The price of bitcoins has gone through cycles of appreciation and depreciation referred to by some as bubbles and busts.[159] In 2011, the value of one bitcoin rapidly rose from about US$0.30 to US$32 before returning to US$2.[160] In the latter half of 2012 and during the 2012–13 Cypriot financial crisis, the bitcoin price began to rise,[161] reaching a high of US$266 on 10 April 2013, before crashing to around US$50. On 29 November 2013, the cost of one bitcoin rose to a peak of US$1,242.[162] In 2014, the price fell sharply, and as of April remained depressed at little more than half 2013 prices. As of August 2014 it was under US$600.[163] During their time as bitcoin developers, Gavin Andresen[164] and Mike Hearn[165] warned that bubbles may occur.


حاليا لا يُملك مالكو عملات بيتكوين خيارات كثيرة لإنفاق أموالهم من خلالها، وهو ما يدفع ببعضهم إلى استبدالها مقابل العملات التقليدية. يتم ذلك عادة عبر منصات خاصة بذلك حيث يتم استبدال البيتكوينات مع مُستخدمين آخرين لها. يبدو أنه وفي حال ما إذا رغبت الحكومات في معرفة هويات أصحاب بعض الحسابات فما عليها سوى أن تقوم بتقنين عمليات التحويل بدل منعها، حيث سيصبح بالإمكان معرفة اسم صاحب كل حساب بُمجرد أن يرغب في استبدال ما بحوزته مقابل عملات تقليدية، وهو ما يُمثل نقطة انطلاق لتتبع الأموال المسروقة.


The use of bitcoin by criminals has attracted the attention of financial regulators, legislative bodies, law enforcement, and the media.[218] In the United States, the FBI prepared an intelligence assessment,[219] the SEC issued a pointed warning about investment schemes using virtual currencies,[218] and the U.S. Senate held a hearing on virtual currencies in November 2013.[220] The U.S. government claimed that bitcoin was used to facilitate payments related to Russian interference in the 2016 United States elections.[221]
In the end, the majority of the Ethereum community voted to perform a hard fork, and retrieve The DAO investors money. But not everyone agreed with this course of action. This resulted in a split where two parallel blockchains now exist. For those members who strongly disagree with any changes to the blockchain even when hacking occurs there is Ethereum classic. For the majority who agreed to rewrite a small part of the blockchain and return the stolen money to their owners, there is Ethereum.  
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]

Until relatively recently, building blockchain applications has required a complex background in coding, cryptography, mathematics as well as significant resources. But times have changed. Previously unimagined applications, from electronic voting & digitally recorded property assets to regulatory compliance & trading are now actively being developed and deployed faster than ever before. By providing developers with the tools to build decentralized applications, Ethereum is making all of this possible.
The price of bitcoins has gone through cycles of appreciation and depreciation referred to by some as bubbles and busts.[159] In 2011, the value of one bitcoin rapidly rose from about US$0.30 to US$32 before returning to US$2.[160] In the latter half of 2012 and during the 2012–13 Cypriot financial crisis, the bitcoin price began to rise,[161] reaching a high of US$266 on 10 April 2013, before crashing to around US$50. On 29 November 2013, the cost of one bitcoin rose to a peak of US$1,242.[162] In 2014, the price fell sharply, and as of April remained depressed at little more than half 2013 prices. As of August 2014 it was under US$600.[163] During their time as bitcoin developers, Gavin Andresen[164] and Mike Hearn[165] warned that bubbles may occur.
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.
Transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain. Bitcoin was invented by an unknown person or group of people using the name Satoshi Nakamoto[10] and was released as open-source software in 2009.[11] Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services.[12] Research produced by University of Cambridge estimates that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.[13]
البيتكوين عملة رقمية ذات مجهولية، حيث أن عملية التحويل عبرها يتطلب فقط معرفة رقم محفظة الشخص المحول إليه ويتم تخزين عملية التحويل في سلسلة الكتل برقم تسلسلي خاص ولا يتضمن هذا اسم المرسل او المتلقي او اي بيانات اخرى خاصة بهما، مما يجعل منها فكرة رائجة لدى كل من المدافعين عن الخصوصية، أو بائعي البضائع غير المشروعة (مثل المخدرات) عبر الإنترنت على حد سواء.[9]

