ABSTRACT The period from the mid-1990s to the mid-2000s saw the transformation of information and communication infrastructure. In the same period, TPRC evolved from a narrower focus on conventional telecommunications and information policy to âThe Research Conference on Communications, Information, and Internet Policy.â Through the lens of my own interdisciplinary work on Internet policy and intersecting TPRC activity, this retrospective describes an arc of change that began at the 1994 TPRC and continued for about a decade. It combines description, commentary, and reflections on what this history might bode for TPRC as metaverses and Web3 progress from todayâs hype to tomorrowâs Internet.
Pedro Antonino, Juliandson Ferreira, Augusto Sampaio, A. W. Roscoe
Smart contract evolution is crucial for the success of decentralized applications, and current methods and processes are not well suited to handle these drivers of change, as the knowledge about the software is predominantly stored in informal documents. In addition, they are the building blocks of the âcode is lawâ paradigm: the smart contractâs code indisputably describes how its assets are to be managed - once it is created, its code is typically immutable. Faulty smart contracts present the most significant evidence against the practicality of this paradigm; they are well-documented and resulted in assets worth vast sums of money being compromised. To address this issue, the Ethereum community proposed (i) tools and processes to audit/analyse smart contracts, and (ii) design patterns implementing a mechanism to make contract code mutable. Individually, (i) and (ii) only partially address the challenges raised by the âcode is lawâ paradigm. In this work, we combine elements from (i) and (ii) to create a systematic framework that moves away from âcode is lawâ and gives rise to a new âspecifica- tion is lawâ paradigm. It allows contracts to be created and upgraded but only if they meet a corresponding formal specification. We explain how formal verification techniques can be used to ensure safety properties of smart contracts during their evolution. Although formal verification methods have the potential of being used in several application fields, we focus on ensuring compliance with its specifications. The process consists of three phases: Formal requirements specification, verification, and deployment. All steps are planned and executed in an integrated way and together they form a framework capable of fostering safe evolution and make it more reliable and secure. The framework is centered around a trusted deployer: an off-chain service that formally verifies and enforces specification conformance. We have proto- typed this framework, and investigated its applicability to contracts implementing three widely used Ethereum standards: the ERC20 Token Standard, ERC3156 Flash Loans and ERC1155 Multi Token Standard, with promising results.
Xuechun Mao, Lin You, Chengtang Cao, Gengran Hu · 5 authors
Biometric encryption, especially based on fingerprint, plays an important role in privacy protection and identity authentication. In this paper, we construct a privacy-preserving linkable ring signature scheme. In our scheme, we utilize a fuzzy symmetric encryption scheme called symmetric keyring encryption (SKE) to hide the secret key and use non-interactive zero-knowledge (NIZK) protocol to ensure that we do not leak any information about the message. Unlike the blind signature, we use NIZK protocol to cancel the interaction between the signer (the prover) and the verifier. The security proof shows that our scheme is secure under the random oracle model. Finally, we implement it on a personal computer and analyze the performance of the constructed scheme in practical terms. Based on the constructed scheme and demo, we give an anonymous cryptocurrency transaction model as well as mobile demonstration.
Jan LĂĄnskĂœ, Amir Masoud Rahmani, Saqib Ali, Nasour Bagheri · 7 authors
In this paper, targeting efficient authentication and key agreement in an IoT environment, we propose an Elliptic Curve Cryptography-(ECC) based lightweight authentication protocol called BCmECC which relies on a public blockchain to validate the usersâ public key to provide desired security. We evaluate the security of the proposed protocol heuristically and validate it formally, which demonstratse the high level of the security. For the formal verification we used the widely accepted formal methods, i.e., BAN logic and the Scyther tool. In this paper we also analyse the security of recently proposed blockchain-based authentication protocols and show that this protocol does not provide the desired security against known session-specific temporary information attacks in which the adversary has access to the sessionâs ephemeral values and aims to retrieve the shared session key. In addition, the protocol lacks forward secrecy, in which an adversary with access to the serverâs long-term secret key can retrieve the previous session keys, assuming that the adversary has already eavesdropped the transferred messages over a public channel in the target session. The proposed attacks are very efficient and their success probability is â1â, while the time complexity of each attack could be negligible. Besides, we show that BCmECC is secure against such attacks.
