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]
Mining is a record-keeping service done through the use of computer processing power.[e] Miners keep the blockchain consistent, complete, and unalterable by repeatedly grouping newly broadcast transactions into a block, which is then broadcast to the network and verified by recipient nodes.[75] Each block contains a SHA-256 cryptographic hash of the previous block,[75] thus linking it to the previous block and giving the blockchain its name.[7]:ch. 7[75]
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.  
To be accepted by the rest of the network, a new block must contain a proof-of-work (PoW).[75] The system used is based on Adam Back's 1997 anti-spam scheme, Hashcash.[85][4] The PoW requires miners to find a number called a nonce, such that when the block content is hashed along with the nonce, the result is numerically smaller than the network's difficulty target.[7]:ch. 8 This proof is easy for any node in the network to verify, but extremely time-consuming to generate, as for a secure cryptographic hash, miners must try many different nonce values (usually the sequence of tested values is the ascending natural numbers: 0, 1, 2, 3, ...[7]:ch. 8) before meeting the difficulty target.
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.
• 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.
Smart contract is just a phrase used to describe a computer code that can facilitate the exchange of money, content, property, shares, or anything of value. When running on the blockchain a smart contract becomes like a self-operating computer program that automatically executes when specific conditions are met. Because smart contracts run on the blockchain, they run exactly as programmed without any possibility of censorship, downtime, fraud or third-party interference.
Every 2,016 blocks (approximately 14 days at roughly 10 min per block), the difficulty target is adjusted based on the network's recent performance, with the aim of keeping the average time between new blocks at ten minutes. In this way the system automatically adapts to the total amount of mining power on the network.[7]:ch. 8 Between 1 March 2014 and 1 March 2015, the average number of nonces miners had to try before creating a new block increased from 16.4 quintillion to 200.5 quintillion.[86]

Physical wallets store the credentials necessary to spend bitcoins offline and can be as simple as a paper printout of the private key;[7]:ch. 10 a paper wallet. A paper wallet is created with a keypair generated on a computer with no internet connection; the private key is written or printed onto the paper[g] and then erased from the computer. The paper wallet can then be stored in a safe physical location for later retrieval. Bitcoins stored using a paper wallet are said to be in cold storage.[99]:39 In a 2014 interview, QuadrigaCX founder Gerald Cotten explained that the company stored customer funds on paper wallets in safe deposit boxes: "So we just send money to them, we don’t need to go back to the bank every time we want to put money into it. We just send money from our Bitcoin app directly to those paper wallets, and keep it safe that way."[100]
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!
تُعتبر بيتكوين عُملة معمّاة (بالإنجليزية: cryptocurrency) ويُقصد بذلك أنها تعتمد بشكل أساسي على مبادئ التشفير في جميع جوانبها، كما أنها تُعتبر أيضا العُملة الأولى من نوعها والأكثر شهرة وانتشارًا لكن رغم ذلك ليست العُملة التشفيرية الوحيدة الموجودة على شبكة الإنترنت حاليًا. حيث يتوفر ما يزيد عن 60 عُملة تشفيرية مُختلفة[6] منها 6 عُملات يُمكن وصفها بالرئيسية [7] وذلك اعتمادًا على عدد المُستخدمين وبنية كل شبكة، إضافة إلى الأماكن التي يُمكن استبدال وشراء هذه العُملات التشفيرية مُقابل عُملات أخرى. جميع العُملات التشفيرية الحالية مبنية على مبدأ عمل عُملة بيتكوين نفسها باستثناء عُملة Ripple [8]، وبما أن عُملة بيتكوين مفتوحة المصدر فإنه من المُمكن استنساخها وإدخال بعض التعديلات عليها ومن ثم إطلاق عُملة جديدة.
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
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]
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 .

Ethereum was officially with an unusually long list of founders. Anthony Di Iorio wrote "Ethereum was founded by Vitalik Buterin, Myself, Charles Hoskinson, Mihai Alisie, & Amir Chetrit (the initial 5) in December 2013. Joseph Lubin, Gavin Wood, & Jeffrey Wilke were added in early 2014 as founders." Formal development of the Ethereum software project began in early 2014 through a Swiss company, Ethereum Switzerland GmbH (EthSuisse).[13][14] The basic idea of putting executable smart contracts in the blockchain needed to be specified before the software could be implemented; this work was done by Gavin Wood, then chief technology officer, in the Ethereum Yellow Paper that specified the Ethereum Virtual Machine.[15] Subsequently, a Swiss non-profit foundation, the Ethereum Foundation (Stiftung Ethereum), was created as well. Development was funded by an online public crowdsale during July–August 2014, with the participants buying the Ethereum value token (ether) with another digital currency, bitcoin.