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.
• 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.
Vitalik Buterin picked the name Ethereum after browsing Wikipedia articles about elements and science fiction, when he found the name, noting, "I immediately realized that I liked it better than all of the other alternatives that I had seen; I suppose it was the fact that sounded nice and it had the word 'ether', referring to the hypothetical invisible medium that permeates the universe and allows light to travel."[9]
Transactions are defined using a Forth-like scripting language.[7]:ch. 5 Transactions consist of one or more inputs and one or more outputs. When a user sends bitcoins, the user designates each address and the amount of bitcoin being sent to that address in an output. To prevent double spending, each input must refer to a previous unspent output in the blockchain.[77] The use of multiple inputs corresponds to the use of multiple coins in a cash transaction. Since transactions can have multiple outputs, users can send bitcoins to multiple recipients in one transaction. As in a cash transaction, the sum of inputs (coins used to pay) can exceed the intended sum of payments. In such a case, an additional output is used, returning the change back to the payer.[77] Any input satoshis not accounted for in the transaction outputs become the transaction fee.[77]
مقارنة بأجزاء أخرى من العالم بدأت الدول العربية في وقت متأخر نسبيا باستخدام بيتكوين حيث أعلن عن قبول هذه العملة لأول مرة في الأردن في بار شاي في العاصمة عمان. وتلى ذلك مطعم بيتزا وصراف آلي في دبي[15] ومن ثم شركة انظمه معلومات في فلسطين[16] كما أصبح سوق السفير من أوئل الاسواق في الكويت و الشرق الأوسط التي تقبل البتكوين في تعاملته [17]. اما بالنسبة للعملة الالكترونية في المشهد الاعلامي العربي فقد بدأت مؤخرا فقرات اخبارية تتحدث عنها ولو بشكل طفيف كما بدأت مواقع متخصصة في اخبار بيتكوين مثل موقع بيتكوين نيوز عربية [18] التابع لمجموعة اعلامية كبيرة،وعلى مستوى الشبكات الاجتماعية يمكن للمستخدمين في الشرق الأوسط وشمال افريقيا التفاعل على موقع askbitcoiner [19] الذي يعتبر أول شبكة اجتماعية للعملة الرقمية في العالم العربي حيث يمكن العثور على الاجوبة للاستفسارات حول العملة الرقمية وتقنية البلوك شاين. وعلى صعيد الشركات اللي توفر خدمات للبيتكون بالوطن العربي فمنهما يلو (بالإنجليزية: Yellow) و بت اويسس (بالإنجليزية: BitOasis) المؤسستان في دبي. بالإضافة إلى بت فلس (بالإنجليزية: BitFils) المؤسسة في الكويت. ويمكن شراء وتداول البيتكوين محليا عن طريق localbitcoins.com .
The use of bitcoin by criminals has attracted the attention of financial regulators, legislative bodies, law enforcement, and the media.[218] In the United States, the FBI prepared an intelligence assessment,[219] the SEC issued a pointed warning about investment schemes using virtual currencies,[218] and the U.S. Senate held a hearing on virtual currencies in November 2013.[220] The U.S. government claimed that bitcoin was used to facilitate payments related to Russian interference in the 2016 United States elections.[221]

