PROOF OF LUCK: AN EFFICIENT BLOCKCHAIN CONSENSUS PROTOCOL

Download here : Proof of Luck: an Efficient Blockchain Consensus Protocol

Source : https://arxiv.org/pdf/1703.05435.pdf

Extract from Abstract

In the paper, we present designs for multiple blockchain consensus primitives and a novel blockchain system, all based on the use of trusted execution environments (TEEs), such as Intel SGX-enabled CPUs. First, we show how using TEEs for existing proof of work schemes can make mining equitably distributed by preventing the use of ASICs. Next, we extend the design with proof of time and proof of ownership consensus primitives to make mining energy- and time-efficient. Further improving on these designs, we present a blockchain using a proof of luck consensus protocol. Our proof of luck blockchain uses a TEE platform's random number generation to choose a consensus leader, which offers low-latency transaction validation, deterministic confirmation time, negligible energy consumption, and equitably distributed mining. Lastly, we discuss a potential protection against up to a constant number of compromised TEEs.

Author Details

Mitar Milutinovic,UC Berkeley,mitar@cs.berkeley.edu
Warren He ,UC Berkeley,-w@berkeley.edu
Howard Wu,UC Berkeley,howardwu@berkeley.edu

LELANTOS: A BLOCKCHAIN-BASED ANONYMOUS PHYSICAL DELIVERY SYSTEM

Download here : Lelantos: A Blockchain-based Anonymous Physical Delivery System

Source : https://eprint.iacr.org/2017/465.pdf

Extract from Abstract

Real  world  physical  shopping  offers  customers  the privilege of maintaining their privacy by giving them the option of  using  cash,  and  thus  providing  no  personal  information such  as  their  names  and  home  addresses.  On  the  contrary,electronic  shopping  mandates  the  use  of  all  sorts  of  personally identifiable information for both billing and shipping purposes. Cryptocurrencies  such  as  Bitcoin  have  created  a  stimulated growth  in  private  billing  by  enabling  pseudonymous  payments. However, the anonymous delivery of the purchased physical goods is still an open research problem.

In  this  work,  we  present  a  blockchain-based  physical  delivery  system  called Lelantos that  within  a  realistic  threat model, offers customer anonymity, fair exchange and merchant customer  unlinkability.  Our  system  is  inspired  by  the  onion routing techniques which are used to achieve anonymous message delivery. Additionally, Lelantos relies on the decentralization and pseudonymity of the blockchain to enable pseudonymity that is hard to compromise, and the distributed consensus mechanisms provided by smart contracts to enforce fair irrefutable transactions between distrustful contractual parties.

Author Details

Riham AlTawy,Muhammad ElSheikh,Amr M. Youssef and Guang Gong
Electrical and Computer Engineering Department, University of Waterloo, Ontario, Canada.
Concordia Institute for Information Systems Engineering, Concordia University, Quebec, Canada

BLOCKCHAIN: A DISTRIBUTED SOLUTION TO AUTOMOTIVE SECURITY AND PRIVACY

Download here : Blockchain: A distributed solution to Automotive Security and Privacy

Source : https://arxiv.org/abs/1704.00073

Extract from Abstract

Interconnected smart vehicles offer a range of sophisticated services that benefit the vehicle owners, transport authorities, car manufacturers and other service providers. This potentially exposes smart vehicles to a range of security and privacy threats such as location tracking or remote hijacking of the vehicle. In this article, we argue that BlockChain (BC), a disruptive technology that has found many applications from cryptocurrencies to smart contracts, is a potential solution to these challenges. We propose a BC-based architecture to protect the privacy of the users and to increase the security of the vehicular ecosystem. Wireless remote software updates and other emerging services such as dynamic vehicle insurance fees, are used to illustrate the efficacy of the proposed security architecture. We also qualitatively argue the resilience of the architecture against common security attacks.

Author Details

Ali Dorri, Marco Steger,Salil S. Kanhere, and Raja Jurdak

This paper is accepted to be published in IEEE Communications Magazine and is subjected to IEEE copyright.

A TRACEABILITY ANALYSIS OF MONERO’S BLOCKCHAIN

Download here : A Traceability Analysis of Monero’s Blockchain

Source : https://eprint.iacr.org/2017/338.pdf

Extract from Abstract

Monero is a cryptocurrency that has rapidly gained popularity since its launch in April 2014. The source of its growth can be mainly attributed to its unique privacy properties that go well beyond the pseudonymity property of cryptocurrencies such as Bitcoin.In this work, we conduct a forensic analysis of the Monero blockchain. Our main goal is to investigate Monero’s untraceability guarantee, which essentially means that given a transaction input,the real output being redeemed in it should be anonymous among a set of other outputs. To this end, we develop three heuristics that lead to simple-to-implement attack routines. We evaluate our attacks on the Monero blockchain and show that in 87% of cases, the real output being redeemed can be easily identfi ed with certainty. Moreover, we have compelling evidence that two of our attacks also extend to Monero RingCTs — the second generation Monero that even hides the transaction value.

