Blockchains

Ownership on the Bitcoin blockchain is determined by a pair of cryptographic keys. The first, called the public key, resides in the blockchain for anyone to see. The second is called the private key, and its owner keeps it safe from view. The two keys have a special mathematical relationship that makes them useful for signing digital messages. Here’s how that happens: Helmut takes a message, combines it with his private key, does some calculations, and ends up with a long number. Anyone who...

 The Molecular Beauty of a Butterfly

When I see the butterfly, I imagine in my mind's eye the extraordinary chemical machinery of life, the winding loom of he DNA, the proteins linking like lock and key, the ceaseless hubbub of molecular commerce that goes on behind the scenes, from egg, to caterpillar, to chrysalis, to adult. Surely, no land of faerie is more magical than the transformation that occurs in the chrysalis, when a creepy-crawly caterpillar curls up in a self-made sack and rearranges its molecules to emerge as a win...