Blockchain Papers

Nicholas Kolokotronis, Konstantinos Limniotis, Stavros Shiaeles, Romain Griffiths

Blockchain is a disruptive technology that has been characterised to be the next big thing and has already gained a broad recognition by experts in diverse fields. In this paper, we consider possible use cases and applications of the blockchain for the consumer electronics (CE) industry and its interplay with the Internet of things. Instead of discussing how the blockchain can revolutionise the supply chain, we focus on how it could be employed for enhancing the security of networked CE devices. This work is motivated by the large number of recent attacks that use easily hackable devices as a weaponry. Towards this direction, privacy and data protection aspects of blockchain solutions are also presented and are linked to regulatory framework provisions. Information on existing blockchain solutions is also provided.

Hiroshi Watanabe, Howie Fan

The widespread computer network has been changing drastically and substantially since blockchain and IoT entered the stage. Blockchain is good at protecting data transactions between logical nodes with a desirable guaranty. Internet of Things (IoT), on the other hand, by providing ultimate convenience to consumers, is expected to give rise to many various merits in a broad business scene. The security of IoT is still an open problem and if blockchain can reinforce IoT security, as many authors have hoped in recent papers, these newcomers appear to make a good collaboration to reinforce IoT security. However, software copes with logical nodes and IoT involves a vast number of physical nodes (IoT devices). Enabling blockchain to protect IoT cannot be brought to reality without respectively identifying logical and physical nodes. This is identical to the Proof-of-Trust problem. In this article, we propose a conceptual solution—Blockchained IoT—and show that this concept is able to be realized on-chip level using mass-produced dynamical random access memory (DRAM). We have completed the first test of longevity and temperature dependence (−40 °C to 105 °C) to confirm the necessary characteristics for the 5G base stations that are known to have an issue of self-heating. Furthermore, we have coarsely evaluated the probability of two DRAM IC chips being associated with an identical cyber-physical chip identification accidentally. Then, such a probability is minimal.

Sabah Suhail, Rasheed Hussain, Abid Khan, Choong Seon Hong

"Trustworthy data" is the fuel for ensuring transparent traceability, precise decision-making, and cogent coordination in the supply chain (SC) space. However, the disparate data silos act as a trade barrier in orchestrating the provenance of product story starting from the transformation of raw materials into the circuit board to the assembling of electronic components into end products available on the store shelf for customers. Therefore, to bridge the fragmented siloed information across global supply chain partners, the diffusion of blockchain (BC) as one of the advanced distributed ledger technology (DLT) takeover the on-premise legacy systems. Nevertheless, the challenging constraints of blockchain including scalability, accessing off-line data, fee-less microtransactions and many more lead to the third wave of blockchain called IOTA. In this paper, we propose a framework for supporting provenance in the electronic supply chain (ECS) by using permissioned IOTA ledger. Realizing the crucial requirement of trustworthy data, we use Masked Authenticated Messaging (MAM) channel provided by IOTA that allows the SC players to procure distributed information while keeping confidential trade flows, tamper-proof data, and fine-grained accessibility rights. To identify operational disruption, we devise a transparent product ledger through transaction data and consignment information to keep track of the complete product journey at each intermediary step during SC processes. Furthermore, we evaluate the secure provenance data construction time for varying payload size.

Changhao Chenli, Boyang Li, Yiyu Shi, Taeho Jung

An enormous amount of energy is wasted in Proofof-Work (PoW) mechanisms adopted by popular blockchain applications (e.g., PoW-based cryptocurrencies), because miners must conduct a large amount of computation. Owing to this, one serious rising concern is that the energy waste not only dilutes the value of the blockchain but also hinders its further application. In this paper, we propose a novel blockchain design that fully recycles the energy required for facilitating and maintaining it, which is re-invested to the computation of deep learning. We realize this by proposing Proof-of-Deep-Learning (PoDL) such that a valid proof for a new block can be generated if and only if a proper deep learning model is produced. We present a proof-of-concept design of PoDL that is compatible with the majority of the cryptocurrencies that are based on hash-based PoW mechanisms. Our benchmark and simulation results show that the proposed design is feasible for various popular cryptocurrencies such as Bitcoin, Bitcoin Cash, and Litecoin.