âAlgebra is one of the important fields of mathematics. It concerns with the study and manipulation of mathematical symbols. It also concerns with the study of abstractions such as groups, rings, and fields. Due to the development of these abstractions, it is extended to consider other structures, such as vectors, matrices, and polynomials, which are non-numerical objects. Computer algebra is the implementation of algebraic methods as algorithms and computer programs. Recently, many algebraic cryptosystem protocols are based on non-commutative algebraic structures, such as authentication, key exchange, and encryptiondecryption processes are adopted. Cryptography is the science that aimed at sending the information through public channels in such a way that only an authorized recipient can read it. Ring theory is the most attractive category of algebra in the area of cryptography. In this paper, we employ the algebraic structure called skew -Armendariz rings to design a neoteric algorithm for zero knowledge proof. The proposed protocol is established and illustrated through numerical example, and its soundness and completeness are proved
Mustafa Kara, Muhammed Ali Aydın, Hasan H. Balık
Peer-to-peer VoIP applications are exposed to threats in the Internet environment as they carry out conversations over the Internet, which is an electronic communication line, and its security has always been largely a matter of concern. Authentication of the caller is the first line of defense among the security principles and is an important principle to provide security in VoIP application. Authentication methods in VoIP applications are usually based on trusted third parties or through centralized architecture. This situation creates problems in terms of single point of failure and privacy in call security over IP based communications. However, blockchain technology with a distributed architecture offers an innovative solution to multimedia communication authentication model. In this paper, a blockchain-based mutual authentication scheme for VoIP applications is proposed. In addition, the model's having a comprehensive security structure against various threats is explained via security and communication cost analysis. The proposed schema shows better performance than the methods that make a verification through the centralized architecture in the literature. The proposed model has been formally verified using the AVISPA tool, and it has been proven that the model is safe against potential threats.
The vast majority of communication on the Internet and private networks heavily relies on Public-key infrastructure (PKI). One possible solution, to avoid complexities around PKI, is to use Password Authenticated Key-Exchange (PAKE) protocols. PAKE protocols enable a secure communication link between the two parties who only share a low-entropy secret (password). PAKEs were introduced in the 1990s, and with the introduction of the first security models and security proofs in the early 2000s, it was clear that PAKEs have a potential for wide deployment - filling the gap where PKI falls short. PAKEsâ PKI-free nature, resistance to phishing attacks and forward secrecy are just some of the properties that make them interesting and important to study. This dissertation includes three works on various aspects of PAKEs: an attack on an existing PAKE proposal, an application of PAKEs in login (for password leak detection) and authentication protocols (HoneyPAKEs), and a security analysis of the J-PAKE protocol, that is used in practice, and its variants. In our first work, we provide an empirical analysis of the zkPAKE protocol proposed in 2015. Our findings show that zkPAKE is not safe against offline dictionary attacks, which is one of the basic security requirements of the PAKE protocols. Further, we demonstrate an implementation of an efficient offline dictionary attack, which emphasizes that, it is necessary to provide a rigorous security proof when proposing a new protocol. In our second contribution, we propose a combined security mechanism called HoneyPAKE. The HoneyPAKE construction aims to detect the loss of password files and ensures that PAKE intrinsically protects that password. This makes the PAKE part of the HoneyPAKE more resilient to server-compromise and pre-computation attacks which are a serious security threat in a client-server communication. Our third contribution facilitates the wider adoption of PAKEs. In this work, we revisit J-PAKE and simplify it by removing a non-interactive zero knowledge proof from the last round of the protocol and derive a lighter and more efficient version called sJ-PAKE. Furthermore, we prove sJ-PAKE secure in the indistinguishability game-based model, the so-called Real-or-Random, also satisfying the notion of perfect forward secrecy.
