Short answers, pulled from the story.
Bitcoin was created in January 2009 by a pseudonymous developer known as Satoshi Nakamoto. It used SHA-256, a cryptographic hash function, in its proof-of-work scheme, and was the first fully realized implementation of the ideas earlier proposed by researchers like David Chaum, Wei Dai, and Nick Szabo.
El Salvador became the first country to accept bitcoin as legal tender on the 9th of June 2021. The Legislative Assembly voted 62-22 to pass a bill submitted by President Nayib Bukele classifying bitcoin as legal tender.
Proof-of-work requires miners to solve complex hashing algorithms using specialized hardware to validate transactions, consuming large amounts of electricity. Proof-of-stake instead requires validators to demonstrate ownership of a certain amount of the currency itself, using a fraction of the energy. Ethereum switched from proof-of-work to proof-of-stake in September 2022 in a process called "the Merge", which its founder said cut energy use and carbon dioxide emissions by 99.9%.
Bitcoin uses 707.6 kilowatt-hours of electricity per transaction, making it the least energy-efficient major cryptocurrency. By comparison, XRP uses just 0.0079 kilowatt-hours per transaction. A 2021 study found that proof-of-stake networks collectively consume 0.001% of the electricity the bitcoin network does.
On the 11th of November 2022, FTX Trading Ltd., which had been valued at $18 billion, filed for bankruptcy. Sam Bankman-Fried was found guilty on seven counts of fraud related to FTX on the 2nd of November 2023, and on the 28th of March 2024 was sentenced to 25 years in prison.
Stablecoins are cryptocurrencies designed to maintain a stable level of purchasing power, typically by pegging their value to a fiat currency. On the 11th of May 2022, Terra's stablecoin UST fell from $1 to 26 cents. The subsequent failure of Terraform Labs resulted in the loss of nearly $40 billion invested in the Terra and Luna coins, and South Korean prosecutors sought an Interpol Red Notice against the company's founder, Do Kwon, in September 2022.