Md. Mehedi Hassan Onik, Chul‐Soo Kim, Jinhong Yang

Fourth industrial revolution (Industry 4.0) promises a connected and smart manufacturing system where internet, machine (physical system) and humans lumped together. Unlike other industrial revolutions, this industrial revolution deals more with information. Device to device (D2D) and Machine to Machine (M2M) communications often generate, preserve and share private information. Personal data has already turned out to be a new commodity and currently identified as a ‘new oil’ or ‘new domain of warfare’. The more information gets generated and accumulated, the more extensive and risky the personal information becomes. Although privacy and security are often bundled together, they are different. This study investigates the privacy attack surfaces of key Industry 4.0 components (i.e. Cyber-Physical System, Artificial Intelligence, additive manufacturing, autonomous vehicle, big data, cloud computing, internet of things, distributed ledger etc). Multi-dimensional privacy challenges, data breaching incidents, regulations and need of a contextual privacy awareness is discussed in this study. Finally, this work elaborates the risk of Personally Identifiable Information (PII) leaking in the era of industry 4.0.

Adrien Ghosn, James R. Larus, Edouard Bugnion

Trusted Execution Environments (TEEs), such as Intel SGX enclaves, use hardware to ensure the confidentiality and integrity of operations on sensitive data. While the technology is available on many processors, the complexity of its programming model and its performance overhead have limited adoption. TEEs provide a new and valuable hardware functionality that has no obvious analogue in programming languages, which means that developers must manually partition their application into trusted and untrusted components. This paper describes an approach that fully integrates trusted execution into a language. We extend the Go language to allow a programmer to execute a goroutine within an enclave, to use low-overhead channels to communicate between the trusted and untrusted environments, and to rely on a compiler to automatically extract the secure code and data. Our prototype compiler and runtime, GOTEE, is a backward-compatible fork of the Go compiler. The evaluation shows that our compiler-driven code and data partitioning efficiently executes both microbenchmarks and applications. On the former, GOTEE achieves a 5.2×throughput and a 2.3× latency improvement over the Intel SGX SDK. Our case studies, a Go ssh server, the Go tls package, and a secured keystore inspired by the go-ethereum project, demonstrate that minor source-code modifications suffice to provide confidentiality and integrity guarantees with only moderate performance overheads.

Mohsin Kamal, Muhammad Tariq

The protection of smart meters (SMs) from cyberattacks is of utmost importance because SMs in advanced metering infrastructure (AMI) are physically unprotected and produce a large amount of sensitive data. Due to scalability, the SMs are small-sized and low-cost devices having low computational capabilities. The algorithms that are designed to complete the security requirements of SMs should be lightweight. To address this issue, this paper proposes a lightweight security solution to address the man-in-the-middle attack, data tempering, and blockchain-based data provenance. Received signal strength indicator (RSSI) is used to generate link fingerprints, which are used along with pseudo-random nonce to secure AMI. The proposed algorithm detects the involvement of adversarial node or meter tempering by computing other values along with 0 and 1 as the average of consecutive RSSI and difference between the RSSI of connected static SMs. Pearson correlation coefficient (ρ) of 0.9102 is achieved when no adversarial node is present in between the connected SMs having mobility in one or both SMs. Negative or approximately equal to zero values of ρ are computed when the adversary is present in the AMI or any of the SM in the AMI is forged. For blockchain-based data provenance, all the hash values of the packet header are 100% matched with the hash functions present at the data concentrator unit (DCU), which shows no adversary's involvement in AMI. For cases when the adversary is in the AMI, hash functions show no match with the hash values present at the DCU.

Pinchen Cui, Julie Dixon, Ujjwal Guin, Daniel DiMase

The complexity of the electronics supply chain has grown significantly due to the expansion of globalization in the 21st century. Electronic parts are now manufactured, distributed, and sold globally. Ensuring the security and integrity of the supply chain has become extremely challenging due to the widespread infiltration of untrusted hardware, specifically, counterfeit and cloned parts. Especially, the provenance of microelectronics and commercial off-the-shelf (COTS) parts becomes prohibitively difficult to track and calls for immediate solutions. In this paper, we present a non-destructive way of ensuring the traceability of electronic parts in the supply chain. We have implemented a blockchain-based framework, which helps to track and trace every chip while they are circulating in the supply chain. The proposed framework is built upon a permissioned blockchain. Hyperledger is used for implementing this framework. A detailed analysis is carried out to present the feasibility of our proposed approach.

