Skip to main content
Back to the atlas
Q-Day Simulator

Are you already exposed?

Describe your situation — the data you hold, how long it must stay secret, how long your migration takes, when a quantum computer might arrive, and the crypto you use today. The verdict updates live.

What kind of data?

Decades of confidentiality; a diagnosis doesn't expire.

25 years

How long this data must remain secret.

7 years

How long it takes you to roll out PQC.

10 years

When a cryptographically-relevant quantum computer (CRQC) arrives.

What protects it today?
Critical

Already exposed

This data must stay secret for 25 years, but a quantum computer may exist in 10. Anything an adversary records today can be decrypted well inside that window — classic harvest-now-decrypt-later. By Mosca's inequality (X + Y = 32 > Z = 10) you have already failed for this data class.

Mosca’s inequalityX + Y = 32 > Z = 10
X data lifetime · 25yY migration · 7y

Harvest-now-decrypt-later is active. The deadline for confidentiality is today, not Q-Day — ciphertext captured now sits in storage until a quantum computer can open it.

Signatures are different. A signature only needs to be quantum-safe by the time a CRQC exists — there’s no retroactive risk. Encrypted secrets get no such grace period, which is why confidentiality migrates first.

About this lab — Q-Day Simulator

What this lab teaches

Your own Q-Day verdict — combine the kind of data you hold, how long it must stay confidential, how long your migration takes, when a quantum computer might arrive, and the cryptography you use today.

How to use it

  1. Pick a data type and the algorithm you currently rely on.
  2. Set the confidentiality-lifetime, migration-time, and quantum-arrival sliders.
  3. Read the verdict, then the reasoning that produced it.

Key takeaway

Harvest-now-decrypt-later means the deadline for confidentiality is today, not Q-Day. Signatures only need to be quantum-safe by the time a CRQC exists; harvested ciphertext does not get that grace period.

Related exhibits