Definition
Plain language
A secret code that proves you are you and unlocks access to accounts or data.
As stated in the literature
The secret half of an asymmetric keypair used for signing or decryption; leaking one lets an attacker impersonate the owner or decrypt protected material.
Also called: private keys, private key file
Why it matters: If it leaks, someone else can pretend to be you or read your protected data, so keeping it secret is the whole basis of the trust.
For example, your private key can sign a message so others can be sure it really came from you and not an impostor.
Heard on the show
“From the genuine user sessions specifically, the ones that aren't benchmark runs, that's sixty-two API keys, thirty-three passwords, twenty-four access tokens, and seven private keys.”Episode 238 — How a Cheap Model Reads the Flagship's Secret Reasoning Aloud