Alexander Schönhals, Thomas Hepp, Béla Gipp

In this vision paper, we present an approach that makes it possible to protect developed ideas and early concepts even during their systematical development. We take the Design Thinking process as an example, in which interfaces are used for individual stages (understand, observe, define, ideate, prototype, test) to digitally record verbal, written or sketched, and even modeled or constructed outcome. This outcome is recorded and linked to the originating person. To guarantee both proof-of-existence and proof-of-origin, a unique hash is generated from each digital artifact stored and embedded into the Bitcoin Blockchain by the OriginStamp decentralized trusted timestamping service. Once this unique fingerprint is embedded in a transaction in the underlying Blockchain network, it can be proven where particular contributions originated due to the characteristics of Blockchain architecture. By setting up a decentralized tamper-proof means of record keeping, the entire innovation chain from the first ideation to the beginning of production is verifiably stored. By providing a clear proof-of-origin, all innovators (even competitors) could continue to work on existing problem-solving process and add their contribution proportionately, depending on the state of innovation development. This concept enables an Open Innovation ecosystem, which has the potential to increase the innovation potential of companies immensely. Additionally, inventions that are not patentable because they do not comply with the strict regulations of patent law can still be published and protected because the information about the origin of the respective contribution is guaranteed.

Thomas Hepp, Patrick Wortner, Alexander Schönhals, Béla Gipp

The use of blockchain technology to track physical assets is not new. However, the state of the art concepts are not applicable due to several limitations. One limitation is the scalability of blockchains with regard to the number of transactions that can be processed by the network. The well-established technology in tracking products is based on RFID chips that can be cloned. This paper provides insights into how objects can be protected and monitored by a varnish with a unique crack pattern, as an example of a Physical Unclonable Function. The perceptual hash of the unique pattern is used to encrypt the associated data to ensure privacy. Instead of logging each event on the blockchain individually, which is not possible due to the limited transaction throughput, OriginStamp is used to preserve data integrity on the blockchain. OriginStamp aggregates events, combines them through hashing and embeds this hash into a Bitcoin transaction. Once the Bitcoin network mines the transaction into a block and confirms it, the timestamp is considered as immutable proof of existence. With this approach, the integrity of tracking data cannot be contested.

Norsefire, ToCsIcK

This paper introduces the underlying mechanics and interface for PhoeniχCoin (PHX), an Ethereum ERC223-compliant cryptocurrency. The supply of PHX tokens is tied directly to the Ethereum balance of the smart contract underpinning the ‘EthPhoenix’ decentralised application, and mined using a novel, generalisable technique we refer to as proof-of-volatility.

Sean Rowan, Michael Clear, Mário Gerla, Meriel Huggard · 5 authors

Autonomous and self-driving vehicles are appearing on the public highways.\nThese vehicles commonly use wireless communication techniques for both\nvehicle-to-vehicle and vehicle-to-infrastructure communications. Manufacturers,\nregulators and the public are understandably concerned about large-scale\nsystems failure or malicious attack via these wireless vehicular networks. This\npaper explores the use of sensing and signalling devices that are commonly\nintegrated into modern vehicles for side-channel communication purposes.\nVisible light (using a CMOS camera) and acoustic (ultrasonic audio)\nside-channel encoding techniques are proposed, developed and evaluated in this\ncontext. The side-channels are examined both theoretically and experimentally\nand an upper bound on the line code modulation rate that is achievable with\nthese side channel schemes in the vehicular networking context is established.\nA novel inter-vehicle session key establishment protocol, leveraging both\nside-channels and a blockchain public key infrastructure, is then presented. In\nlight of the limited channel capacity and the interoperability/security\nrequirements for vehicular communications, techniques for constraining the\nthroughput requirement, providing device independence and validating the\nlocation of the intended recipient vehicle, are presented. These reduce the\nnecessary device handshake throughput to 176 bits for creating symmetric\nencryption and message authentication keys and in verifying a vehicle's\ncertificate with a recognised certification authority.\n

Jonathan Bootle, Andrea Cerulli, Essam Ghadafi, Jens Groth · 6 authors

No abstract is available for this record.

