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SSH Medium · Lesson 1 · On the house

Certificates concept

Short-lived SSH certs instead of forever keys. Lesson 1 is free — on the house.

Lessons · SSH Medium · Lesson 1 of 10 · On the house

Certificates concept

Short-lived SSH certs instead of forever keys.

Illustration for SSH
Lesson 1 is on the house.

SSH certificates are keys signed by an SSH CA for hosts or users.

Servers trust the CA; clients present user certs with expiry and principals.

Short TTLs reduce the blast radius of stolen credentials.

Host certificates stop TOFU prompts in fleets when clients trust the host CA.

Operational tooling issues and renews certs — treat the CA as critical infrastructure.

certs

# Concept: ssh-keygen -s ca -I id -n principals user_key.pub → user-key-cert.pub
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Quiz

An SSH user certificate is?

Quiz

Why short-lived certs?

Quiz

Host certificates help clients?

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