Here’s a quick guide on how to migrate your GPG keys when switching to a new machine.

Check your existing keys

gpg --list-secret-keys --keyid-format LONG

You will get something like:

sec   ed25519/A3CF82DE09B7541A 2025-07-09 [SC]
      E92F1BAA7D6C3E058F4A8D4BA3CF82DE09B7541A
uid                 [ultimate] Tyler Test <tyler@test.xyz>
ssb   cv25519/7B2ECC4F61D83A95 2025-07-09 [E]

SC means the key can Sign (data/messages) and Certify (confirm another key is legit).
E means the subkey is used for Encryption only.

Exporting your key and transferring it to the new machine

Export your public key:

gpg --export -a <KEY_ID> > gpg.pub

…and your private key:

gpg --export-secret-keys -a <KEY_ID> > gpg.sec

This exports the private key in plain text!

Transfer to the new machine:

scp gpg.pub gpg.sec <IP>:

This will transfer the files to the remote machines home directory. Alternatively you could use an USB stick to transfer the files.

Make sure to shred these files as soon as you move them to the new machine!

shred -u gpg.pub gpg.sec

Import your key on the new machine

gpg --import gpg.pub
gpg --import gpg.sec

The keys are now imported, but are not trusted. You can either export the owner trust from the old machine, or trust them manually using the gpg prompt.

Trusting the keys

On the old machine:

gpg --export-ownertrust > trust.txt

Transfer to the new machine and run:

gpg --import-ownertrust trust.txt

If you have lost access to the old machine or want to setup trust manually, you can type gpg –edit-key key-ID, which will open a gpg prompt gpg> where you just type trust. You will be now asked what level of trust you want:

Please decide how far you trust this user to correctly verify other users' keys
(by looking at passports, checking fingerprints from different sources, etc.)

  1 = I don't know or won't say
  2 = I do NOT trust
  3 = I trust marginally
  4 = I trust fully
  5 = I trust ultimately
  m = back to the main menu

Select 5 for ultimate trust. Ultimate trust is needed because it is your own key, not just any key. You can exit the prompt by entering save. That’s it!