Bitcoin Mining

[Kakashi2020]

History of Bitcoin Mining
Between 1 in 16 trillion odds, scaling difficulty levels, and the massive network of users verifying transactions, one block of transactions is verified roughly every 10 minutes.  But it’s important to remember that 10 minutes is a goal, not a rule.

The bitcoin network is currently processing just under four transactions per second as of August 2020, with transactions being logged in the blockchain every 10 minutes.7 For comparison, Visa can process somewhere around 65,000 transactions per second.  As the network of bitcoin users continues to grow, however, the number of transactions made in 10 minutes will eventually exceed the number of transactions that can be processed in 10 minutes. At that point, waiting times for transactions will begin and continue to get longer, unless a change is made to the bitcoin protocol.

This issue at the heart of the bitcoin protocol is known as “scaling.” While bitcoin miners generally agree that something must be done to address scaling, there is less consensus about how to do it. There have been two major solutions proposed to address the scaling problem. Developers have suggested either (1) creating a secondary "off-chain" layer to Bitcoin that would allow for faster transactions that can be verified by the blockchain later, or (2) increasing the number of transactions that each block can store. With less data to verify per block, the Solution 1 would make transactions faster and cheaper for miners. Solution 2 would deal with scaling by allowing for more information to be processed every 10 minutes by increasing block size.

In July 2017, bitcoin miners and mining companies representing roughly 80% to 90% of the network’s computing power voted to incorporate a program that would decrease the amount of data needed to verify each block.

The program that miners voted to add to the bitcoin protocol is called a segregated witness, or SegWit. This term is an amalgamation of Segregated, meaning “to separate,” and Witness, which refers to “signatures on a bitcoin transaction.” Segregated Witness, then, means to separate transaction signatures from a block — and attach them as an extended block. While adding a single program to the bitcoin protocol may not seem like much in the way of a solution, signature data has been estimated to account for up to 65% of the data processed in each block of transactions.

Less than a month later in August 2017, a group of miners and developers initiated a hard fork, leaving the bitcoin network to create a new currency using the same codebase as bitcoin. Although this group agreed with the need for a solution to scaling, they worried that adopting segregated witness technology would not fully address the scaling problem.

Instead, they went with Solution 2. The resulting currency, called “bitcoin cash,” increased the blocksize to 8 MB in order to accelerate the verification process to allow a performance of around 2 million transactions per day. On August 16, 2020, Bitcoin Cash was valued at about $302 to Bitcoin’s roughly $11,800.