“Cryptojacking scams have continued to evolve, and they don’t even need you to install anything,” Jason Adler, an assistant director for the Federal Trade Commission, wrote in a blog post in June. “Scammers can use malicious code embedded in a website or an ad to infect your device. Then they can help themselves to your device’s processor without you even knowing.”
“These companies are using extraordinary amounts of electricity – typically thousands of times more electricity than an average residential customer would use,” a spokesperson for the New York State Department of Public Service told Wired. “The sheer amount of electricity being used is leading to higher costs for customers in small communities because of a limited supply of low-cost hydropower.”
Bitcoin’s first mover advantage, popularity, and network effect has cemented it as the most popular cryptocurrency with the largest market cap. Rivals like Litecoin may have numerous technical advantages over Bitcoin’s algorithm (see more about that here), but they only hold a fraction of Bitcoin’s market cap and their dwindling communities largely consist of loyalists, speculators, and antagonistic anti-Bitcoin buyers.
But, as always, the miners’ biggest challenge came from bitcoin itself. The mere presence of so much new mining in the Mid-Columbia Basin substantially expanded the network’s total mining power; for a time, Carlson’s mine alone accounted for a quarter of the global bitcoin mining capacity. But this rising calculating power also caused mining difficulty to skyrocket—from January 2013 to January 2014, it increased one thousandfold—which forced miners to expand even faster. And bitcoin’s rising price was now drawing in new miners, especially in China, where power is cheap. By the middle of 2014, Carlson says, he’d quadrupled the number of servers in his mine, yet had seen his once-massive share of the market fall below 1 percent.

Bitcoin is in the very early stages of acceptance, and although it is already accepted as a means of payment by numerous merchants, it has yet to become more widely accepted and “mainstream.” This could change, however, as more and more users are attracted to cryptocurrencies for the various potential benefits they may provide. In fact, investors have been flocking to the currency in significant numbers, and some even feel that eventually Bitcoin and other cryptocurrencies could replace other traditional payment methods.
Exchanges, however, are a different story. Perhaps the most notable Bitcoin exchange hack was the Tokyo-based MtGox hack in 2014, where 850,000 bitcoins with a value of over $350 million suddenly disappeared from the platform. This doesn’t mean that Bitcoin itself was hacked; it just means that the exchange platform was hacked. Imagine a bank in Iowa is robbed: the USD didn’t get robbed, the bank did.

Bitcoin Mining is intentionally designed to be resource-intensive and difficult so that the number of blocks found each day by miners remains steady over time, producing a controlled finite monetary supply. Individual blocks must contain a proof-of-work to be considered valid. This proof-of-work (PoW) is verified by other Bitcoin nodes each time they receive a block. Bitcoin uses a PoW function to protect against double-spending, which also makes Bitcoin's ledger immutable.

The code that makes bitcoin mining possible is completely open-source, and developed by volunteers. But the force that really makes the entire machine go is pure capitalistic competition. Every miner right now is racing to solve the same block simultaneously, but only the winner will get the prize. In a sense, everybody else was just burning electricity. Yet their presence in the network is critical.
What separated these survivors from the quitters and the double-downers, Carlson concluded, was simply the price of electricity. Survivors either lived in or had moved to places like China or Iceland or Venezuela, where electricity was cheap enough for bitcoin to be profitable. Carlson knew that if he could find a place where the power wasn’t just cheap, but really cheap, he’d be able to mine bitcoin both profitably and on an industrial scale.
If you've made it this far, then congratulations! There is still so much more to explain about the system, but at least now you have an idea of the broad outline of the genius of the programming and the concept. For the first time we have a system that allows for convenient digital transfers in a decentralized, trust-free and tamper-proof way. The repercussions could be huge.
Miehe still runs his original mine, a half-megawatt operation not far from the carwash. But his main job these days is managing hosting sites for other miners and connecting outsiders with insiders—and he’s OK with that. He sold off some of his bitcoin stack, just after Christmas. He’s still bullish on crypto, and on the basin’s long-term prospects. But he no longer has any appetite for the race for scale. Gone are the glory days when commercial miners could self-finance with their own stacks. Today, you need outside financing—debt—which, for Miehe, who now has two young children, would mean an unacceptable level of stress. “I’ve already done it,” he says. “My entire data center was built with bitcoin, from nothing. I’ve already won enough for what I was looking for out of mining.” He pauses. “The risk and reward is getting pretty great,” he says. “And I’m not sure I want to be on the front line of that battle.”
Researchers have pointed out at a "trend towards centralization". Although bitcoin can be sent directly to the bitcoin network, in practice intermediaries are widely used.[30]:220–222 Bitcoin miners join large mining pools to minimize the variance of their income.[30]:215, 219–222[107]:3[108] Because transactions on the network are confirmed by miners, decentralization of the network requires that no single miner or mining pool obtains 51% of the hashing power, which would allow them to double-spend coins, prevent certain transactions from being verified and prevent other miners from earning income.[109] As of 2013 just six mining pools controlled 75% of overall bitcoin hashing power.[109] In 2014 mining pool Ghash.io obtained 51% hashing power which raised significant controversies about the safety of the network. The pool has voluntarily capped their hashing power at 39.99% and requested other pools to act responsibly for the benefit of the whole network.[110]

