Your Number in the Number Universe

Once we have the fingerprint (hash) of your name, we turn part of it into one big number. That number lives in a special range: 128 bits.

What does “128 bits” mean?

A “bit” is a 0 or a 1. 128 bits means we have 128 such choices in a row. So we’re talking about a number that can be as large as 2^128 minus 1 — roughly 340 undecillion. It’s a number so big that we could give a different one to every grain of sand on Earth and still have plenty left over.

We don’t pick that number randomly. We read the first 16 bytes of your hash (each byte is 8 bits, so 16 × 8 = 128 bits) and interpret them as one number. Then we do two small tweaks so the number is always in a safe, odd range: we set the top bit and the bottom bit. That way we’re always in the “high” part of the 128-bit universe and we’re always odd (which matters for the next step: hunting for a prime).

A spot on the number line

So your name → one recipe → one fingerprint → one starting number on a giant number line. That number is your seed. We don’t give you the seed itself; we start there and walk forward (or sometimes backward) until we find the first prime. That prime is the one we assign to you and register forever.

Think of the 128-bit space as a huge playground. Your seed is your unique starting spot. From there, the hunt for your prime begins.