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.
In Ethereum all smart contracts are stored publicly on every node of the blockchain, which has costs.[57] Being a blockchain means it is secure by design and is an example of a distributed computing system with high Byzantine fault tolerance. The downside is that performance issues arise in that every node is calculating all the smart contracts in real time, resulting in lower speeds.[57] As of January 2016, the Ethereum protocol could process about 25 transactions per second.[57] In comparison, the Visa payment platform processes 45,000 payments per second leading some to question the scalability of Ethereum.[58] On 19 December 2016, Ethereum exceeded one million transactions in a single day for the first time.[59]
The successful miner finding the new block is allowed by the rest of the network to reward themselves with newly created bitcoins and transaction fees.[88] As of 9 July 2016,[89] the reward amounted to 12.5 newly created bitcoins per block added to the blockchain, plus any transaction fees from payments processed by the block. To claim the reward, a special transaction called a coinbase is included with the processed payments.[7]:ch. 8 All bitcoins in existence have been created in such coinbase transactions. The bitcoin protocol specifies that the reward for adding a block will be halved every 210,000 blocks (approximately every four years). Eventually, the reward will decrease to zero, and the limit of 21 million bitcoins[f] will be reached c. 2140; the record keeping will then be rewarded solely by transaction fees.[90]
In Ethereum all smart contracts are stored publicly on every node of the blockchain, which has costs.[57] Being a blockchain means it is secure by design and is an example of a distributed computing system with high Byzantine fault tolerance. The downside is that performance issues arise in that every node is calculating all the smart contracts in real time, resulting in lower speeds.[57] As of January 2016, the Ethereum protocol could process about 25 transactions per second.[57] In comparison, the Visa payment platform processes 45,000 payments per second leading some to question the scalability of Ethereum.[58] On 19 December 2016, Ethereum exceeded one million transactions in a single day for the first time.[59]
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On 3 January 2009, the bitcoin network was created when Nakamoto mined the first block of the chain, known as the genesis block.[21][22] Embedded in the coinbase of this block was the text "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks".[11] This note references a headline published by The Times and has been interpreted as both a timestamp and a comment on the instability caused by fractional-reserve banking.[23]:18
The proof-of-work system, alongside the chaining of blocks, makes modifications of the blockchain extremely hard, as an attacker must modify all subsequent blocks in order for the modifications of one block to be accepted.[87] As new blocks are mined all the time, the difficulty of modifying a block increases as time passes and the number of subsequent blocks (also called confirmations of the given block) increases.[75]

In the blockchain, bitcoins are registered to bitcoin addresses. Creating a bitcoin address requires nothing more than picking a random valid private key and computing the corresponding bitcoin address. This computation can be done in a split second. But the reverse, computing the private key of a given bitcoin address, is mathematically unfeasible. Users can tell others or make public a bitcoin address without compromising its corresponding private key. Moreover, the number of valid private keys is so vast that it is extremely unlikely someone will compute a key-pair that is already in use and has funds. The vast number of valid private keys makes it unfeasible that brute force could be used to compromise a private key. To be able to spend their bitcoins, the owner must know the corresponding private key and digitally sign the transaction. The network verifies the signature using the public key; the private key is never revealed.[7]:ch. 5
حاليا لا يُملك مالكو عملات بيتكوين خيارات كثيرة لإنفاق أموالهم من خلالها، وهو ما يدفع ببعضهم إلى استبدالها مقابل العملات التقليدية. يتم ذلك عادة عبر منصات خاصة بذلك حيث يتم استبدال البيتكوينات مع مُستخدمين آخرين لها. يبدو أنه وفي حال ما إذا رغبت الحكومات في معرفة هويات أصحاب بعض الحسابات فما عليها سوى أن تقوم بتقنين عمليات التحويل بدل منعها، حيث سيصبح بالإمكان معرفة اسم صاحب كل حساب بُمجرد أن يرغب في استبدال ما بحوزته مقابل عملات تقليدية، وهو ما يُمثل نقطة انطلاق لتتبع الأموال المسروقة.
Here’s why. Ethereum is based on blockchain technology where all transactions are meant to be irreversible and unchangeable. By executing a hard fork and rewriting the rules by which the blockchain executes, Ethereum set a dangerous precedent that goes against the very essence of blockchain. If the blockchain is changed every time a large enough amount of money is involved, or enough people get negatively impacted, the blockchain will lose its main value proposition – secure, anonymous, tamper proof & unchangeable.
This website is intended to provide a clear summary of Ethereum's current and historical price as well as important updates from the industry. I've also included a number of ERC20 tokens which can be found in the tokens tab at the top right. Prices are updated every minute in real-time and the open/close prices are recorded at midnight UTC. Bookmark us!
Bitcoin has been criticized for the amount of electricity consumed by mining. As of 2015, The Economist estimated that even if all miners used modern facilities, the combined electricity consumption would be 166.7 megawatts (1.46 terawatt-hours per year).[136] At the end of 2017, the global bitcoin mining activity was estimated to consume between one and four gigawatts of electricity.[203] Politico noted that the even high-end estimates of bitcoin's total consumption levels amount to only about 6% of the total power consumed by the global banking sector, and even if bitcoin's consumption levels increased 100 fold from today's levels, bitcoin's consumption would still only amount to about 2% of global power consumption.[204]
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