5 April 2020
Bonus blog: Technology to watch – Bitcoin, cryptocurrency, blockchain technology
According to CoinMetrics and Forbes, on 11 March 281,000 bitcoins were sold by owners who held them for only thirty days. This compared to 4,131 bitcoins that had laid dormant for a year or more indicating that the vast majority of the bitcoin volatility on that day was from recent buyers. During the week of 11 March 2020 as a result of the 2019–20 coronavirus pandemic cryptocurrency exchange Kraken experienced an 83% increase in the amount of account signups over the week of bitcoin’s price collapse, a result of buyers looking to capitalize on the low price.
A cryptocurrency (or crypto currency) is a digital asset designed to work as a medium of exchange that uses strong cryptography to secure financial transactions, control the creation of additional units, and verify the transfer of assets.
A Peer-to-Peer Electronic Cash System was posted to a cryptography mailing list. Nakamoto implemented the bitcoin software as open-source code and released it in January 2009. Nakamoto’s identity remains unknown.
Bitcoin (₿) is a cryptocurrency. It is a decentralized digital currency without a central bank or single administrator that can be sent from user to user on the peer-to-peer bitcoin network without the need for intermediaries.
Transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain. Bitcoin was invented in 2008 by an unknown person or group of people using the name Satoshi Nakamoto and started in 2009 when its source code was released as open-source software. Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. Research produced by University of Cambridge estimates that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.
On 3 January 2009, the bitcoin network was created when Nakamoto mined the first block of the chain, known as the genesis block. Embedded in the coinbase of this block was the text “The Times 03/Jan/2009 Chancellor on brink of second bailout for banks”. This note references a headline published by The Times and has been interpreted as both a timestamp and a comment on the instability caused by fractional-reserve banking.
The blocks in the blockchain were originally limited to 32 megabytes in size. The block size limit of one megabyte was introduced by Satoshi Nakamoto in 2010. Eventually the block size limit of one megabyte created problems for transaction processing, such as increasing transaction fees and delayed processing of transactions. Andreas Antonopoulos has stated Lightning Network is a potential scaling solution and referred to lightning as a second layer routing network.
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 of the chain. A network of communicating nodes running bitcoin software maintains the blockchain. Transactions of the form payer X sends Y bitcoins to payee Z are broadcast to this network using readily available software applications.
Network nodes can validate transactions, add them to their copy of the ledger, and then broadcast these ledger additions to other nodes. To achieve independent verification of the chain of ownership each network node stores its own copy of the blockchain. About every 10 minutes, a new group of accepted transactions, called a block, is created, added to the blockchain, and quickly published to all nodes, without requiring central oversight. This allows bitcoin software to determine when a particular bitcoin was spent, which is needed to prevent double-spending. A conventional ledger records the transfers of actual bills or promissory notes that exist apart from it, but the blockchain is the only place that bitcoins can be said to exist in the form of unspent outputs of transactions.
Data structure of blocks in the ledger.
In the blockchain, bitcoins are registered to bitcoin addresses. Creating a bitcoin address requires nothing more than picking a random valid private key and computing the corresponding bitcoin address.
To ensure the security of bitcoins, the private key must be kept secret. If the private key is revealed to a third party, e.g. through a data breach, the third party can use it to steal any associated bitcoins. As of December 2017, around 980,000 bitcoins have been stolen from cryptocurrency exchanges.
Regarding ownership distribution, as of 16 March 2018, 0.5% of bitcoin wallets own 87% of all bitcoins ever mined.
Mining is a record-keeping service done through the use of computer processing power. 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. Each block contains a SHA-256 cryptographic hash of the previous block, thus linking it to the previous block and giving the blockchain its name. To be accepted by the rest of the network, a new block must contain a proof-of-work (PoW).
The successful miner finding the new block is allowed by the rest of the network to reward themselves with newly created bitcoins and transaction fees. As of 9 July 2016, the reward amounted to 12.5 newly created bitcoins per block added to the blockchain, plus any transaction fees from payments processed by the block.