The vast majority of communication on the Internet and private networks heavily relies on Public-key infrastructure (PKI). One possible solution, to avoid complexities around PKI, is to use Password Authenticated Key-Exchange (PAKE) protocols. PAKE protocols enable a secure communication link between the two parties who only share a low-entropy secret (password). PAKEs were introduced in the 1990s, and with the introduction of the first security models and security proofs in the early 2000s, it was clear that PAKEs have a potential for wide deployment - filling the gap where PKI falls short. PAKEs' PKI-free nature, resistance to phishing attacks and forward secrecy are just some of the properties that make them interesting and important to study. This dissertation includes three works on various aspects of PAKEs: an attack on an existing PAKE proposal, an application of PAKEs in login (for password leak detection) and authentication protocols (HoneyPAKEs), and a security analysis of the J-PAKE protocol, that is used in practice, and its variants. In our first work, we provide an empirical analysis of the zkPAKE protocol proposed in 2015. Our findings show that zkPAKE is not safe against offline dictionary attacks, which is one of the basic security requirements of the PAKE protocols. Further, we demonstrate an implementation of an efficient offline dictionary attack, which emphasizes that, it is necessary to provide a rigorous security proof when proposing a new protocol. In our second contribution, we propose a combined security mechanism called HoneyPAKE. The HoneyPAKE construction aims to detect the loss of password files and ensures that PAKE intrinsically protects that password. This makes the PAKE part of the HoneyPAKE more resilient to server-compromise and pre-computation attacks which are a serious security threat in a client-server communication. Our third contribution facilitates the wider adoption of PAKEs. In this work, we revisit J-PAKE and simplify it by removing a non-interactive zero knowledge proof from the last round of the protocol and derive a lighter and more efficient version called sJ-PAKE. Furthermore, we prove sJ-PAKE secure in the indistinguishability game-based model, the so-called Real-or-Random, also satisfying the notion of perfect forward secrecy.
Zero-Knowledge proofs (ZKPs) enable proving of mathematical statements, revealing nothing but their validity. We design an authentication sys-tem with a ZKP as a password verification mech-anism within the Extensible Authentication Pro-tocol (EAP) framework. Designing a secure pass-word authentication system requires us to adopt security practices for protecting ourselves against the vulnerabilities of passwords. Integrating said practices is not trivial because of the tight cou-pling with the password verification method.
Intelligent transportation systems (ITS) have always been an important application of Internet of Things (IoT). Today, big data and cloud computing have further promoted the construction and development of ITS. At the same time, the development of blockchain has also brought new features and convenience to ITS. However, due to the endless emergence of increasingly advanced types of attacks, the security of blockchain-based ITS needs more attention from industry and academia. In this paper, we focus on exploring the primitives in cryptography to guarantee the security of blockchain-based ITS. In particular, the authentication, encryption, and key management schemes in cryptography are discussed. Furthermore, we propose two methods for achieving the threshold key management in blockchain-based ITS. The proposed threshold key management scheme (with threshold t ) enables various stakeholders to recover a secret if the number of participated stakeholders is at least t . It should be noted that the proposed threshold key management scheme is efficient and secure for multiple users in blockchain-based ITS, especially for the data-sharing scenario.
We describe a fast three-round mutual authentication protocol for parties A and B belonging to the same coalition group. Parties A and B keep their own independent long-term private keys that are used in the process of authentication and can be used for other purposes. The scheme assumes an initial setup with a trusted third party T. This party initiates another secret information that includes factors of a large RSA modulus. For authentication, both parties must demonstrate each other the knowledge of their private keys without revealing them and the ability to factorize a large RSA modulus. Thus, the protocol based on the suggested scheme provides reciprocal authentication. The scheme possesses all desirable properties of an interactive proof, i.e., completeness, soundness, and zero-knowledge. The security of the protocol relies on assumptions of difficulty of the RSA factorization and existence of a cryptographic hash function.
Josep LluĂs Ferrer Gomila, M. Francisca Hinarejos
Fair digital signature of contracts and agreements is an essential process in any electronic commerce scenario, and therefore also in data marketplaces, where the relationships and agreements among the different parties (consumers and providers) are more dynamic. In multi-party contract signing, N parties wish to sign a contract in a such a way that either all signatories obtain evidence of the signing or none obtains conflicting evidence regarding the honest signatories; the exchange must be fair. In this paper, we propose a blockchain-based multi-party contract signing protocol. This solution does not require the existence or potential intervention of a trusted third party (TTP), thus avoiding the difficulty of N signatories agreeing upon a TTP. In addition, this proposal meets the necessary requirements: fairness, timeliness, non-repudiation of origin, and non-repudiation of receipt. Furthermore, confidentiality can be easily achieved. To minimize costs associated with the use of blockchain, it should be invoked in the case of exception (analogous to optimistic solutions with a TTP) and by only one of the N signatories. However, when the use of blockchain is required, we show that its cost is within perfectly manageable margins.
