The Ledger Nano is a smartcard based hardware wallet. Private keys are generated and signed offline in the smartcard’s secure environment. The Nano is setup using the Ledger Chrome Application. A random 24-word seed is generated upon setup and backed offline by writing it down on a piece of paper. In case of theft, damage or loss, the entire wallet can be recreated with the seed. A user selected PIN code is also assigned to the device to protect against physical theft or hacking.
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.
The other reason is safety. Looking at 2009 alone, 32,489 blocks were mined; at the then-reward rate of 50 BTC per block, the total payout in 2009 was 1,624,500 BTC, which at today’s prices is over $900 million. One may conclude that only Satoshi and perhaps a few other people were mining through 2009, and that they possess a majority of that $900 million worth of BTC. Someone in possession of that much BTC could become a target of criminals, especially since bitcoins are less like stocks and more like cash, where the private keys needed to authorize spending could be printed out and literally kept under a mattress. While it's likely the inventor of Bitcoin would take precautions to make any extortion-induced transfers traceable, remaining anonymous is a good way for Satoshi to limit exposure.
While senders of traditional electronic payments are usually identified (for verification purposes, and to comply with anti-money laundering and other legislation), users of bitcoin in theory operate in semi-anonymity. Since there is no central "validator," users do not need to identify themselves when sending bitcoin to another user. When a transaction request is submitted, the protocol checks all previous transactions to confirm that the sender has the necessary bitcoin as well as the authority to send them. The system does not need to know his or her identity.
Bitcoin mining is a peer-to-peer process of adding data into Bitcoin’s public ledger in order to verify and secure a contract. Groups of recorded transactions are gathered in blocks and then added into the Bitcoin blockchain. Bitcoin mining requires a lot of resources to protect the network from the possibility of altering past transaction data by making all attempts in changing blocks inefficient for the intruder. Bitcoin mining is rewarded by the network through transaction fees and subsidies of new coins to encourage miners to spend their resources on mining new Bitcoin blocks. As Bitcoin mining is increasingly difficult, it has become impossible to attempt mining as an individual. As a result, most Bitcoin mining is being done by mining pools, which include several participants sharing their reward. Bitcoin mining is controversial, as it is a great tool for securing transactions but complicating the scaling of the network.
Although it is possible to handle bitcoins individually, it would be unwieldy to require a separate transaction for every bitcoin in a transaction. Transactions are therefore allowed to contain multiple inputs and outputs, allowing bitcoins to be split and combined. Common transactions will have either a single input from a larger previous transaction or multiple inputs combining smaller amounts, and one or two outputs: one for the payment, and one returning the change, if any, to the sender. Any difference between the total input and output amounts of a transaction goes to miners as a transaction fee.
A wallet stores the information necessary to transact bitcoins. While wallets are often described as a place to hold or store bitcoins, due to the nature of the system, bitcoins are inseparable from the blockchain transaction ledger. A better way to describe a wallet is something that "stores the digital credentials for your bitcoin holdings" and allows one to access (and spend) them. Bitcoin uses public-key cryptography, in which two cryptographic keys, one public and one private, are generated. At its most basic, a wallet is a collection of these keys.
It would seem even early collaborators on the project don’t have verifiable proof of Satoshi’s identity. To reveal conclusively who Satoshi Nakamoto is, a definitive link would need to be made between his/her activity with Bitcoin and his/her identity. That could come in the form of linking the party behind the domain registration of bitcoin.org, email and forum accounts used by Satoshi Nakamoto, or ownership of some portion of the earliest mined bitcoins. Even though the bitcoins Satoshi likely possesses are traceable on the blockchain, it seems he/she has yet to cash them out in a way that reveals his/her identity. If Satoshi were to move his/her bitcoins to an exchange today, this might attract attention, but it seems unlikely that a well-funded and successful exchange would betray a customer's privacy.
Cryptojacking and legitimate mining, however, are sensitive to cryptocurrency prices, which have declined sharply since their highs in late 2017 and early 2018. According to a McAfee September 2018 threats report, cryptojacking instances “remain very active,” but a decline in the value of cryptocurrencies could lead to a plunge in coin mining malware, just as fast as it emerged.
Electrum gets high marks for its ease of use and user interface, which is always nice, but the real reason it's the best bitcoin wallet for desktop is its safety and reliability. Like any desktop wallet that's worth its salt, users get to control their private key; Electrum doesn't know what it is. Since your private key, a long string of letters and numbers, gives you access to your bitcoin, you need to keep that, you know, private.
The Bitcoin protocol was designed to encourage the distribution of hashing power among miners rather than its concentration. The reason? Miners wield power not only over which transactions get added to the Bitcoin blockchain but over the evolution of the Bitcoin software itself. When updates are made to the protocol, it is the miners, largely, who enforce these changes. If the miners band together and choose not to deploy an update from Bitcoin’s core developers, they can stall transactions or even cause the currency to split into competing versions.
Transactions are defined using a Forth-like scripting language.: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. 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. Any input satoshis not accounted for in the transaction outputs become the transaction fee.