Author Details

Amrit Kumar
National University of Singapore
amrit@comp.nus.edu.sg

Clément Fischer
National University of Singapore
cfischer@comp.nus.edu.sg

2-HOP BLOCKCHAIN:COMBINING PROOF-OF-WORK AND PROOF-OF-STAKE SECURELY

Download here : 2-hop Blockchain:Combining Proof-of-Work and Proof-of-Stake Securely

Source : https://eprint.iacr.org/2016/716.pdf

Extract from Abstract

Cryptocurrencies like Bitcoin have proven to be a phenomenal success.  Bitcoin-like systems use proof-of-work mechanism, and their security holds if the majority of the computing power is under the control of honest players. However, this assumption has been seriously challenged recently and Bitcoin-like systems will fail when this assumption is broken.We propose the first provably secure 2-hop blockchain by combining proof-of-work and proof-of-stake mechanisms.  On top of Bitcoin’s brilliant ideas of utilizing the power of the honest miners, via their computing resources, to secure the blockchain, we further leverage the power of the honest users/stakeholders, via their coins/stake, to achieve this goal. The security of our blockchain holds if the honest players control majority of the collective resources (which consists of both computing power and stake).That said, even if the adversary controls more than 50% computing power, the honest players still have the chance to defend the blockchain via honest stake

Author Details

Tuyet Duong,Lei Fan and Hong-Sheng Zhou
available at duongtt3@vcu.edu,fanlei@sjtu.edu.cn
and hszhou@vcu.edu

P2P MIXING AND UNLINKABLE BITCOIN TRANSACTIONS

Download here : P2P Mixing and Unlinkable Bitcoin Transactions

Source : https://eprint.iacr.org/2016/824.pdf

Extract from Abstract

Starting   with   Dining   Cryptographers   networks (DC-net),  several  peer-to-peer  (P2P)  anonymous  communication protocols  have  been  proposed. Despite  their  strong  anonymity guarantees   none   of   those   has   been employed   in   practice   so far:  Most  fail  to  simultaneously  handle  the  crucial  problems of  slot  collisions  and  malicious  peers,  while  the  remaining  ones handle those with a significant increased latency (communication rounds)  linear  in  the  number  of  participating  peers  in  the  best case,  and quadratic in  the  worst  case.  We  conceptualize  these P2P  anonymous  communication  protocols  as P2P  mixing ,  and present a novel P2P mixing protocol, DiceMix, that only requires constant  (i.e.,  four)  communication  rounds  in  the  best  case,  and 4 + 2 rounds  in  the  worst  case  of malicious  peers.  As  every individual malicious peer can prevent a protocol run from success by  omitting  his  messages,  we  find  DiceMix  with  its  worst-case linear-round  complexity  to  be  an  optimal  P2P  mixing  solution.

Author Details

Tim Ruffing
CISPA, Saarland University
tim.ruffing@mmci.uni-saarland.de

Pedro Moreno-Sanchez
Purdue University
pmorenos@purdue.edu

Aniket Kate
Purdue University
aniket@purdue.edu

MIXCOIN : ANONYMITY FOR BITCOIN WITH ACCOUNTABLE MIXES

Download here : Mixcoin :Anonymity for Bitcoin with accountable mixes

Source : https://eprint.iacr.org/2014/077.pdf

Extract from Abstract

We propose Mixcoin, a protocol to facilitate anonymous payments in Bitcoin and similar cryptocurrencies. We build on the emergent phenomenon of currency mixes, adding an accountability mechanism to expose theft. We demonstrate that incentives of mixes and clients can be  aligned  to  ensure  that  rational  mixes  will  not  steal.  Our  scheme  is efficient and fully compatible with Bitcoin. Against a passive attacker,our  scheme  provides  an  anonymity  set  of all other  users  mixing  coins contemporaneously.  This  is  an  interesting  new  property  with  no  clear analog in better-studied communication mixes. Against active attackers our scheme offers similar anonymity to traditional communication mixes.

Author Details

Joseph Bonneau,Arvind Narayanan,Andrew Miller,Jeremy Clark,Joshua A. Kroll and Edward W. Felten