The bitcoin blockchain is a public ledger that records bitcoin transactions. It is implemented as a chain of blocks, each block containing a hash of the previous block up to the genesis block[a] of the chain. A network of communicating nodes running bitcoin software maintains the blockchain.:215–219 Transactions of the form payer X sends Y bitcoins to payee Z are broadcast to this network using readily available software applications.
Still, even supporters acknowledge that that glorious future is going to use a lot of electricity. It’s true that many of the more alarming claims—for example, that by 2020, bitcoin mining will consume “as much electricity as the entire world does today,” as the environmental website Grist recently suggested—are ridiculous: Even if the current bitcoin load grew a hundredfold, it would still represent less than 2 percent of total global power consumption. (And for comparison, even the high-end estimates of bitcoin’s total current power consumption are still less than 6 percent of the power consumed by the world’s banking sector.) But the fact remains that bitcoin takes an astonishing amount of power. By one estimate, the power now needed to mine a single coin would run the average household for 10 days.
Let’s start with what it’s not doing. Your computer is not blasting through the cavernous depths of the internet in search of digital ore that can be fashioned into bitcoin bullion. There is no ore, and bitcoin mining doesn’t involve extracting or smelting anything. It’s called mining only because the people who do it are the ones who get new bitcoins, and because bitcoin is a finite resource liberated in small amounts over time, like gold, or anything else that is mined. (The size of each batch of coins drops by half roughly every four years, and around 2140, it will be cut to zero, capping the total number of bitcoins in circulation at 21 million.) But the analogy ends there.
Claiming to be the "world's most popular digital wallet," Blockchain.info boasts more than 24 million wallets and has supported more than 100 million transactions. Security is a top priority, and with many longtime cryptocurrency enthusiasts comfortably keeping their spoils there for years, even as Mt. Gox and Bitfinex were breached, it would have to be.
Armory is the most mature, secure and full featured Bitcoin wallet but it can be technologically intimidating for users. Whether you are an individual storing $1,000 or institution storing $1,000,000,000 this is the most secure option available. Users are in complete control all Bitcoin private keys and can setup a secure offline-signing process in Armory.
With no ties to a national economy and lofty goals, Bitcoin's price is famously volatile. Prices have soared and plummeted in the wake of various national policies, financial deals, competing cryptocurrencies, and fluctuating public opinion. On the other hand, as many sovereign nations find themselves with currencies that are also vulnerable, the citizens of countries such as China and Venezuela are turning increasingly to virtual currencies.
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. As a result, the user must have complete trust in the 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. This has led to the often-repeated meme "Not your keys, not your bitcoin".
Bitcoin's most important characteristic is that it is decentralized. No single institution controls the bitcoin network. It is maintained by a group of volunteer coders, and run by an open network of dedicated computers spread around the world. This attracts individuals and groups that are uncomfortable with the control that banks or government institutions have over their money.
If fewer people begin to accept Bitcoin as a currency, these digital units may lose value and could become worthless. There is already plenty of competition, and though Bitcoin has a huge lead over the other 100-odd digital currencies that have sprung up, thanks to its brand recognition and venture capital money, a technological break-through in the form of a better virtual coin is always a threat.
When you pay someone in bitcoin, you set in motion a process of escalating, energy-intensive complexity. Your payment is basically an electronic message, which contains the complete lineage of your bitcoin, along with data about who you’re sending it to (and, if you choose, a small processing fee). That message gets converted by encryption software into a long string of letters and numbers, which is then broadcast to every miner on the bitcoin network (there are tens of thousands of them, all over the world). Each miner then gathers your encrypted payment message, along with any other payment messages on the network at the time (usually in batches of around 2,000), into what’s called a block. The miner then uses special software to authenticate each payment in the block—verifying, for example, that you owned the bitcoin you’re sending, and that you haven’t already sent that same bitcoin to someone else.
OpenDime is the making a name for itself as the “piggy bank” of cold storage units in the world of cryptocurrencies. It functions like other cold storage units with one key exception: one-time secure usage. That one key difference changes quite a lot in the way people use it. Other storage platforms act more like wallets to be used repeatedly with a reasonable degree of security. Whereas an OpenDime unit can be used extremely securely as an address to store Bitcoins until the owner needs to cash out, but only once. In a manner that directly parallels smashing open a piggy bank, once an OpenDime storage unit is “opened” it can no longer be used with the same degree of safety again. OpenDime is a platform that changes the intangible asset of Bitcoin into a physical thing that people can exchange between each other in the real world.
That opportunity may not last. Huffman, who is also a former utility executive, argues that ever-cheaper power rates in other states, like California, could undercut the basin’s appeal to blockchain miners, who may begin to look for other places to mine. For that reason, Huffman argues that the basin should be actively recruiting more miners, even if it means importing power. “I think there’s a window here,” Huffman says, “and it’s unknown how long that window will be open.” Yet he, too, knows that any such talk will lead to criticism that the basin is yoking its future to a volatile sector that, for many, remains a chimera. “Some folks think that bitcoin is just a scam,” Huffman concedes. “And in the conversation, you usually don’t get past that.”
Though transaction fees are optional, miners can choose which transactions to process and prioritize those that pay higher fees. Miners may choose transactions based on the fee paid relative to their storage size, not the absolute amount of money paid as a fee. These fees are generally measured in satoshis per byte (sat/b). The size of transactions is dependent on the number of inputs used to create the transaction, and the number of outputs.:ch. 8