Siguna Mueller, Farhad Jafari, Don Roth

BACKGROUND: Proliferation and expansion of security risks necessitates new measures to ensure authenticity and validation of GMOs. Watermarking and other cryptographic methods are available which conceal and recover the original signature, but in the process reveal the authentication information. In many scenarios watermarking and standard cryptographic methods are necessary but not sufficient and new, more advanced, cryptographic protocols are necessary. RESULTS: Herein, we present a new crypto protocol, that is applicable in broader settings, and embeds the authentication string indistinguishably from a random element in the signature space and the string is verified or denied without disclosing the actual signature. Results show that in a nucleotide string of 1000, the algorithm gives a correlation of 0.98 or higher between the distribution of the codon and that of E. coli, making the signature virtually invisible. CONCLUSIONS: This algorithm may be used to securely authenticate and validate GMOs without disclosing the actual signature. While this protocol uses watermarking, its novelty is in use of more complex cryptographic techniques based on zero knowledge proofs to encode information.

Ulrich Rührmair, J. L. Martínez-Hurtado, Xiaolin Xu, Christian Kraeh · 8 authors

We discuss the question of how physical statements can be proven over digital communication channels between two parties (a "prover" and a "verifier") residing in two separate local systems. Examples include: (i) "a certain object in the prover's system has temperature X°C", (ii) "two certain objects in the prover's system are positioned at distance X", or (iii) "a certain object in the prover's system has been irreversibly altered or destroyed". As illustrated by these examples, our treatment goes beyond classical security sensors in considering more general physical statements. Another distinctive aspect is the underlying security model: We neither assume secret keys in the prover's system, nor do we suppose classical sensor hardware in his system which is tamper-resistant and trusted by the verifier. Without an established name, we call this new type of security protocol a "virtual proof of reality" or simply a "virtual proof" (VP). In order to illustrate our novel concept, we give example VPs based on temperature sensitive integrated circuits, disordered optical scattering media, and quantum systems. The corresponding protocols prove the temperature, relative position, or destruction/modification of certain physical objects in the prover's system to the verifier. These objects (so-called "witness objects") are prepared by the verifier and handed over to the prover prior to the VP. Furthermore, we verify the practical validity of our method for all our optical and circuit-based VPs in detailed proof-of-concept experiments. Our work touches upon, and partly extends, several established concepts in cryptography and security, including physical unclonable functions, quantum cryptography, interactive proof systems, and, most recently, physical zero-knowledge proofs. We also discuss potential advancements of our method, for example "public virtual proofs" that function without exchanging witness objects between the verifier and the prover.

Itai Dinur, Yunwen Liu, Willi Meier, Qingju Wang

Abstract. LowMC is a collection of block cipher families introduced at Eurocrypt 2015 by Albrecht et al. Its design is optimized for instanti-ations of multi-party computation, fully homomorphic encryption, and zero-knowledge proofs. A unique feature of LowMC is that its internal affine layers are chosen at random, and thus each block cipher family contains a huge number of instances. The Eurocrypt paper proposed two specific block cipher families of LowMC, having 80-bit and 128-bit keys. In this paper, we mount interpolation attacks (algebraic attacks intro-duced by Jakobsen and Knudsen) on LowMC, and show that a practically significant fraction of 2−38 of its 80-bit key instances could be broken 223 times faster than exhaustive search. Moreover, essentially all instances that are claimed to provide 128-bit security could be broken about 1000 times faster. In order to obtain these results, we had to develop novel techniques and optimize the original interpolation attack in new ways. While some of our new techniques exploit specific internal properties of LowMC, others are more generic and could be applied, in principle, to any block cipher.