The bitcoin protocol specifies that the reward for adding a block will be halved every 210,000 blocks (approximately every four years). Eventually, the reward will decrease to zero, and the limit of 21 million bitcoins will be reached c. 2140; the record keeping will then be rewarded solely by transaction fees.
In other words, Nakamoto set a monetary policy based on artificial scarcity at bitcoin’s inception that the total number of bitcoins could never exceed 21 million. New bitcoins are created roughly every ten minutes and the rate at which they are generated drops by half about every four years until all will be in circulation.
Computing power is often bundled together or “pooled” to reduce variance in miner income. Individual mining rigs often have to wait for long periods to confirm a block of transactions and receive payment. In a pool, all participating miners get paid every time a participating server solves a block. This payment depends on the amount of work an individual miner contributed to help find that block.
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 wallet is more correctly defined as 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. There are several modes which wallets can operate in. They have an inverse relationship with regards to trustlessness and computational requirements.
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 online 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.
A paper wallet with the address visible for adding or checking stored funds. The part of the page containing the private key is folded over and sealed.
A brass token with a private key hidden beneath a tamper-evident security hologram. A part of the address is visible through a transparent part of the hologram.
A hardware wallet peripheral which processes bitcoin payments without exposing any credentials to the computer.
Physical wallets store the credentials necessary to spend bitcoins offline and can be as simple as a paper printout of the private key: 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 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.
Bitcoin is decentralized:
• Bitcoin does not have a central authority.
• There is no central server; the bitcoin network is peer-to-peer.
• There is no central storage; the bitcoin ledger is distributed.
• The ledger is public; anybody can store it on their computer.
• There is no single administrator; the ledger is maintained by a network of equally privileged miners.
• Anybody can become a miner.
• The additions to the ledger are maintained through competition. Until a new block is added to the ledger, it is not known which miner will create the block.
• The issuance of bitcoins is decentralized. They are issued as a reward for the creation of a new block.
• Anybody can create a new bitcoin address (a bitcoin counterpart of a bank account) without needing any approval.
• Anybody can send a transaction to the network without needing any approval; the network merely confirms that the transaction is legitimate.
Trend towards centralization
Researchers have pointed out at a “trend towards centralization”. Although bitcoin can be sent directly from user to user, in practice intermediaries are widely used. Bitcoin miners join large mining pools to minimize the variance of their income. 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. As of 2013 just six mining pools controlled 75% of overall bitcoin hashing power. 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. c. 2017 over 70% of the hashing power and 90% of transactions were operating from China.
Bitcoin is pseudonymous, meaning that funds are not tied to real-world entities but rather bitcoin addresses. Owners of bitcoin addresses are not explicitly identified, but all transactions on the blockchain are public. In addition, transactions can be linked to individuals and companies through “idioms of use” (e.g., transactions that spend coins from multiple inputs indicate that the inputs may have a common owner) and corroborating public transaction data with known information on owners of certain addresses. Additionally, bitcoin exchanges, where bitcoins are traded for traditional currencies, may be required by law to collect personal information. To heighten financial privacy, a new bitcoin address can be generated for each transaction.
Wallets and similar software technically handle all bitcoins as equivalent, establishing the basic level of fungibility. Researchers have pointed out that the history of each bitcoin is registered and publicly available in the blockchain ledger, and that some users may refuse to accept bitcoins coming from controversial transactions, which would harm bitcoin’s fungibility. For example, in 2012, Mt. Gox froze accounts of users who deposited bitcoins that were known to have just been stolen.
In conclusion, we found it necessary to add this blog during these times of considerable economic uncertainty. With the world economy in turmoil, more and more people will be turning to cryptocurrencies in a way to fully control their assets. This blog attempts to give our readers a basic understanding of how bitcoin the most popular decentralized cryptocurrency works.
Nexonta Technologies Inc.