Biometric cryptosystems present a promising avenue for secure authentication; however, the efficiency and security of such systems can be hindered by errors in biometric data. To address this challenge, existing systems employ error-correction codes, but often fail to consider the distribution of biometric sources, potentially leading to an underestimation of the system’s security. In response to this issue, we propose a novel algorithm pair, designated as ENCODE and DECODE, which facilitates direct codeword generation from biometric samples. Our approach accounts for the distribution of biometric sources, thereby providing a more accurate estimation of system security compared to traditional methods. Our proposed algorithm pair generates codewords that maintain interpretability and are sensitive to the cosine distance between original biometric samples. This similarity metric is particularly well-suited for high-dimensional data analysis and enables a precise assessment of system performance. We have rigorously established the correctness of our algorithm pair, and empirical results illustrate its efficacy in tolerating distance between codewords while preserving accuracy in cosine distance-sensitive contexts. This approach has the potential to significantly improve the efficiency and security of biometric cryptosystems, rendering them more appropriate for daily cryptographic applications.

The key encapsulation mechanism (KEM) is an important cryptographic tool to protect communication in the Internet of Things (IoT). In the near future, classical algorithms used to construct KEMs, such as RSA and elliptic curve cryptography, will be vulnerable to attacks from quantum computers. Recently, Yamada et al. proposed the quasicyclic medium density parity check (QC-MDPC) KEM, which is considered one of the most advanced code-based cryptosystems to resist quantum attacks. In this article, an optimized implementation of QC-MDPC KEM for IoT applications is presented. Our main contributions are threefold: 1) the fastest QC-MDPC McEliece decryption in field-programmable gate array (FPGA); 2) the first QC-MDPC KEM implementation in FPGA; and 3) the first iteration count attack-resistant QC-MDPC decoder in FPGA. To improve the decryption speed, we introduce a novel customized rotation engine (CRE) and incorporated several recent techniques reported in the literature, including adaptive threshold and Hamming weight estimation. The best-achieved throughput in our implementation on Xilinx Virtex 7 FPGA is 12.7% faster than the state-of-the-art result reported by Heyse et al. The proposed CRE was then integrated with QC-MDPC KEM to produce a fast and secure KEM. Furthermore, to prevent timing attacks demonstrated recently, a constant-time implementation of the QC-MDPC McEliece decoder was presented.

Postquantum cryptography attracts a lot of attention from the research community recently due to the emergence threat from quantum computer toward the conventional cryptographic schemes. In view of that, NIST had initiated the standardization process in 2017. Bit flipping key encapsulation (BIKE) designed by Aragon et al. is one of the promising code-based schemes among the round-3 candidates. BIKE utilizes a quasi-cyclic medium density parity check (QC-MDPC) code and incorporates a few variants derived from the McEliece, Niederreiter, and Ouroboros schemes. In this article, we present efficient and constant time implementation of BIKEI and BIKE-III in field-programmable gate array (FPGA), which has the best area-time efficiency so far. We proposed modification to the original one-round bit flipping algorithm to achieve more area-time-efficient decoding in hardware, which achieved latency of 464.73 and 556.52 μs for BIKE-I and BIKE-III, respectively, in Virtex-7. A pipelined key encapsulation architecture is proposed to speedup the key encapsulation of BIKE-I and BIKE-III, achieving the latency of 146.47 and 153.25 μs on the same FPGA platform. Considering the Artix-7 FPGA platform, our combined key generation and encapsulation module for BIKE-I is also three more area-time efficient compared with the state-of-the-art BIKE-I implementation by Aragon et al.

