Mahmoud El-Gayyar, Hany F. ElYamany, Katarina Grolinger, Miriam A. M. Capretz · 5 authors
A federated identity is a single identity that enables users to access multiple services across a network of business parties. Such identities are subject to various threats and attacks and face diverse challenges including identity leaks, centralised management, auditing limitations, and long breach investigation processes. This paper proposes a framework aimed at automating and decentralising the generation and auditing of a robust and secured blockchain-based federated identity in a marketplace. Business parties participating in the marketplace form the nodes of a distributed blockchain network and participate in the creation of federated identities. Users of this network can access services provided by any one of the participating parties using a single federated identity. All transactions are fully audited in the blockchain, meaning that participating parties can monitor access to their service and users can trace the use of their identities. The proposed framework has been evaluated using two blockchain technologies (Ethereum and Hyperledger Fabric) to measure its performance in public and permissioned blockchain environments.
A blockchain-enabled online-voting system is being proposed in this following paper. Blockchain technologies deliver an endless variety of applications that benefit from distributed economies. The proposed model is an android application that has enhanced security features which includes both authentication and authorization. Authentication is incorporated by using a unique identification key and authorization is done by using fingerprint. Voters are also being verified by One-time password. The security in this project is implemented by using a 128 bit AES encryption algorithm and SHA-256 along with blockchain. The vote is casted in the form of transaction, where a blockchain is created, which keeps track of tallies of votes. Through this atomicity and integrity are maintained. [4] Index Terms—Voting System , Blockchain , SHA-256, Security, AES-128, Ballot
Open access
Internet Traffic Analysis and Secure E-voting
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Verifiable mix nets, and specifically proofs of (correct) shuffle, are a fundamental building block in numerous applications: these zero-knowledge proofs allow the prover to produce a public transcript which can be perused by the verifier to confirm the purported shuffle. They are particularly vital to verifiable electronic voting, where they underpin almost all voting schemes with non-trivial tallying methods. These complicated pieces of cryptography are a prime location for critical errors which might allow undetected modification of the outcome.The best solution to preventing these errors is to machine-check the cryptographic properties of the design and implementation of the mix net. Particularly crucial for the integrity of the outcome is the soundness of the design and implementation of the verifier (software). Unfortunately, several different encryption schemes are used in many different slight variations which makes it infeasible to machine-check every single case individually. However, a particular optimised variant of the Terelius-Wikström mix net is, and has been, widely deployed in elections including national elections in Norway, Estonia and Switzerland, albeit with many slight variations and several different encryption schemes.In this work, we develop the logical theory and formal methods tools to machine-check the design and implementation of all these variants of Terelius-Wikström mix nets, for all the different encryption schemes used; resulting in provably correct mix nets for all these different variations. We do this carefully to ensure that we can extract a formally verified implementation of the verifier (software) which is compatible with existing deployed implementations of the Terelius-Wikström mix net. This gives us provably correct implementations of the verifiers for more than half of the national elections which have used verifiable mix nets.Our implementation of a proof of correct shuffle is the first to be machine-checked to be cryptographically correct and able to verify proof transcripts from national elections. We demonstrate the practicality of our implementation by verifying transcripts produced by the Verificatum mix net system and the CHVote e-voting system from Switzerland.
Over the past twenty years, the number of devices connected to the Internet grew exponentially. Botnets benefited from this rise to increase their size and the magnitude of their attacks. However, they still have a weak point in their Command & Control (C&C) system, which is often based on centralized services or require a complex infrastructure to keep operating without being taken down by authorities. The recent spread of blockchain technologies may give botnets a powerful tool to make them very hard to disrupt. Recent research showed how it is possible to embed C&C messages in Bitcoin transactions, making them nearly impossible to block. Nevertheless, transactions have a cost and allow very limited amounts of data to be transmitted. Because of that, only messages from the botmaster to the bots are sent via Bitcoin, while bots are assumed to communicate through external channels. Furthermore, for the same reason, Bitcoin-based messages are sent in clear. In this paper we show how, using Bitcoin Testnet, it is possible to overcome these limitations and implement a cost-free, bidirectional, and encrypted C&C channel between the botmaster and the bots. We propose a communication protocol and analyze its viability in real life. Our results show that this approach would enable a botmaster to build a robust and hard-to-disrupt C&C system at virtually no cost, thus representing a realistic threat for which countermeasures should be devised.
Utz Nisslmueller, Klaus-Tycho Foerster, Stefan Schmid, Christian Decker
Cryptocurrency off-chain networks such as Lightning (e.g., Bitcoin) or Raiden (e.g., Ethereum) aim to increase the scalability of traditional on-chain transactions. To support nodes in learning about possible paths to route their transactions, these networks need to provide gossip and probing mechanisms. This paper explores whether these mechanisms may be exploited to infer sensitive information about the flow of transactions, and eventually harm privacy. In particular, we identify two threats, related to an active and a passive adversary. The first is a probing attack: here the adversary aims to detect the maximum amount which is transferable in a given direction over a target channel by actively probing it and differentiating the response messages it receives. The second is a timing attack: the adversary discovers how close the destination of a routed payment actually is, by acting as a passive man-in-the middle and analyzing the time deltas between sent messages and their corresponding responses. We then analyze the limitations of these attacks and propose remediations for scenarios in which they are able to produce accurate results.