In a seminal work, Goldreich, Micali and Wigderson (CRYPTO â86) demonstrated the wide applicability of zero-knowledge proofs by constructing such a proof system for the NP-complete problem of graph 3-coloring. A long-standing open question has been whether parallel repetition of their protocol preserves zero knowledge. In this work, we answer this question in the negative, assuming a standard cryptographic assumption (i.e., the hardness of learning with errors (LWE)).
Zero-knowledge proofs allow a prover to convince a verifier of the veracity of a statement without revealing any other information. An interesting class of zero-knowledge protocols are those following the MPC-in-the-head paradigm (Ishai et al., STOC '07) which use secure multiparty computation (MPC) protocols as the basis. Efficient instances of this paradigm have emerged as an active research topic in the last years, starting with ZKBoo (Giacomelli et al., USENIX '16). Zero-knowledge protocols are a vital building block in the design of privacy-preserving technologies as well as cryptographic primitives like digital signature schemes that provide post-quantum security. This work investigates the security of zero-knowledge protocols following the MPC-in-the-head paradigm. We provide the first machine-checked security proof of such a protocol on the example of ZKBoo. Our proofs are checked in the EasyCrypt proof assistant. To enable a modular security proof, we develop a new security notion for the MPC protocols used in MPC-in-the-head zero-knowledge protocols. This allows us to recast existing security proofs in a black-box fashion which we believe to be of independent interest.
Tobacco products are an addictive commodity. According to the World Health Organizationâs (WHO) latest statistics data, tobacco kills more than eight million people each year. In 2003, the WHO proposed the Framework Convention on Tobacco Control (FCTC) to provide an effective framework for the control of tobacco products to governments around the world. In the field of tobacco products, the hardest problem is how to prevent counterfeit tobacco products and smuggling. To solve the problems, we proposed a blockchain-based traceable and verifiable logistics system for tobacco products with global positioning system (GPS) and radio-frequency identification (RFID) Technologies. In this research, we provide an overview of system architecture, and also define the protocol and the smart contract in every phase that stores data into the blockchain center. We realized a decentralized database and authentication system that uses blockchain and smart contract technology; every protocol in every phase was designed to achieve the integrity of data and non-repudiation of message. Every tobacco productâs shipping record will be completed by scanning the RFID tag and retrieving the GPS with a mobile reader, where the record will be updated and validated in the blockchain center. In the end, the security and costs of the system were analyzed, and a comparison was made with the EUâs (European Commission) method. Our system is more flexible for transportation, more secure in the communication protocol, and more difficult to tamper and forge data. In general, the proposed scheme solved the problem of tobacco products counterfeiting and tracking issues.
Miqi Wu, Lin You, Gengran Hu, Liang Li · 5 authors
In a multiserver architecture, authentication schemes play an important role in the secure communication of the system. In many multiserver authentication schemes, the security of the mutual authentications among the participants is based on the security of the registration centerâs private key. This centralized architecture can create security risks due to the leakage of the registration centerâs private key. Blockchain technology, with its decentralized, tamper-proof, and distributed features, can provide a new solution for multiserver authentication schemes. In a lot of multiserver authentication schemes, usersâ permission is generally controlled by the registration center (RC), but these permission control methods cannot be applied in the decentralized blockchain system. In this paper, a blockchain-based authentication scheme for multiserver architecture is proposed. Our scheme provides a hierarchical authentication method to solve the problems of user permission control and user revocation caused by no registration center. The security of our scheme is formally proved under the random oracle model. According to our analysis, our scheme is resistant to attacks such as impersonation attacks and man-in-the-middle attacks. In addition, our performance analysis shows that the proposed scheme has less computation overhead.
