Towards Post-Quantum Blockchain: A Review on Blockchain Cryptography Resistant to Quantum Computing Attacks

[Abstract] Blockchain and other Distributed Ledger Technologies (DLTs) have evolved significantly in the last years and their use has been suggested for numerous applications due to their ability to provide transparency, redundancy and accountability. In the case of blockchain, such characteristics are provided through public-key cryptography and hash functions. However, the fast progress of quantum computing has opened the possibility of performing attacks based on Grover's and Shor's algorithms in the near future. Such algorithms threaten both public-key cryptography and hash functions, forcing to redesign blockchains to make use of cryptosystems that withstand quantum attacks, thus creating which are known as post-quantum, quantum-proof, quantum-safe or quantum-resistant cryptosystems. For such a purpose, this article first studies current state of the art on post-quantum cryptosystems and how they can be applied to blockchains and DLTs. Moreover, the most relevant post-quantum blockchain systems are studied, as well as their main challenges. Furthermore, extensive comparisons are provided on the characteristics and performance of the most promising post-quantum public-key encryption and digital signature schemes for blockchains. Thus, this article seeks to provide a broad view and useful guidelines on post-quantum blockchain security to future blockchain researchers and developers.10.13039/501100010801-Xunta de Galicia (Grant Number: ED431G2019/01) 10.13039/501100011033-Agencia Estatal de Investigación (Grant Number: TEC2016-75067-C4-1-R and RED2018-102668-T) 10.13039/501100008530-European Regional Development FundXunta de Galicia; ED431G2019/0

Public-key Authenticated Encryption with Keyword Search: A Generic Construction and Its Quantum-resistant Instantiation

The industrial Internet of Things (IIoT) integrates sensors, instruments, equipment, and industrial applications, enabling traditional industries to automate and intelligently process data. To reduce the cost and demand of required service equipment, IIoT relies on cloud computing to further process and store data. Public-key encryption with keyword search (PEKS) plays an important role, due to its search functionality, to ensure the privacy and confidentiality of the outsourced data and the maintenance of flexibility in the use of the data. Recently, Huang and Li proposed the ``public-key authenticated encryption with keyword search\u27\u27 (PAEKS) to avoid the insider keyword guessing attacks (IKGA) in the previous PEKS schemes. However, all current PAEKS schemes are based on the discrete logarithm assumption and are therefore vulnerable to quantum attacks. In this study, we first introduce a generic PAEKS construction, with the assistance of a trusted authority, that enjoys the security against IKGA in the standard model, if all building blocks are secure under standard model. Based on the framework, we further propose a novel instantiation of quantum-resistant PAEKS that is based on NTRU assumption under random oracle. Compared with its state-of-the-art counterparts, the experiment result indicates that our instantiation is more efficient and secure

