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Wakeup Flower

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HSM explained

1. What is an HSM?

  • HSM = Hardware Security Module
  • It’s a physical device (appliance) designed to securely generate, store, and manage cryptographic keys.
  • HSMs are tamper-resistant: if someone tries to tamper with them, the device wipes its contents.
  • AWS offers AWS CloudHSM, which provides dedicated HSMs in the cloud, fully managed by you (not AWS).

2. The Situation

  • If you try to log in as the administrator more than twice with the wrong password, the HSM zeroizes itself.
  • Zeroize = wipes everything (all keys, certs, data).
  • This is a security feature → prevents brute force or unauthorized access.
  • But if it happens accidentally, you lose your keys permanently.

3. Why Amazon Can’t Help

  • Amazon does not have access to your HSM or your credentials.
  • That means if you lose your credentials or the HSM zeroizes, AWS cannot recover your keys.
  • This is by design — for compliance and security reasons (you alone control the keys).

4. The Solution

To avoid losing access to your cryptographic material:

  1. Restrict access via Security Groups
  • Only allow trusted admin IPs to reach your HSM.
  • This prevents random/unauthorized attempts to log in and trigger zeroization.
  1. Use Multiple HSMs in a Cluster
  • Best practice: deploy 2+ HSMs in different Availability Zones (AZs).
  • This ensures redundancy and durability.
  • If one HSM is zeroized, the cluster remains intact because the other HSMs still hold the keys.
  1. Back up your keys securely
  • CloudHSM clusters replicate keys across HSMs automatically.
  • But if all HSMs are zeroized and you have no backup → keys are lost forever.

Key Takeaway

  • HSM = Hardware Security Module → secure key management appliance.
  • Zeroization = wipe everything after failed admin logins.
  • Solution:

    • Restrict access with security groups.
    • Always run multiple HSMs in separate AZs in production.
    • Treat credentials carefully, because AWS cannot recover lost keys.

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