Definition
Plain language
The system of digital keys and certificates that lets strangers on the internet exchange encrypted messages without ever having met.
As stated in the literature
PKI — a framework of public/private key pairs and certificate authorities enabling authenticated, encrypted communication between parties with no prior shared secret; contrasted in steganographic-coordination work with symmetric shared-key setups.
Also called: PKI
Why it matters: It makes secure communication possible between strangers online without any prior shared secret, underpinning everyday web encryption.
For example, when you visit a secure website, this system lets your browser encrypt a connection to a server you've never contacted before.
Heard on the show
“… knobs: whether the scheme had to be undetectable, whether they shared a secret key or used public-key infrastructure, and whether the common knowledge was spelled out. …”Episode 184 — An AI Built an Undetectable Secret Channel, And Another AI Couldn't Find It