Lock and Key

I can hand you the lock, wide open, no disguise Publish it, post it, put it up before your eyes Multiply two huge primes, that's the padlock I made Easy to lock a door that's brutally hard to unbraid

It's a lock and a key, and only one of them's a secret The lock stays public, the key stays yours, that's how you keep it Math built a door that opens one way, shuts one way Anyone can lock a message, only you can make it obey

They call it one-way, easy to walk into, hard to walk back Like shattering glass, or the smoke coming off of a track You can multiply primes in a heartbeat, quick as a spark But unmultiply that product? That takes longer than the dark

It's a lock and a key, and only one of them's a secret Every card you swipe, every message you keep it Riding on a padlock built from numbers this immense That breaking it open would outlast every century since

Somewhere a computer that thinks in a different way Could someday turn that hard math easy, they say Until then the lock holds, the secret stays yours alone A door built from arithmetic, guarding what you've grown

It's a lock and a key, and only one of them's a secret The whole internet runs on trusting math to keep it Nobody guards it with muscle, nobody guards it with a gun Just a number so large that breaking it can't be done