is a peer-to-peer online currency, which means that all transactions take place between equal, independent participants in the network without any intermediary having to authorize or execute them. According to Nakamoto, Bitcoin was created to allow "sending online payments directly from one entity to another entity without going through a financial institution."
Some concepts of a similar kind of decentralized electronic cryptocurrency are older than BTC, but Bitcoin has the distinction of being the very first cryptocurrency that actually started to be used.
Who are the founders of Bitcoin?
The original inventor of Bitcoin is known under the pseudonym Satoshi Nakamoto. As of 2020, the identity of the person or organization behind this alias is still unknown.
In October 2008, Nakomoto published a report detailing how an online peer-to-peer currency could be implemented. It was proposed to use a decentralized master record of transactions, packaged in batches (called "blocks") and secured by cryptographic algorithms. The whole system was later named "blockchain."
Just two months later, on January 3, 2009, Nakamoto mined the first block in the Bitcoin network, known as the birth block, which launched the world's first cryptocurrency.
Although Nakamoto was the original inventor of Bitcoin and the author of its very first implementation, over the years a large number of people have contributed to improving the cryptocurrency's software by fixing vulnerabilities and adding new features.
The Bitcoin source code repository on GitHub lists over 750 contributors. Major contributors include Wladimir J. van der Laan, Marco Falke, Pieter Wuille, Gavin Andresen, Jonas Schnelli and others.
How many Bitcoins are in circulation?
The total amount of Bitcoins is limited by software and will never exceed 21,000,000 coins. New coins are created in a process called "mining": as transactions are transmitted over the network, miners take them and pack them into blocks, which are then protected by complex cryptographic calculations.
As compensation for using their computing resources, miners receive a reward for each block they successfully add to the blockchain. At the time of Bitcoin's launch, the reward was 50 bitcoins per block: this figure is halved after every 210,000 new blocks are mined - which takes the network roughly four years. In 2020, the block reward was halved three times to 6.25 bitcoins.
Bitcoins were not pre-mined, meaning they were not mined and/or distributed to the founders before being made available to the public. But during the early years of BTC's existence, competition between miners was relatively weak, allowing the earliest participants in the network to accumulate a significant amount of coins through regular mining. Satoshi Nakamoto alone is believed to own over a million Bitcoins.
How secure is the Bitcoin network?
Bitcoin is secured using the SHA-256 algorithm, which belongs to the SHA-2 type of hashing algorithms. It is also used by a branch of Bitcoin - Bitcoin Cash (BCH) and several other cryptocurrencies.