• لا حرج من دفع عمولات تحويل العملات: كما هو شائع بالنسبة للبعض أن دفع العُمولات عبر شبكات الإنترنت مقابل خدمات تحويل أو شراء عُملات البيتكوين يُعد شكل من أشكال الربا غير المسموح بها. لكن إستناداُ إلى ما تم ذكره بحسب الفتوى رقم 259576 أن لا هناك أى حرج على دفع مثل هذه العمولات. حيث إنك تدفع مُقابل حصولك على خدمة معينة بما فيها خدمات تحويل وشراء عُملات البيتكوين الإفتراضية.
The domain name "bitcoin.org" was registered on 18 August 2008.[17] On 31 October 2008, a link to a paper authored by Satoshi Nakamoto titled Bitcoin: A Peer-to-Peer Electronic Cash System[4] was posted to a cryptography mailing list.[18] Nakamoto implemented the bitcoin software as open-source code and released it in January 2009.[19][20][11] Nakamoto's identity remains unknown.[10]
Various journalists,[205][210] economists,[211][212] and the central bank of Estonia[213] have voiced concerns that bitcoin is a Ponzi scheme. In April 2013, Eric Posner, a law professor at the University of Chicago, stated that "a real Ponzi scheme takes fraud; bitcoin, by contrast, seems more like a collective delusion."[214] A July 2014 report by the World Bank concluded that bitcoin was not a deliberate Ponzi scheme.[215]:7 In June 2014, the Swiss Federal Council[216]:21 examined the concerns that bitcoin might be a pyramid scheme; it concluded that, "Since in the case of bitcoin the typical promises of profits are lacking, it cannot be assumed that bitcoin is a pyramid scheme." In July 2017, billionaire Howard Marks referred to bitcoin as a pyramid scheme.[217]
Izabella Kaminska, the editor of FT Alphaville, has pointed out that criminals are using Ethereum to run Ponzi schemes and other forms of investment fraud.[67] The article was based on a paper from the University of Cagliari, which placed the number of Ethereum smart contracts which facilitate Ponzi schemes at nearly 10% of 1384 smart contracts examined. However, it also estimated that only 0.05% of the transactions on the network were related to such contracts.[68]
Ethereum can also be used to build Decentralized Autonomous Organizations (DAO). A DAO is fully autonomous, decentralized organization with no single leader. DAO’s are run by programming code, on a collection of smart contracts written on the Ethereum blockchain. The code is designed to replace the rules and structure of a traditional organization, eliminating the need for people and centralized control. A DAO is owned by everyone who purchases tokens, but instead of each token equating to equity shares & ownership, tokens act as contributions that give people voting rights.
Bloomberg reported that the largest 17 crypto merchant-processing services handled $69 million in June 2018, down from $411 million in September 2017. Bitcoin is "not actually usable" for retail transactions because of high costs and the inability to process chargebacks, according to Nicholas Weaver, a researcher quoted by Bloomberg. High price volatility and transaction fees make paying for small retail purchases with bitcoin impractical, according to economist Kim Grauer. However, bitcoin continues to be used for large-item purchases on sites such as Overstock.com, and for cross-border payments to freelancers and other vendors.[141]
Using Ethereum’s “Turing complete” smart contract language, Solidity, developers are able to deploy a set of instructions to the blockchain that operate indefinitely with a high degree of finality and fraud-resistance. With the first block being mined in July 2015, Ethereum has since become the largest smart contract platform of its kind, and the second largest blockchain of all time as measured by market capitalization.
Ethereum was initially described in a white paper by Vitalik Buterin,[10] a programmer involved with Bitcoin Magazine, in late 2013 with a goal of building decentralized applications.[11][12] Buterin had argued that Bitcoin needed a scripting language for application development. Failing to gain agreement, he proposed development of a new platform with a more general scripting language.[4]:88
The unit of account of the bitcoin system is a bitcoin. Ticker symbols used to represent bitcoin are BTC[a] and XBT.[b][72]:2 Its Unicode character is ₿.[1] Small amounts of bitcoin used as alternative units are millibitcoin (mBTC), and satoshi (sat). Named in homage to bitcoin's creator, a satoshi is the smallest amount within bitcoin representing 0.00000001 bitcoins, one hundred millionth of a bitcoin.[2] A millibitcoin equals 0.001 bitcoins; one thousandth of a bitcoin or 100,000 satoshis.[73]
Third-party internet services called online wallets offer similar functionality but may be easier to use. In this case, credentials to access funds are stored with the online wallet provider rather than on the user's hardware.[97] As a result, the user must have complete trust in the online wallet provider. A malicious provider or a breach in server security may cause entrusted bitcoins to be stolen. An example of such a security breach occurred with Mt. Gox in 2011.[98]
Ethereum’s core innovation, the Ethereum Virtual Machine (EVM) is a Turing complete software that runs on the Ethereum network. It enables anyone to run any program, regardless of the programming language given enough time and memory. The Ethereum Virtual Machine makes the process of creating blockchain applications much easier and efficient than ever before. Instead of having to build an entirely original blockchain for each new application, Ethereum enables the development of potentially thousands of different applications all on one platform.
Bitcoin is a digital asset designed to work in peer-to-peer transactions as a currency.[4][135] Bitcoins have three qualities useful in a currency, according to The Economist in January 2015: they are "hard to earn, limited in supply and easy to verify."[136] Per some researchers, as of 2015, bitcoin functions more as a payment system than as a currency.[32]