Secure Hardware Implementation of Post Quantum Cryptosystems

Solving a hard mathematical problem is the security basis of all current cryptographic systems. With the realization of a large scale quantum computer, hard mathematical problems such as integer factorization and discrete logarithmic problems will be easily solved with special algorithms implemented on such a computer. Indeed, only post-quantum cryptosystems which defy quantum attacks will survive in the post-quantum era. Each newly proposed post-quantum cryptosystem has to be scrutinized against all different types of attacks. Attacks can be classified into mathematical cryptanalysis and side channel attacks. In this thesis, we propose secure hardware implementations against side channel attacks for two of the most promising post-quantum algorithms: the lattice-based public key cryptosystem, NTRU, and the multivariate public key cryptosystem, Rainbow, against power analysis attacks and fault analysis attacks, respectively. NTRUEncrypt is a family of public key cryptosystems that uses lattice-based cryptography. It has been accepted as an IEEE P1363 standard and as an X9.98 Standard. In addition to its small footprint compared to other number theory based public key systems, its resistance to quantum attacks makes it a very attractive candidate for post quantum cryptosystems. On the other hand, similar to other cryptographic schemes, unprotected hardware implementations of NTRUEncrypt are susceptible to side channel attacks such as timing and power analysis. In this thesis, we present an FPGA implementation of NTRUEncrypt which is resistant to first order differential power analysis (DPA) attacks. Our countermeasures are implemented at the architecture level. In particular, we split the ciphertext into two randomly generated shares. This guarantees that during the first step of the decryption process, the inputs to the convolution modules, which are convoluted with the secret key polynomial, are uniformly chosen random polynomials which are freshly generated for each convolution operation and are not under the control of the attacker. The two shares are then processed in parallel without explicitly combining them until the final stage of the decryption. Furthermore, during the final stage of the decryption, we also split the used secret key polynomial into two randomly generated shares which provides theoretical resistance against the considered class of power analysis attacks. The proposed architecture is implemented using Altera Cyclone IV FPGA and simulated on Quartus II in order to compare the non-masked architecture with the masked one. For the considered set of parameters, the area overhead of the protected implementation is about 60% while the latency overhead is between 1.4% to 6.9%. Multivariate Public Key Cryptosystems (MPKCs) are cryptographic schemes based on the difficulty of solving a set of multivariate system of nonlinear equations over a finite field. MPKCs are considered to be secure against quantum attacks. Rainbow, an MPKC signature scheme, is among the leading MPKC candidates for post quantum cryptography. In this thesis, we propose and compare two fault analysis-resistant implementations for the Rainbow signature scheme. The hardware platform for our implementations is Xilinx FPGA Virtex 7 family. Our implementation for the Rainbow signature completes in 191 cycles using a 20ns clock period which is an improvement over the previously reported implementations. The verification completes in 141 cycles using the same clock period. The two proposed fault analysis-resistant schemes offer different levels of protections and increase the area overhead by a factor of 33% and 9%, respectively. The first protection scheme acquires a time overhead of about 72%, but the second one does not have any time overhead

On some methods for constructing almost optimal S-Boxes and their resilience against side-channel attacks

Substitution Boxes (S-Boxes) are crucial components in the design of many symmetric ciphers. The security of these ciphers against linear, differential, algebraic cryptanalyses and side-channel attacks is then strongly dependent on the choice of the S-Boxes. To construct S-Boxes having good resistive properties both towards classical cryptanalysis as well side-channel attacks is not a trivial task. In this article we propose new methods for generating S-Boxes with strong cryptographic properties and therefore study the resilience of such S-Boxes against side-channel attacks in terms of its theoretical metrics and masking possibility

Horizon 2020-funded security research projects with dual-use potential: An overview (2014-2018)

The analysis carried out in this report facilitates the identification of dual-use research topics and projects funded under Horizon 2020 that have a dual-use civilian/military potential, the results of which could be applied both by security and defence stakeholders (including industry). In this way, it could support the future security and defence research programmes in their attempt of avoiding duplication of investments and promoting synergies.JRC.E.7-Knowledge for Security and Migratio

Internet of Things 2.0: Concepts, Applications, and Future Directions

Applications and technologies of the Internet of Things are in high demand with the increase of network devices. With the development of technologies such as 5G, machine learning, edge computing, and Industry 4.0, the Internet of Things has evolved. This survey article discusses the evolution of the Internet of Things and presents the vision for Internet of Things 2.0. The Internet of Things 2.0 development is discussed across seven major fields. These fields are machine learning intelligence, mission critical communication, scalability, energy harvesting-based energy sustainability, interoperability, user friendly IoT, and security. Other than these major fields, the architectural development of the Internet of Things and major types of applications are also reviewed. Finally, this article ends with the vision and current limitations of the Internet of Things in future network environments

Security and defence research in the European Union: a landscape review

This landscape report describes the state of play of the European Union’s policies and activities in security and defence and the EU-funded research aimed at supporting them, with an exclusive focus on intentional harm. It is organised around several thematic building blocks under the umbrella of the three core priorities defined in the European agenda on security. The report reviews the current main risks and threats but also those that may emerge within the next 5 years, the policy and operational means developed to combat them, the main active stakeholders and the EU legislation in force. In this context, a short history of EU research on security and defence is presented, followed by an inventory of relevant research and development projects funded under the Horizon 2020 framework programme during the period 2014-2018. The specific contributions of the Joint Research Centre to security research are also highlighted. Finally, future avenues for security and defence research and development are discussed. Please note that the executive summary of this landscape report has been published simultaneously as a companion document.JRC.E.7-Knowledge for Security and Migratio