A few years ago, CPU and GPU mining became completely obsolete when FPGAs came around. An FPGA is a Field Programmable Gate Array, which can produce computational power similar to most GPUs, while being far more energy‐efficient than graphics cards. Due to its mining efficiency, and ability to consume relatively lesser energy, many miners shifted to the use of FPGAs.
Bitcoin (BTC) is known as the first open-source, peer-to-peer, digital cryptocurrency that was developed and released by a group of unknown independent programmers named Satoshi Nakamoto in 2008. Cryptocoin doesn’t have any centralized server used for its issuing, transactions and storing, as it uses a distributed network public database technology named blockchain, which requires an electronic signature and is supported by a proof-of-work protocol to provide the security and legitimacy of money transactions. The issuing of Bitcoin is done by users with mining capabilities and is limited to 21 million coins. Currently, Bitcoin’s market cap surpasses $138 billion and this is the most popular kind of digital currency. Buying and selling cryptocurrency is available through special Bitcoin exchange platforms or ATMs.
2-3 Wallet: A 2-3 multisig wallet could be used to create secure offline storage with paper wallets or hardware wallets. Users should already backup their offline Bitcoin holdings in multiple locations, and multisig helps add another level of security. A user, for example, may keep a backup of a paper wallet in three separate physical locations. If any single location is compromised the user’s funds can be stolen. Multisignature wallets improve upon this by requiring instead any two of the three backups to spend funds--in the case of a 2-3 multisig wallet. The same setup can be created with any number of signatures. A 5-9 wallet would require any five of the nine signatures in order to spend funds.
In addition to being the means of generating new bitcoin, bitcoin mining creates the blockchain that verifies bitcoin transactions. The block reward is gleaned by placing a new block on the blockchain, which acts as an advancing public ledger of verified transaction. This is an essential function for bitcoin's operation as it enables the currency to be safely and predictably created without the centralized regulation in the form of a bank or federal government. Blocks must to be a validated by a proof-of-work (Bitcoin uses Hashcash), which can only be obtained by expending a great deal of processing power. Once a block is obtained a message is broadcast to the mining network and verified by all recipients. 
In March 2013 the blockchain temporarily split into two independent chains with different rules. The two blockchains operated simultaneously for six hours, each with its own version of the transaction history. Normal operation was restored when the majority of the network downgraded to version 0.7 of the bitcoin software.[36] The Mt. Gox exchange briefly halted bitcoin deposits and the price dropped by 23% to $37[37][38] before recovering to previous level of approximately $48 in the following hours.[39] The US Financial Crimes Enforcement Network (FinCEN) established regulatory guidelines for "decentralized virtual currencies" such as bitcoin, classifying American bitcoin miners who sell their generated bitcoins as Money Service Businesses (MSBs), that are subject to registration or other legal obligations.[40][41][42] In April, exchanges BitInstant and Mt. Gox experienced processing delays due to insufficient capacity[43] resulting in the bitcoin price dropping from $266 to $76 before returning to $160 within six hours.[44] The bitcoin price rose to $259 on 10 April, but then crashed by 83% to $45 over the next three days.[34] On 15 May 2013, US authorities seized accounts associated with Mt. Gox after discovering it had not registered as a money transmitter with FinCEN in the US.[45][46] On 23 June 2013, the US Drug Enforcement Administration (DEA) listed 11.02 bitcoins as a seized asset in a United States Department of Justice seizure notice pursuant to 21 U.S.C. § 881.[47] This marked the first time a government agency had seized bitcoin.[48][49] The FBI seized about 26,000 bitcoins in October 2013 from the dark web website Silk Road during the arrest of Ross William Ulbricht.[50][51][52] Bitcoin's price rose to $755 on 19 November and crashed by 50% to $378 the same day. On 30 November 2013 the price reached $1,163 before starting a long-term crash, declining by 87% to $152 in January 2015.[34] On 5 December 2013, the People's Bank of China prohibited Chinese financial institutions from using bitcoins.[53] After the announcement, the value of bitcoins dropped,[54] and Baidu no longer accepted bitcoins for certain services.[55] Buying real-world goods with any virtual currency had been illegal in China since at least 2009.[56]