On February 16, 2018, Coinbase admitted that some customers were overcharged in error for credit and debit purchases of cryptocurrencies. The problem was initiated when banks and card issuers changed the merchant category code (MCC) for cryptocurrency purchases earlier this month. This meant that cryptocurrency payments would now be processed as "cash advances", meaning that banks and credit card issuers could begin charging customers cash-advance fees for cryptocurrency purchases. Any customers who purchased cryptocurrency on their exchange between January 22 and February 11, 2018 could have been affected. At first, Visa blamed Coinbase, telling the Financial Times on February 16 that it had "not made any systems changes that would result in the duplicate transactions cardholders are reporting." However, the latest statement from Visa and Worldpay on the Coinbase blog clarifies: "This issue was not caused by Coinbase."[45]

什么是Blockchain PDF


Bitcoin (BTC) is the world’s first decentralized digital currency and payment system and is by far the most known and valuable cryptocurrency. It was created in 2009 by an anonymous person or group called Satoshi Nakamoto. Bitcoin enables transactions to be sent peer-to-peer without passing through a central authority. The transactions are recorded on a decentralized public ledger called the blockchain and each payment acquires a small transaction fee to cover the cost of the network. The total supply of Bitcoin is 21 million and it’s smallest unit of bitcoin is called a Satoshi, it’s a hundred millionth of a bitcoin – 0.00000001 BTC. The creation of Bitcoin’s is happening through mining. Miners have the task to validate transactions and keep the network secure. Their efforts are rewarded by new minted Bitcoins and transactions fees. Bitcoin can be exchanged for fiat or other cryptocurrencies, products and services. Over 100,000 merchants and vendors accepts bitcoin as a payment.

cryptocurrency图表


从广义上来看,网络交换机分为两种:广域网交换机和局域网交换机。广域网交换机主要应用于电信领域,提供通信用的基础平台。而局域网交换机则应用于局域网络,用于连接终端设备,如PC机及网络打印机等。从传输介质和传输速度上可分为以太网交换机、快速以太网交换机、千兆以太网交换机、FDDI交换机、ATM交换机和令牌环交换机等。从规模应用上又可分为企业级交换机、部门级交换机和工作组交换机等。各厂商划分的尺度并不是完全一致的,一般来讲,企业级交换机都是机架式,部门级交换机可以是机架式(插槽数较少),也可以是固定配置式,而工作组级交换机为固定配置式(功能较为简单)。另一方面,从应用的规模来看,作为骨干交换机时,支持500个信息点以上大型企业应用的交换机为企业级交换机,支持300个信息点以下中型企业的交换机为部门级交换机,而支持100个信息点以内的交换机为工作组级交换机。 [3] 

cryptocurrency价格实时走势图


Coinbase has two core products: a Global Digital Asset Exchange (GDAX) for trading a variety of digital assets on its professional asset trading platform, and a user-facing retail broker of Bitcoin, Bitcoin Cash, Ether, Ethereum Classic, and Litecoin for fiat currency.[24] It also offers an API for developers and merchants to build applications and accept payments in both digital currencies. As of 2018, the company offered buy/sell trading functionality in 32 countries,[42] while the cryptocurrency wallet was available in 190 countries worldwide.[43] On March 26, 2018, Coinbase announced their intention to add support for ERC-20 tokens.[44]

是虚拟货币一样Cryptocurrency


With the largest variety of markets and the biggest value - having reached a peak of 18 billion USD - Bitcoin is here to stay. As with any new invention, there can be improvements or flaws in the initial model however the community and a team of dedicated developers are pushing to overcome any obstacle they come across. It is also the most traded cryptocurrency and one of the main entry points for all the other cryptocurrencies. The price is as unstable as always and it can go up or down by 10%-20% in a single day.

可以比特币被复制


In August 2019, Coinbase announced that it was targeted by a sophisticated hacking attack attempt in mid-June. This reported attack used spear-phishing and social engineering tactics (including sending fake e-mails from compromised email accounts and created a landing page at the University of Cambridge) and two Firefox browser zero-day vulnerabilities. One of the Firefox vulnerabilities could allow an attacker to escalate privileges from JavaScript on a browser page (CVE-2019–11707) and the second one could allow the attacker to escape the browser sandbox and execute code on the host computer (CVE-2019–11708). Coinbase's security team detected and blocked the attack, the network was not compromised, and no cryptocurrency was stolen.[39][40][41]

怎么办比特币钱包纸工作

×