AdriĂĄn Silveira, Gustavo Betarte, Maximiliano CristiĂĄ, Carlos Luna
MimbleWimble (MW) is a privacy-oriented cryptocurrency technology which provides security and scalability properties that distinguish it from other protocols of its kind. We present and discuss those properties and outline the basis of a model-driven verification approach to address the certification of the correctness of the protocol implementations. In particular, we propose an idealized model that is key in the described verification process, and identify and precisely state sufficient conditions for our model to ensure the verification of relevant security properties of MW. Since MW is built on top of a consensus protocol, we develop a Z specification of one such protocol and present an excerpt of the $\{log\}$ prototype generated from the Z specification. This $\{log\}$ prototype can be used as an executable model where simulations can be run. This allows us to analyze the behavior of the protocol without having to implement it in a low level programming language. Finally, we analyze the Grin and Beam implementations of MW in their current state of development.
Mit Bitcoin wurde 2008 die erste KryptowĂ€hrung veröffentlicht. Mit ihr können Zahlungen getĂ€tigt werden, ohne einer zentralen Stelle wie einer Bank vertrauen zu mĂŒssen. Dies wird durch einen innovativen Konsensus-Mechanismus ermöglicht, der unter der Bezeichnung Proof-of-Work bekannt ist. Bitcoin ist noch immer die bekannteste und wertvollste KryptowĂ€hrung. Ăber die Jahre sind jedoch einige Probleme offenkundig geworden, wie z.B. der hohe Energieverbrauch und der niedriger Transaktionsdurchsatz. Um das Jahr 2016 kam eine neue Art von Protokollen auf, welche versprach diese beiden Probleme gleichzeitig zu lösen. Diese Protokolle basieren auf dem Proof-of-Stake (PoS) Mechanismus und verwenden gerichtete azyklische Graphen als Datenstruktur. Da es sich hier ebenfalls um WĂ€hrungen handelt, spielt Sicherheit eine zentrale Rolle. Dies wirft die Frage auf, wie sicher Protokolle dieser Art wirklich sind. Diese Arbeit trĂ€gt zur Beantwortung bei, indem Hashgraph im Detail analysiert wird. Hashgraph ist ein vielversprechender Vertreter dieser Protokollart. Die verschiedensten Sicherheits- und Performanceangaben des Protokolls werden mithilfen eines im Zuge der Arbeit entwickelten und veröffentlichten Simulators ĂŒberprĂŒft. Der Simulator ermöglicht es, das Verhalten des Protokolls unter vier verschiedenen (Angriffs-)Szenarien zu untersuchen. Er bietet dazu umfangreiche Konfigurationsmöglichkeiten an, welche unzĂ€hlige verschiedene VerlĂ€ufe ermöglichen. Akteure/Akteurinnen agieren zufĂ€llig basierend auf einem verĂ€nderbaren Parameter, der Reproduzierbarkeit gewĂ€hrleistet. Der Simulator selbst verfĂŒgt auĂerdem ĂŒber eine grafische BenutzerobeflĂ€che, wobei Ergebnisse auch als Text-Dateien fĂŒr weitere Analysen exportiert werden können. In keiner einzigen von tausenden Simulationen wurde der Konsensus-Mechanismus von Hashgraph gebrochen. Basierend auf der Tatsache das Nachrichten zur Synchronsiation beliebig schnell und an beliebige andere Knoten gesendet werden können, kamen jedoch Schwachstellen zu Tage. Diese Arbeit zeigt auf, dass es möglich ist eine widersprĂŒchliche Transaktion zu einer bereits existierenden zu veröffentlichen und diese schneller bestĂ€tigt zu bekommen. Weiters wird belohnt, wer Synchronisationen zuerst mit ganz bestimmten Knoten durchfĂŒhrt, was zu einer Ăberlastung dieser Knoten fĂŒhren kann. Die prĂ€sentierten Ergebnisse zeigen, dass diese Protokollklasse tatsĂ€chlich das Potential besitzt, zwei der grundelegenden Probleme von traditionellen KryptowĂ€hrungen zu lösen. Die Möglichkeit von Nachrichten-Spam im System kann dies jedoch zunichte machen und ist ein wichtiger Punkt in der Bewertung solcher Protokolle.