Alessandra Scafuro

This thesis proposes several protocols for achieving secure com- putation under concurrent and physical attacks. Secure computation allows many parties to compute a joint function of their inputs, while keeping the privacy of their input preserved. It is required that the pri- vacy one party's input is preserved even if other parties participating in the protocol collude or deviate from the protocol. In this thesis we focus on concurrent and physical attacks, where adversarial parties try to break the privacy of honest parties by ex- ploiting the network connection or physical weaknesses of the honest parties' machine. In the rst part of the thesis we discuss how to construct proto- cols that are Universally Composable (UC for short) based on physical setup assumptions. We explore the use of Physically Uncloneable Func- tions (PUFs) as setup assumption for achieving UC-secure computa- tions. PUF are physical noisy source of randomness. The use of PUFs in the UC-framework has been proposed already in [14]. However, this work assumes that all PUFs in the system are trusted. This means that, each party has to trust the PUFs generated by the other parties. In this thesis we focus on reducing the trust involved in the use of such PUFs and we introduce the Malicious PUFs model in which only PUFs generated by honest parties are assumed to be trusted. Thus the secu- rity of each party relies on its own PUF only and holds regardless of the goodness of the PUFs generated/used by the adversary. We are able to show that, under this more realistic assumption, one can achieve UC- secure computation, under computational assumptions. Moreover, we show how to achieve unconditional UC-secure commitments with (ma- licious) PUFs and with stateless tamper-proof hardware tokens. We discuss our contribution on this matter in Part I. These results are contained in papers [80] and [28]. In the second part of the thesis we focus on the concurrent setting, and we investigate on protocols achieving round optimality and black- box access to a cryptographic primitive. We study two fundamental functionalities: commitment scheme and zero knowledge, and we focus on some of the round-optimal constructions and lower bounds con- cerning both functionalities. We nd that such constructions present subtle issues. Hence, we provide new protocols that actually achieve the security guarantee promised by previous results. Concerning physical attacks, we consider adversaries able to re- set the machine of the honest party. In a reset attack a machine is forced to run a protocol several times using the same randomness. In this thesis we provide the rst construction of a witness indistinguish- able argument system that is simultaneous resettable and argument of knowledge. We discuss about this contribution in Part III, which is the content of the paper. [edited by Author]

Apurva Dargar

The security of electronic devices is of crucial importance to companies as well as to users.Moreover, companies that develop Intellectual Property also want to protect them from counterfeiting and overbuilding.Company profits, brand reputations and personal information of the users are at stake if there is a breach in the security of these electronic devices.In the classical approach, a system is secured by storing the cryptographic keys permanently in the non-volatile memories that are present in the security devices.However, this permanent storage of the key makes them easy targets for physical attacks; hence compromising the security of the system.A more secure, cost-effective and elegant solution to this permanent key storage is the use of Physical Unclonable Functions (PUFs).PUF is a method of producing a signature from a physical object, such as an Integrated Circuit, by relying on the non-reproducible physical attributes of a device.These signatures are unique because fabricated circuits exhibit slightly different electrical behavior from one another even if their design, mask and manufacturing process are identical.Various kinds of PUFs exist; examples are Optical PUF, Butterfly PUF and SRAM PUF.However, the start-up value based SRAM PUFs appear to be the most promising ones for usage in ICs.Although the SRAM PUFs are becoming very popular, only a little has been published in the field of modeling and analysis of their start-up behavior.Reproducing the same start-up behavior, every time the chip is powered-on, is very crucial in order to produce the same cryptographic key.This thesis proposes an analytical model for the start-up value based SRAM PUFs; it helps in understanding the impact of both non-technological parameters (such as supply voltage and temperature) as well as technological parameters (such as the geometry of the transistors and threshold voltage) on the behavior of the start-up values of an SRAM.Various experiments have been performed to analyze and quantify their impact.The results obtained indicate a major impact of the non-technology parameters.The reproducibility of start-up values becomes more likely with slower ramp-ups and lower temperatures.For example, the percentage of reproducible bits increase from 93.5% at 1s ramp-up to 96% at 10ms ramp-up.Amongst the technology parameters, it is observed that a small mismatch of 1.6% in the threshold voltage is enough to flip the start-up value of the cell for 65nm technology.These results have been validated by comparing them with actual silicon data measured at Intrinsic ID.The validation of the results proves the correctness of the analytical model proposed and gives a proof of robustness of the start-up values. Modeling SRAM Start-up Characteristics ForPhysical Unclonable Functions

Tobias Jeske

Smartmeters report the current electricity consumption over the internet back to their energy providers. Finely-sampled power consumption enables the energy provider to learn the habits of the customer's household in which the smart meter is installed. This paper presents a protocol which preserves customer privacy but also allows the detection of unregistered smart meters and prevents spamming and replay attacks. A trusted-third-party is not needed. This protocol, whose security proof relies on the strong RSA assumption and the random oracle model, is based on zero-knowledge techniques. The protocol has been implemented on different hardware platforms and benchmark results are given.