Backup and restore¶

This document describes how to backup and restore keys in Pico HSM using wrapped keys. The procedure is based directly on the official Pico HSM documentation.

Backup and restore operations allow exporting keys encrypted under a Device Key Encryption Key (DKEK), ensuring that private keys are never exposed in plaintext.

Overview¶

The backup and restore mechanism relies on:

A Device Key Encryption Key (DKEK)
Wrapped key export
Controlled key import on compatible devices

Warning

Backup data must be protected carefully. Anyone with access to the wrapped keys and the DKEK may restore them.

Generate DKEK shares¶

The DKEK is split into multiple shares using an n-of-m scheme.

Generate the DKEK shares:

pkcs11-tool \
  --generate-key \
  --key-type aes:32 \
  --label dkek \
  --id 01 \
  --pin 648219

Export the DKEK shares:

pkcs11-tool \
  --export-key \
  --id 01 \
  --pin 648219 \
  --output-file dkek-share.bin

Note

The DKEK itself never leaves the device unencrypted.

Backup (export) keys¶

To backup a private or secret key, export it wrapped under the DKEK.

pkcs11-tool \
  --export-key \
  --id 12 \
  --wrap \
  --wrapping-key 01 \
  --pin 648219 \
  --output-file key-backup.bin

This produces an encrypted backup file.

Tip

Store backup files offline and protect them with the same care as the original device.

Restore (import) keys¶

To restore a previously backed-up key:

pkcs11-tool \
  --import-key \
  --unwrap \
  --wrapping-key 01 \
  --pin 648219 \
  --input-file key-backup.bin \
  --id 12 \
  --label restored-key

If the DKEK matches, the key will be restored securely.

Key compatibility¶

Backup files can only be restored:

On devices with compatible firmware
Using the same DKEK
With matching cryptographic capabilities

Warning

Restoring keys on incompatible devices may fail or result in unusable keys.

Security considerations¶

When using backup and restore:

Limit access to DKEK shares
Avoid storing backups online
Test restore procedures before relying on backups

Danger

Loss of both the device and the DKEK makes key recovery impossible.

Summary¶

The backup and restore mechanism in Pico HSM provides:

Secure encrypted key export
Controlled key import
Protection against plaintext key exposure

This enables safe key migration and disaster recovery when used correctly.