
Chapter
Dynamic searchable symmetric-key encryption (DSSE) is a promising crypto-tool that enables secure keyword searching over dynamically added or deleted ciphertexts. Currently, many works on DSSE devote their efforts to obtaining forward and backward security and practical performance. However, it is still challenging to design a single DSSE scheme th...
Article
The explosive growth of the Internet of Things (IoT) devices is an inevitable trend, especially considering the fact that 5G technology facilitates numerous services building on IoT devices. IoT devices deliver great convenience to our daily lives; nevertheless, they are becoming attractive attacking targets. Compromised IoT devices can result in t...
Preprint
Full-text available
The reengineering process of large data-intensive legacy software applications to cloud platforms involves different interrelated activities. These activities are related to planning, architecture design, re-hosting/lift-shift, code refactoring, and other related ones. In this regard, the cloud computing literature has seen the emergence of differe...
Article
Data deduplication and public auditing are significant for providing secure and efficient network storage services. However, the existing data deduplication schemes supporting auditing not only cannot effectively alleviate the threats of the single point of failure and duplicate-faking attack, but also have to bear the massive waste of computation...
Article
Certificateless public key cryptography (CL-PKC) overcomes the difficulties of the certificate managements in traditional public key infrastructure (PKI) and the key escrow problem in ID-Based public key cryptography (ID-PKC), concurrently. In 2018, Tseng et al. proposed a certificateless signature (CLS) scheme and claimed that their proposal is th...
Article
The wide deployment of Internet of Things (IoT) devices enables the controller to continuously collect massive volume data in automation systems, and makes it possible to make intelligent decisions based on machine learning techniques. In fact, data-driven intelligent automation systems have been common in the industrial community. Nevertheless, ho...
Chapter
Full-text available
Automatic speech recognition (ASR) applications are ubiquitous these days. A variety of commercial products utilize powerful ASR capabilities to transcribe user speech. However, as with other deep learning models, the techniques underlying ASR models suffer from adversarial example (AE) attacks. Audio AEs resemble non-suspicious audio to the casual...
Article
Unlike traditional centralized machine learning, distributed machine learning provides more efficient and useful application scenarios. However, distributed learning may not meet some security requirements. For example, in medical treatment and diagnosis, an increasing number of people are using IoT devices to record their personal data, when train...
Article
In the artificial intelligence era, data-driven computation tasks, such as machine learning, have been playing an essential role as the decision-maker to unlock the value of big data in many fields. Moreover, the ultimate goal of pursuing accuracy and efficiency improvement to better promote the application of data-driven computation has never chan...
Article
Full-text available
Thanks to its convenience and cost-savings feature, cloud computing ushers a new era. Yet its security and privacy issues must not be neglected. Private set intersection (PSI) is useful and important in many cloud computing applications, such as document similarity, genetic paternity and data mining. The cloud server performs intersection operation...
Article
This paper investigates a novel RSA-like cryptosystem proposed by Murru-Saettone. This cryptosystem is constructed from a cubic field connected to the cubic Pell equation and Redei rational functions. The scheme is claimed to be secure against the Wiener-type attack. However, in this paper, we show a Wiener-type attack that can recover the secret k...
Article
Tightly secure signature plays a significant role in the research of cryptography and has been studied extensively in the literature. In this paper, we present a generic construction for tightly-secure signatures from the discrete log (DL) assumption in the existential-unforgeability against key only attacks (EUF-KOA) security model, where the adve...
Article
Full-text available
Linkable ring signatures is a useful cryptographic tool for constructing applications such as ones relative to electronic voting (e-voting), digital cashes (e-cashes) as well as cloud computing. Equipped with linkable ring signatures, e-voting, e-cash systems can simultaneously enjoy the privacy and the unreusability properties thanks to the anonym...
Article
Traditional data sharing systems are facing new challenges when implementing access control with more and more complex data sharing requirements. Flexibility of user revocation in completely decentralized environments needs to be taken into account. In this paper, we propose a Key-Policy Attribute-Based Encryption scheme with Multiple Authorities a...