Computing power is often bundled together or "pooled" to reduce variance in miner income. Individual mining rigs often have to wait for long periods to confirm a block of transactions and receive payment. In a pool, all participating miners get paid every time a participating server solves a block. This payment depends on the amount of work an individual miner contributed to help find that block.[92]
من منظور المنقبين فإن سعر البيتكوين الحالي أقل بكثير مما يجب عليه أن يكون، ولهذا ستجد أنه لا رغبة لديهم في بيع العُملات التي بحوزتهم بأسعار مُنخفضة لأنهم قد استخدموا كميات هائلة من الكهرباء لإنتاجها، إضافة إلى الاستثمار في عتاد خاص للقيام بذلك. الوضع سيزداد سوءا بالنسبة إليهم ما لم ينخفض عدد المُنقبين بشكل مُعتبر، حيث أن عدد العُملات التي سيتم إنتاجها ستنخفض إلى النصف كل 4 سنوات. في المقابل، تم إنتاج كميات كبيرة من البيتكوينات بشكل رخيص جدا في بدايات العُملة لما كان عدد المُنقبين قليلا ولما كان عامل “الصعوبة” hardness منخفضا جدا، وبالتالي حاجة إلى كهرباء أقل، هذا الأمر خلق حالة من اللاتوازن داخل شبكة العُملة، حيث بإمكان أصحاب البيتكوينات القديمة بيع عُملاتهم دون تسجيل خسائر مُقارنة بمن انضموا إلى جبهة المُنقبين مؤخرا.
^ "Crib Sheet: Neptune's Brood – Charlie's Diary". www.antipope.org. Archived from the original on 14 June 2017. Retrieved 5 December 2017. I wrote Neptune's Brood in 2011. Bitcoin was obscure back then, and I figured had just enough name recognition to be a useful term for an interstellar currency: it'd clue people in that it was a networked digital currency.

^ Beikverdi, A.; Song, J. (June 2015). Trend of centralization in Bitcoin's distributed network. 2015 IEEE/ACIS 16th International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing (SNPD). pp. 1–6. doi:10.1109/SNPD.2015.7176229. ISBN 978-1-4799-8676-7. Archived from the original on 26 January 2018.
In March 2017, various blockchain start-ups, research groups, and Fortune 500 companies announced the creation of the Enterprise Ethereum Alliance (EEA) with 30 founding members.[16] By May, the nonprofit organization had 116 enterprise members—including ConsenSys, CME Group, Cornell University's research group, Toyota Research Institute, Samsung SDS, Microsoft, Intel, J. P. Morgan, Cooley LLP, Merck KGaA, DTCC, Deloitte, Accenture, Banco Santander, BNY Mellon, ING, and National Bank of Canada.[17][18][19] By July 2017, there were over 150 members in the alliance, including recent additions MasterCard, Cisco Systems, Sberbank and Scotiabank.[20][21]
Venture capitalists, such as Peter Thiel's Founders Fund, which invested US$3 million in BitPay, do not purchase bitcoins themselves, but instead fund bitcoin infrastructure that provides payment systems to merchants, exchanges, wallet services, etc.[154] In 2012, an incubator for bitcoin-focused start-ups was founded by Adam Draper, with financing help from his father, venture capitalist Tim Draper, one of the largest bitcoin holders after winning an auction of 30,000 bitcoins,[155] at the time called "mystery buyer".[156] The company's goal is to fund 100 bitcoin businesses within 2–3 years with $10,000 to $20,000 for a 6% stake.[155] Investors also invest in bitcoin mining.[157] According to a 2015 study by Paolo Tasca, bitcoin startups raised almost $1 billion in three years (Q1 2012 – Q1 2015).[158] 

بيتكوين (بالإنجليزية: Bitcoin) هي عملة معماة ونظام دفع عالمي يمكن مقارنتها بالعملات الأخرى مثل الدولار أو اليورو، لكن مع عدة فوارق أساسية، من أبرزها أن هذه العملة هي عملة إلكترونية بشكل كامل تتداول عبر الإنترنت فقط من دون وجود فيزيائي لها.[1] وهي أول عملة رقمية لامركزية - فهي نظام يعمل دون مستودع مركزي أو مدير واحد، أي أنها تختلف عن العملات التقليدية بعدم وجود هيئة تنظيمية مركزية تقف خلفها. وتتم المعاملات بشبكة الند للند بين المستخدمين مباشرة دون وسيط من خلال استخدام التشفير. يتم التحقق من هذه المعاملات عن طريق عُقد الشبكة وتسجيلها في دفتر حسابات موزع وعام يسمى سلسلة الكتل. اخترع البيتكوين شخص غير معروف أو مجموعة من الناس عرف باسم ساتوشي ناكاموتو وأُصدِر كبرنامج مفتوح المصدر في عام 2009.
Ethereum blockchain applications are usually referred to as DApps (decentralized application), since they are based on the decentralized Ethereum Virtual Machine, and its smart contracts.[46] Many uses have been proposed for Ethereum platform, including ones that are impossible or unfeasible.[47][33] Use case proposals have included finance, the internet-of-things, farm-to-table produce, electricity sourcing and pricing, and sports betting. Ethereum is (as of 2017) the leading blockchain platform for initial coin offering projects, with over 50% market share.

Ethereum's blockchain uses Merkle trees, for security reasons, to improve scalability, and to optimize transaction hashing.[61] As with any Merkle tree implementation, it allows for storage savings, set membership proofs (called "Merkle proofs"), and light client synchronization. The Ethereum network has at times faced congestion problems, for example, congestion occurred during late 2017 in relation to Cryptokitties.[62]
Blockchain analysts estimate that Nakamoto had mined about one million bitcoins[28] before disappearing in 2010, when he handed the network alert key and control of the code repository over to Gavin Andresen. Andresen later became lead developer at the Bitcoin Foundation.[29][30] Andresen then sought to decentralize control. This left opportunity for controversy to develop over the future development path of bitcoin, in contrast to the perceived authority of Nakamoto's contributions.[31][30]
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