← Entropy Atlas
Secret & unpredictable
Symmetric encryption keys
One shared secret locks and unlocks data with algorithms such as AES.
Evaluation card
What “plenty” means here.
- Required property
- A key sampled across the algorithm’s supported key space, without a smaller predictable seed hiding underneath.
- If it fails
- A guessable key turns strong encryption into a short search through likely keys.
- Relevant attacker
- An offline attacker with ciphertext, known structure, and hardware specialized for the exact construction.
- The Plenty Line
- Supply at least the security strength actually claimed by the chosen algorithm and add a conservative implementation margin.
- Why more is not automatically better
- Entropy beyond the key size cannot make that key stronger; lifecycle, endpoint, and algorithm failures become the limit.
Where it appears
Recognize the pattern.
- 01AES data-encryption keys
- 02disk-encryption master keys
- 03backup-encryption keys
The Plentropy rule
Protect the requirement, then stop.
Supply at least the security strength actually claimed by the chosen algorithm and add a conservative implementation margin.
Once that claim has comfortable evidence and margin, improve the next limiting factor instead of worshipping a larger entropy number.