The concept of coin mixing is significant in blockchain and achieves anonymity and has merited application in bitcoin. Albeit, several coin mixing schemes have been proposed, we point out that they either hoard input transactions and address mapping or not fully satisfy all requirements of practical anonymity. This paper proposes a coin mixing scheme (mixing countersignature scheme, ring signature, and coin mixing approach) that allows users to transact business untraceably and unlinkably without having to trust a third party to ensure coins are safe. Our proposed novel countersignature scheme simulation results prove the countersignature scheme's correctness with an average running time of 4 μs using PBC type A.80. The scheme's security and privacy are met with standard ring signature, ECDSA unforgeability and our countersignature. We demonstrated the efficiency of the mixing scheme using bitcoin's core regtest mode to set up a private bitcoin network. The mix takes 80, 160, 320, 640, 800 secs to service 500, 1,000, 2,000, 4,000, 5,000 users respectively. It was observed that the number of users scales linearly with average running time.
2 source records
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
E-voting is the process of conducting the voting process through online. The voters can cast their votes from different locations and these votes are collected and recorded electronically. Therefore, there is a need for a system to provide control and security to the whole procedure. Blockchain, a distributed ledger technology can be integrated to provide a decentralized system. Blockchain uses distributed ledger technology (DLT) to avoid forged voting option & non-repudiation and one time login of the user is also ensured. By integrating the above techniques, a secure user authentication for e-voting supported blockchain in p2p network is projected. This system would increase the safety by avoiding the forgery of votes. Similarly, the blockchain are often integrated to a spread of voting situations and a few alternative applications.
Open access
2 source records
Blockchain Technology Applications and Security
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
Zongyang Zhang, Weihan Li, Haitao Liu, Jianwei Liu
With the continuous development and popularity of blockchain technology, anonymity of cryptocurrency has attracted wide attention. Zcash is an altcoin of Bitcoin aiming to protect blockchain anonymity. Its anonymity is highly guaranteed by zero-knowledge proofs. However, it is still practicable to decrease Zcash's anonymity. In this paper, we provide a refined empirical analysis of Zcash anonymity. We improve current address clustering methods and increase the clustering rate by 9%. We also analyze the whole process of distributing mining reward and identify 87.5% addresses and 25.7% transactions. Besides, we simplify Zcash transaction network and then pick out nodes (edges) which play important roles in network connectivity. We show that these nodes are mostly mining pools. In particular, users participating in shieldedpool are mostly founders, miners and mining pools, although shieldedpool itself is designed for protecting anonymity of users with high privacy requirements. Our results, to an extent, are opposite to the original intention of Zcash.
Anita A. Lahane, Junaid Patel, Talif Pathan, Prathmesh Potdar
Election could be a important event during a trendy democracy however massive sections of society round the world don’t trust their election system that is major concern for the democracy. Even the world’s largest democracies like Republic of India, us, and Japan still suffer from a blemished legal system. Vote rigging, hacking of the EVM (Electronic vote machine), election manipulation, and booth capturing square measure the key problems within the current electoral system. during this system, we tend to square measure work the problems|the problems within the election vote systems and attempting to propose the E-voting model which might resolve these issues. The system can highlight a number of the popular blockchain frameworks that provide blockchain as a service and associated electronic E-voting system that is predicated on blockchain that addresses all limitations severally, it additionally preserve participant’s obscurity whereas still being hospitable public examination. Building Associate in Nursing electronic electoral system that satisfies the legal necessities of legislators has been a challenge for an extended time. Distributed ledger technologies is Associate in Nursing exciting technological advancement within the info technology world. Blockchain technologies supply Associate in Nursing infinite vary of applications cashing in on sharing economies. Blockchain could be a unquiet technology of current era and guarantees to enhance the resilience of e-voting systems. this technique presents a shot to leverage edges of blockchain like cryptological foundations and transparency to attain an efficient theme for e-voting. The projected theme conforms to the elemental necessities for e-voting schemes and achieves end-to-end verifiability. The system presents in-depth analysis of the theme that with success demonstrates its effectiveness to attain Associate in Nursing end-to-end verifiable e-voting theme.
Open access
Internet Traffic Analysis and Secure E-voting
Network Security and Intrusion Detection
Advanced Steganography and Watermarking Techniques
Ben Kreuter, Tancrède Lepoint, Michele Orrù, Mariana Raykova
We present a cryptographic construction for anonymous tokens with private metadata bit, called PMBTokens. This primitive enables an issuer to provide a user with a lightweight, single-use anonymous trust token that can embed a single private bit, which is accessible only to the party who holds the secret authority key and is private with respect to anyone else. Our construction generalizes and extends the functionality of Privacy Pass (PETS’18) with this private metadata bit capability. It provides unforgeability, unlinkability, and privacy for the metadata bit properties based on the DDH and CTDH assumptions in the random oracle model. Both Privacy Pass and PMBTokens rely on non-interactive zero-knowledge proofs (NIZKs). We present new techniques to remove the need for NIZKs, while still achieving unlinkability. We implement our constructions and we report their efficiency costs.