Blockchain is a kind of record-keeping technology which stores data in blocks that it chains together chronologically each time new data is added, creating an ever-expanding link of information that is continuously verified by a vast network of server farms and individual "miners." This peer-to-peer verification keeps the information very secure, but also results in an extremely high electricity consumption to maintain the networks (currently estimated at over 130 Terrawatt hours in a year, or 0.6% of global electricity consumption).

A basic purpose of Blockchain is to be able to assign a unique identity to a tradeable piece of digital information, preventing attempts to alter or replicate it (because the peer-to-peer verification system mentioned above would detect such violations).

A core use of Blockchain is cryptocurrencies like Bitcoin and Etherium, which are able to function as a decentralized currency without a central bank or government’s control. The blockchain is used to store a ledger of transactions on each coin, and the verification system keeps in place an artificial scarcity that prevents more from being "printed out." Some other examples include the NFT (Non-Fungible Token) - a way of trading "ownership" of digital art by storing unique links to art pieces in blockchain form - as well as digital collectibles.

An out-of-court settlement is when an arrangement is made formally between all parties involved in a lawsuit to resolve the dispute without the court's involvement - usually through financial compensation or mediation.

"Vaccine passports" are documents that are currently being considered or adopted by many countries in the attempt to reopen some economic activities during Covid-19. These can be apps or documentation to prove that an individual has received the full dose of vaccination or has already survived the disease and has immunity that way.

They can be required for domestic economic activities, such as attending bars or concerts, or considered for the purposes of international travel, such as allowing those with a vaccine passport to bypass quarantine.