Bitcoin was the first cryptocurrency to appear, and it remains the most popular. Satoshi Nakamoto, a pseudonymous developer, established it in 2009. The fundamental idea was to create an autonomous and decentralised electronic payment system based on mathematical proofs and encryption. While Bitcoin is the most well-known, it is far from the only cryptocurrency. There are several varieties of cryptocurrencies, each with its own set of characteristics and activities. However, not all of them have their own blockchain, thus some have been built on top of an existing one.
Bitcoin is a network of computers called nodes that collaborate to execute the Bitcoin code and store the blockchain. A blockchain may be thought of as a series of blocks. Each block contains a transaction sequence. Nobody can monitor the process because all computers running the blockchain use the same block and transaction list and can view these fresh blocks loaded with new Bitcoin transactions in real time. Anyone, whether or not they operate a Bitcoin "node," may view these transactions in real time. To commit a crime, a bad actor will need to control 51% of the processing power that makes up Bitcoin. Bitcoin has about 47,000 nodes as of May 2020.

Bitcoin longs and shorts represent opposing market positions taken by traders. A long position involves buying Bitcoin with the expectation that its price will rise, allowing the trader to sell later for a profit. In contrast, a short position involves borrowing Bitcoin (or using derivatives) to sell it at the current price, anticipating a decline in value, so it can be repurchased at a lower price for profit.

The balance between longs and shorts reflects market sentiment. A market dominated by longs signals bullish sentiment, while more shorts indicate bearish expectations. Tools like the long/short ratio provide insights into trader positioning. Effective trading requires understanding market dynamics, leverage risks, and how sentiment can influence Bitcoin's volatile price movements.