A stablecoin is a cryptocurrency designed to hold a steady value against a reference currency — almost always the U.S. dollar. One token is meant to equal one dollar, at all times. The design works only if there is something credible behind that one-dollar promise, and that backing is where stablecoins genuinely differ from one another. The scale is what makes the question matter. As of October 2026, Tether's USDT has roughly $184 billion in circulation, and Circle's USDC has roughly $73 billion — two private dollar tokens moving tens of billions between traders, businesses, and savers every day. They look interchangeable on an exchange screen. They are not. Understanding what sits behind each peg is the whole subject of this post. The One Idea Behind Every Stablecoin Strip away the branding and every stablecoin runs on the same mechanism: confidence in redemption. A token trades at $1 because holders believe they can always get $1 back — by redeeming with the issuer, or by...

A blockchain is a shared record book. Entries are grouped into blocks, and each block carries a cryptographic fingerprint of the block before it, locking the blocks into a chain. On a public blockchain like Bitcoin's, copies of that record book live on many computers at once, and no single company owns it. Change an old entry and you have to rewrite every block after it — and get the rest of the network to accept the rewrite. That is the whole idea, and everything else is detail. Start with the record book, not the coin Strip away the coin and a blockchain is a ledger: a list of who sent what to whom, in what order. Bitcoin's ledger records bitcoin transfers. Other chains record other things. The problem the design solves is agreement: when nobody runs the central office, how do all the record-keepers agree on which entries happened, and in what order? The idea reached the public in October 2008, when a paper titled "Bitcoin: A Peer-to-Peer Electronic Cash System,...