Summary With the emergence of IoT and cloud computing technologies, massive data are generated from various applications everyday and communicated through the Internet. Secure communication is essential to protect these data from malicious attacks. Block ciphers are one mechanism to offer such protection but unfortunately involve intensive computations that can be performance bottlenecks to the servers, especially when the data center needs to handle thousands of concurrent transactions. In this paper, we investigate the feasibility of the GPU as an accelerator to perform high‐speed encryption in server environments. We present optimized implementations of a conventional block cipher (AES) and new lightweight block ciphers (LEA, Chaskey, SIMON, SPECK, and SIMECK) across three new GPU architectures (Kepler, Maxwell, and Pascal). For AES, we improve the fine‐grain implementation by utilizing the warp shuffle instruction available in these three new GPU architectures, which yield a 6%‐16% improvement over the previous implementations. For LEA, Chaskey, SIMON, SPECK, and SIMECK, we first analyze why they cannot have efficient fine‐grain implementations in the GPU and then present our optimization techniques, which are able to achieve impressive encryption speeds of 1.912, 637, 1.485, 2.291, and 1.478 Tb/s, respectively, in GTX1080.

The emergence of Internet of Things (IoT) brings us the possibility to form a well connected network for ubiquitous sensing, intelligent analysis, and timely actuation, which opens up many innovative applications in our daily life. To secure the communication between sensor nodes, gateway devices and cloud servers, cryptographic algorithms (e.g., digital signature, block cipher, and hash function) are widely used. Although cryptographic algorithms are effective in preventing malicious attacks, they involve heavy computation that may not be executed efficiently in resource constraint sensor nodes. In particular, the authentication of a sensor node is usually performed through a digital signature (e.g., RSA and elliptic curve cryptography), which can be slow when executed on a microcontroller. In this paper, an IoT architecture that offloads the digital signature generation to a nearby signature gateway equipped with graphic processing unit (GPU) accelerator are proposed. The communication process for signature offloading, together with optimized implementation techniques for RSA in signature gateway, are also presented in this paper. We have evaluated two different ways to implement modular exponentiation in RSA, namely residue number system and multiprecision montgomery multiplication (MPMM). The experimental results show that our RSA implementation using MPMM is 10.1% faster than the best RSA implementation in GPU. Our proposed IoT architecture with signature gateway can successfully reduce the burden of sensor nodes to generate signatures, at the same time preserve the ability to authenticate the sensor nodes.

Encryption is primarily used to ensure the confidentiality of information transmitted over an insecure wireless channel. However, an encrypted signal may be received with some errors due to noise and interference in the wireless channel. To alleviate these errors in the received encrypted signal, Zibideh and Matalgah proposed two different versions of key‐based coded permutation cipher (KBCPC) aimed to improve the error performance and security of the transmission in the wireless channel. These two versions were designed based on the modified data encryption standard (M‐DES) and provide different levels of security. This study presents a divide‐and‐conquer attack on both M‐DES and KBCPC by exploiting the function that extends the length of output. Their analysis shows that these two ciphers can only provide 56‐bit level of security instead of the claimed 136‐bit and 173.67‐bit level of security for different versions. The authors' analysis is further verified through experiments. More importantly, their attack can be easily adapted to other schemes with a different encryption design but the same coding technique used in M‐DES or KBCPC.

This paper explores the recently published works on iris template protection namely Indexing-First-One hashing. Despite the Indexing-First-One hashing offers high recognition performance with resistant against several major privacy and security attacks, it does not resolve the rotation inconsistent issues existed in conventional iris template due to head tilt/rotation during user's eyes images acquisition. Hence, a pre-alignment step is required for the conventional IFO hashed code matching. Consequently, this increased the computational cost heavily. Hereby, we address the rotation inconsistent issue by proposing an alignment-free IFO hashing through a pre-transformation based on Bloom filter generation. The proposed pre-alignment IFO hashing shows promising recognition performance, and the pre-alignment procedure is eliminated to lower computational cost.

