We present the Balance Attack that can lead an adversary to double spend coins in proof-of-work blockchains. The Balance Attack bridges the gap between attacks that require to partition the network and attacks that require high mining power as it shows that one needs less mining power if it can delay network messages longer. We show that the attack succeeds with high probability even when the adversary has a less than half of the mining power. We also analyze theoretically the probability of success of the attack depending on the (i) difficulty of the crypto-puzzle that the proof-of-work solves, (ii) the network delay that the attacker introduces and (iii) the mining power of the attacker.
As an alternative to the energy greedy proof-of-work, new blockchains constrain the set of participants whose selection is debatable. These blockchains typically allow a fixed consortium of machines to decide upon new transaction blocks. In this paper, we introduce the community blockchain that bridges the gap between these public blockchains and constrained blockchains. The idea is to allow potentially all participants to decide upon “some” block while restricting the set of participants deciding upon “one” block. We also propose an implementation called ComChain that builds upon the Red Belly Blockchain, the fastest blockchain we are aware of. It runs a consensus among the existing community to elect a new community. This reconfiguration speeds up as the number of removed nodes increases.
Blockchain is an emerging technology for decentralized and transactional data sharing across a large network of untrusted participants. It enables new forms of distributed software architectures, where components can find agreements on their shared states without trusting a central integration point or any particular participating components. Considering the blockchain as a software connector helps make explicitly important architectural considerations on the resulting performance and quality attributes (for example, security, privacy, scalability and sustainability) of the system. Based on our experience in several projects using blockchain, in this paper we provide rationales to support the architectural decision on whether to employ a decentralized blockchain as opposed to other software solutions, like traditional shared data storage. Additionally, we explore specific implications of using the blockchain as a software connector including design trade-offs regarding quality attributes..
انتباه. هناك خطر من أن الأعضاء الذين لم يتم التحقق منهم ليسوا أعضاء في الفريق
Red Belly is difficult project to rate as it is still in stealth mode and key aspects of the project are still to be confirmed. Clearly, the hard cap, token metrics, and the development roadmap need to be disclosed in addition to a detailed explanation of the network’s token utility before we can try to fully evaluate the project.Despite this, there are some obvious strong points that highlight that Red Belly may be something special, such as the team having strong academic and business backgrounds that give the project a significant amount of credibility and hint that they may overcome the serious obstacle of ensuring platform adoption.Data61 has entered into a partnership with law firm Herbert Smith Freehills and IBM to build the Australian National Blockchain (ANB) project, and has also partnered with the Commonwealth Bank of Australia to pilot a blockchain-based smart money app. This highlights that the team are able to achieve significant results in the world of business and commerce, and are able to successfully leverage their extensive network and contacts from the University of Sydney and CSIRO.The project appears to be well positioned to establish itself in Australia however, the ANB project does throw up some issues as the service will be built on the IBM Blockchain and the previous test results announced by the team were obtained while using Amazon’s Web Services (AWS) global cloud infrastructure. As a result, many of the claims made by the team are still to be verified and public versions of their blockchain need to be evaluated by the general body of blockchain developers and programmers. In addition, we still need to see just what their blockchain can do “out in the wild” under more natural conditions.As a secure, high throughput, unforkable blockchain, Red Belly faces competition from established projects such as Ethereum and Stellar as well as from a large body of newer projects such as EOS and Hedera Hashgraph. In order to finally rate the project, we will need to see the overall metrics as well as delve deeper into the technical aspects of the project. For now, Red Belly remains one to keep an eye on and definitely has the potential to become an outstanding project.
يستند هذا العرض إلى المعلومات المقدمة فقط من قبل العارض ومعلومات أخرى متاحة للعموم. إن حدث بيع أو تبادل الرمز المميز لا علاقة له بكامله تجاه أصحاب الحيازات الدولية، ولا يمتلك أصحاب الحيازة أي مشاركة فيه (بما في ذلك أي دعم تقني أو ترويج). وتظهر مبيعات الرمز المميز المدرجة من الأشخاص الذين ليس لديهم علاقة بين أصحاب الحيازة فقط لمساعدة العملاء على تتبع النشاط الجاري في قطاع الرمز المميز العام. وليس المقصود من هذه المعلومات أن تصل إلى المشورة التي يجب أن تعتمد. يجب عليك الحصول على المشورة المهنية أو المتخصصة أو تنفيذ العناية الواجبة الخاصة بك قبل اتخاذ أو الامتناع عن أي إجراء على أساس المحتوى على موقعنا. إن أي شروط وأحكام يتم الدخول فيها من قبل المساهمين فيما يتعلق باقتناء الرموز المميزة هي بينهم وبين مصدر الرمز ومالك الشركة ليس البائع لهذه الرموز. لا يتحمل صاحب المشروع أية مسؤولية قانونية عن أية بيانات مقدمة من أطراف ثالثة فيما يتعلق بأي بيع رمزية وأي مطالبة عن خرق العقد يجب أن يتم أيضا مباشرة ضد الكيان المصدر للإصدار المميز المذكور هنا.
إذا كانت لديك أي مخاوف بشأن طبيعة أو خصوصية أو قانونية هذا البيع المميز أو الأشخاص المتورطين فيه، فيرجى الاتصال [email protected] مع معلومات مفصلة عن المخاوف الخاصة بك.