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According to The New York Times, libertarians and anarchists were attracted to the idea. Early bitcoin supporter Roger Ver said: "At first, almost everyone who got involved did so for philosophical reasons. We saw bitcoin as a great idea, as a way to separate money from the state."[126] The Economist describes bitcoin as "a techno-anarchist project to create an online version of cash, a way for people to transact without the possibility of interference from malicious governments or banks".[129]
Ethereum has recently created a new standard called the ERC721 token for tracking unique digital assets. One of the biggest use cases currently for such tokens is digital collectibles, as the infrastructure allows for people to prove ownership of scarce digital goods. Many games are currently being built using this technology, such as the overnight hit CryptoKitties, a game where you can collect and breed digital cats.
Ether is a token whose blockchain is generated by the Ethereum platform. Ether can be transferred between accounts and used to compensate participant mining nodes for computations performed.[3] Ethereum provides a decentralized virtual machine, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes.[4] The virtual machine's instruction set, in contrast to others like Bitcoin Script, is thought to be Turing-complete. "Gas", an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network.[4]
^ 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.
الجدير بالذكر بأن بعض المواقع كانت تنشر سابقا تقديرا لمقدار الخسارة/ الربح الذي يُسجله المنقبون لكن يبدو بأنهم توقفوا عن القيام بذلك لأسباب نجهلها. قد يعتقد البعض بأنه لم يكن بالإمكان إعطاء تقدير دقيق لمقدار الخسارة أو الربح الذي يُسجله المنقبون، ولذلك تم التخلص من ذلك. إلا أنه من المُمكن جدا أنه تم التخلص من ذلك لكيلا يتم تنفير المُنقبين من عمليات التنقيب.
Ethereum was announced at the North American Bitcoin Conference in Miami, in January, 2014.[9] During the same time as the conference, a group of people rented a house in Miami Gavin Wood, Charles Hoskinson, and Anthony Di Iorio, a Torontonian who financed the project.[9] Di Iorio invited friend Joseph Lubin, who invited reporter Morgen Peck, to bear witness.[9] Six months later the founders met again in a house in Zug Switzerland, where Buterin told the founders that the project would proceed as a non-profit. Hoskinson left the project at that time.[9]
Smart contract is just a phrase used to describe a computer code that can facilitate the exchange of money, content, property, shares, or anything of value. When running on the blockchain a smart contract becomes like a self-operating computer program that automatically executes when specific conditions are met. Because smart contracts run on the blockchain, they run exactly as programmed without any possibility of censorship, downtime, fraud or third-party interference.

The first wallet program, simply named Bitcoin, and sometimes referred to as the Satoshi client, was released in 2009 by Satoshi Nakamoto as open-source software.[11] In version 0.5 the client moved from the wxWidgets user interface toolkit to Qt, and the whole bundle was referred to as Bitcoin-Qt.[107] After the release of version 0.9, the software bundle was renamed Bitcoin Core to distinguish itself from the underlying network.[108][109]
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]
Ethereum is the pioneer for blockchain based smart contracts. When running on the blockchain a smart contract becomes like a self-operating computer program that automatically executes when specific conditions are met. On the blockchain, smart contracts allow for code to be run exactly as programmed without any possibility of downtime, censorship, fraud or third-party interference. It can facilitate the exchange of money, content, property, shares, or anything of value. The Ethereum network went live on July 30th, 2015 with 72 million Ethereum premined.
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.
The Bank for International Settlements summarized several criticisms of bitcoin in Chapter V of their 2018 annual report. The criticisms include the lack of stability in bitcoin's price, the high energy consumption, high and variable transactions costs, the poor security and fraud at cryptocurrency exchanges, vulnerability to debasement (from forking), and the influence of miners.[189][190][191]
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]
• 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.
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 .

• غطاء تمويلى للمنظمات الإرهابية: قامت دار الإفتاء المصرية بتصريح أن عمليات الإستثمار والتداول في البيتكوين تُعتبر عمليات مُحرمة من قبل الدين والشرع حيث إنها تعمل كغطاء لتمويل المنظمات الإرهابية وعصابات المُخدرات. كما لعدم وجود هيئات حكومية وبنوك مركزية كان لذلك آثر رهيب على استخدام إستثمارات البيتكوين في عمليات غسيل الأموال والتى بالطبع نهانا الرسول عنها، بل ويُحاسب عليها القانون أيضاً.


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]
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