Rateless erasure code (REC) is an erasure code, where the encoder generates a potentially infinite number of encoded symbols and the original message can be reconstructed from a sufficient number of correctly received packets. Many REC-based transmission protocols have been proposed for improving network throughput in lossy channel. However, state-of-the-art RECs (such as LT code and Raptor code) are not efficient for transmitting short messages. Recent studies suggest that network traffic is characterised by bursts of short messages and thus existing transmission protocols do not benefit from the gains of deploying REC. In this paper, we propose an REC-based transmission protocol, namely UDP-RC, which integrates the simplicity of UDP and strength of systematic Random code suited to network traffic with short messages. It attains high throughput by transmitting short messages reliably with lower overheads over lossy channel. We experimentally show that UDP-RC achieves at least 50% higher throughput and maintains more stable throughput compared to TCP (Transmission Control Protocol) and UDT (UDP Data transfer) protocol under both ideal and lossy channel conditions.

The ISO/IEC 19794-2-compliant fingerprint minutiae template is an unordered and variable-sized point set data. Such a characteristic leads to a restriction for the applications that can only operate on fixed-length binary data, such as cryptographic applications and certain biometric cryptosystems (e.g., fuzzy commitment). In this paper, we propose a generic point-to-string conversion framework for fingerprint minutia based on kernel learning methods to generate discriminative fixed length binary strings, which enables rapid matching. The proposed framework consists of four stages: (1) minutiae descriptor extraction; (2) a kernel transformation method that is composed of kernel principal component analysis or kernelized locality-sensitive hashing for fixed length vector generation; (3) a dynamic feature binarization; and (4) matching. The promising experimental results on six datasets from fingerprint verification competition (FVC)2002 and FVC2004 justify the feasibility of the proposed framework in terms of matching accuracy, efficiency, and template randomness.

Random code is a rateless erasure code that can reconstruct the original message of k symbols from any k + 10 encoded symbols with high probability of complete decoding (PCD), i.e. 99.9% successful decoding, irrespective of the message length, k . Nonetheless, random code is inefficient in reconstructing short messages. For example, a message of k = 10 symbols requires k + 10 = 20 encoded symbols, i.e. two times the original message length in order to achieve high PCD. In this study, the authors propose micro‐random code that encodes and decodes the original message using symbols of smaller dimensions, namely micro symbols. The authors’ analysis and numerical simulations show that micro‐random code achieves high PCD with only k + 1 encoded symbols. As the trade‐off for such a gain, the number of steps for decoding increases exponentially with each incrementing segmentation factor, α . In addition, the numerical results show that the decoding time increases by about 400% at α = 10, depending on the processing power of the system.

In 2011, Eissa, Razak and Ngadi proposed a lightweight authentication and encryption scheme to enhance the performance for mobile ad hoc network in Wireless Network, Vol. 17, No. 4, 2011. The main building block of such scheme is an identity-based encryption scheme. The scheme was proven secure in the random oracle model assuming the computational Diffie–Hellman assumption is hard. In this paper, we show that the proposed scheme is not even secure against chosen plaintext attack, which is the lowest acceptable level of security. In addition, we demonstrate the RSA parameter suggested by Eissa et al. to yield a better network performance is not appropriate under a wrong security assumption that each mobile node is totally trusted. Such short RSA parameter leads to a key recovery attack.

ABSTRACT With the massive deployment of biometric applications, protecting the biometric template has attracted great attention because of the privacy issue. Although many proposals on protecting biometric template have been reported in literature, design a method simultaneously satisfying four criteria, that is performance, non‐invertibility, cancellability, and diversity still remains unsolved. In this paper, we proposed a two‐dimensional random projected minutiae vicinity decomposition (MVD) technique to secure minutiae‐based fingerprint template. Minutiae vicinity is first formed from a set of fingerprint minutiae and further used to generate a set of local features, namely MVD features; then, a random matrix derived from user‐specific token is used to project MVD features for the concealment of the topology of MVD. Comprehensive experiments on fingerprint verification competition datasets are carried out, and the lowest equal error rate obtained in the stolen‐token scenario is 3.07% and 1.02% for fingerprint verification competition 2002 database 1 and database 2, respectively. Besides, detail analyses on the irreversibility, cancellability, template size, and computational cost have been carried out. Copyright © 2013 John Wiley & Sons, Ltd.