Ayman Alkhalifah, Alex Ng, Paul Watters, A. S. M. Kayes
In Ethereum blockchain, smart contracts are immutable, public, and distributed. However, they are subject to many vulnerabilities stemming from coding errors made by developers. Seven cybersecurity incidents occurred in Ethereum smart contracts between 2016 and 2018, which led to financial losses estimated to be over US$ 289 million. Reentrancy vulnerability was the cause of two of these incidents, and the impacts went far beyond financial loss. Several reentrancy countermeasures are available, which are based on predefined patterns that are used to prevent vulnerability exploitation before the deployment of a smart contract; however, several limitations have been identified in these countermeasures. Motivated by all these issues, the objective of this article is to help developers improve the cybersecurity of smart contracts by proposing a solution that calculates the difference between the contract balance and the total balance of all participants in a smart contract before and after any operation in a transaction that changes its state. Proof-of-concept implementations show that this solution can provide a detection and prevention mechanism against reentrancy attacks during the execution of any smart contract.
The fifth generation (5G) cellular network provides users with high-quality services due to its high transmission rate and low latency. It will support Internet of Things (IoT) devices and enable new applications in health, banking, education, etc. Security is essential in this network because vulnerabilities may be exploited to disrupt these applications which may directly impact our life. Authentication and key agreement (AKA) and handover (HO) are usually the target of cyberattacks in any cellular network. On the other hand, blockchain is a peer-to-peer network that aims to maintain an immutable and secure ledger. This new technology will be used widely to secure many applications. This paper aims to develop an efficient and secure AKA scheme and uniform handover protocol for 5G network using blockchain. The home network (HN) is not involved in the AKA scheme and HO protocol to protect the HN from attacks, such as denial of service (DoS) attacks, and also lower the communication and computation overhead. Moreover, our HO protocol is uniform in the sense that it can be used for all HO scenarios. The protocol is also efficient because it requires exchanging a few amount of data. It can also achieve forward/backward secrecy. Furthermore, the blockchain is used to verify the public keys of the network nodes which is necessary to secure our AKA scheme and HO protocol. It also records the locations of the users which is necessary for the functionality of the network. Our evaluations demonstrate that the proposed HO protocol is secure, uniform, and can achieve the forward/backward secrecy. Furthermore, our AKA scheme requires lower computation and computation overhead comparing to the existing schemes, and preserves the energy of the limited-energy mobile devices.
Tarik Hidar, Anas Abou El Kalam, Siham Benhadou, Oussama Mounnan
Since the Tactile Internet has been considered as a new era of Internet, delivering real-time interactive systems as well as ultra-reliable and ultra-responsive network connectivity, tremendous efforts have been made to ensure authentication between communicationâs parties to secure remote surgery. Since this human to machine interaction like remote surgery is critical and the communication between the surgeon and the tactile actor i.e. robot arms should be fully protected during the surgical procedure, a fully secure mutual user authentication scheme should be used in order to establish a secure session among the communicating parties. The existing methods usually require a server to ensure the authentication among the communicating parties, which makes the system vulnerable to single of point failure and not fit the design of such critical distributed environment i.e. tactile internet. To address these issues, we propose a new decentralized blockchain based authentication solution for tactile internet. In our proposed solution, there is no need for a trusted party; moreover, the decentralized nature of our proposed solution makes the authentication immutable, efficient, secure, and low latency requirement. The implementation of our proposed solution is deployed on Ethereum official test network Ropsten. The experimental results show that our solution is efficient, highly secured, and flexible.
Abstract It is well known that several cryptographic primitives cannot be achieved without a common reference string (CRS). Those include, for instance, non-interactive zero-knowledge for NP, or maliciously secure computation in fewer than four rounds. The security of those primitives heavily relies on the assumption that the trusted authority, who generates the CRS, does not misuse the randomness used in the CRS generation. However, we argue that there is no such thing as an unconditionally trusted authority and every authority must be held accountable for any trust to be well-founded. Indeed, a malicious authority can, for instance, recover private inputs of honest parties given transcripts of the protocols executed with respect to the CRS it has generated. While eliminating trust in the trusted authority may not be entirely feasible, can we at least move towards achieving some notion of accountability? We propose a new notion in which, if the CRS authority releases the private inputs of protocol executions to others, we can then provide a publicly-verifiable proof that certifies that the authority misbehaved. We study the feasibility of this notion in the context of non-interactive zero knowledge and two-round secure two-party computation.