Definition
Plain language
A way of writing numbers using sixteen symbols instead of ten, common throughout computing — which is why a memory address containing the letter 'w' is obviously fake.
As stated in the literature
Base-16 notation using digits 0-9 and letters a-f, standard for representing memory addresses, byte values, and color codes; a character outside that alphabet (e.g. 'w') in a purported address is an immediate tell that the value was fabricated.
Also called: hex
Why it matters: Knowing its limited alphabet lets you instantly catch fabricated addresses or values that could otherwise slip past as plausible.
For example, a real memory address looks like '0x1a3f', so an address containing the letter 'w' is plainly made up.
Heard on the show
“Which isn't a valid hexadecimal character.”Episode 149 — When Cornering a Chatbot Makes It Lie: J.P. Morgan's Case for 'Playing Dead'