Cloud computing provides on demand computation and storage services delivered via applications, system software and hardware rendered as services. Due to its on demand nature, it has high variable workloads and requires real-time efficiency and availability. Most cloud computing systems use a centralised model to provision services, but reliance on a central entity to control scheduling decision and maintain all cloud hosts may constitute a computing bottleneck. A system failure will cause service outage, sometimes for a few hours as had happened before. In addition, the central entity needs to support heavy workloads in terms of service provisioning to all resource hosts. These issues can be addressed by distributing cloud resources using structured peer-to-peer (P2P) overlay networks as was recently proposed. However these proposals do not examine potential security issues of a P2P-based cloud, one of them being how peers verify the identities of one another over a decentralised setting. Therefore we propose an authentication framework for P2P cloud consisting of various approaches for authenticating entities and messages. The framework combines cryptographic primitives and security mechanisms proposed for existing structured P2P network.

ABSTRACT Fuzzy identity‐based identification (FIBI) scheme is a recently proposed cryptographic identification protocol. The scheme utilizes user biometric trait as public keys. The authentication is deemed success in the presence of the genuine query biometric together with the valid private key. Because of the fuzziness nature of biometrics, FIBI does not correct the errors on the query biometric with respect to the public key; instead, it tolerates the errors using Lagrange polynomial interpolation. Therefore, FIBI requires the biometric trait to be represented in a discrete (binary or integer) array that is fixed in length. In this paper, we report the first realization of FIBI scheme by means of fingerprint biometrics using minutia representation where our technique integrates the security features of both biometric and cryptography effectively. The simulation shows that the entire protocol can be completed within 1 s where false acceptance rate (FAR) = 0% and false reject rate (FRR) = 0.25% in FVC2002 DB1, and FAR = 0% and FRR = 0.125% in FVC2002 DB2. Our integration technique may also be applied on other fuzzy identity‐based cryptosystems. Copyright © 2012 John Wiley & Sons, Ltd.

ABSTRACT On these days, users tend to access to online content via mobile devices, for example, e‐mails. Because these devices have constrained resources, users may wish to instruct e‐mail gateways to search through new e‐mails and only download those corresponding to particular keywords, such as “urgent.” Yet, this searching should not compromise the user's privacy. A public key encryption with keyword search (PEKS) scheme achieves both these requirements. Most PEKS schemes are constructed on the basis of bilinear pairings. Recently, Khader proposed the first PEKS scheme that does not require bilinear pairings and is provably indistinguishable chosen‐keyword attack (IND‐CKA) secure in the standard model. Such a scheme is more efficient than pairing‐based ones. In this paper, we show a drawback of Khader's scheme in that it depends on an unnecessary security assumption: Its IND‐CKA security requires its underlying identity‐based encryption building block to be indistinguishable chosen‐ciphertext attack secure. We construct a more efficient PEKS scheme that achieves the same level of PEKS security as Khader's but that only requires the underlying identity‐based encryption to be indistinguishable chosen‐plaintext attack secure. We give a direct proof that the proposed scheme is IND‐CKA secure. Our scheme outperforms other recent PEKS schemes in literature. Copyright © 2012 John Wiley & Sons, Ltd.

Password-Authenticated Key Exchange (PAKE) protocols allow parties to share secret keys in an authentic manner based on an easily memorizable password. Recently, Nam et al. showed that a provably secure three-party password-based authenticated key exchange protocol using Weil pairing by Wen et al. is vulnerable to a man-in-the-middle attack. In doing so, Nam et al. showed the flaws in the proof of Wen et al. and described how to fix the problem so that their attack no longer works. In this paper, we show that both Wen et al. and Nam et al. variants fall to key compromise impersonation by any adversary. Our results underline the fact that although the provable security approach is necessary to designing PAKEs, gaps still exist between what can be proven and what are really secure in practice.