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Instructions for exporting/importing (backup/restore) GPG keys

Every so often I have to restore my gpg keys and I'm never sure how best to do it. So, I've spent some time playing around with the various ways to export/import (backup/restore) keys.

Method 1

Backup the public and secret keyrings and trust database

cp ~/.gnupg/pubring.gpg /path/to/backups/
cp ~/.gnupg/secring.gpg /path/to/backups/
cp ~/.gnupg/trustdb.gpg /path/to/backups/
# or, instead of backing up trustdb...
gpg --export-ownertrust > chrisroos-ownertrust-gpg.txt

NOTE The GPG manual suggests exporting the ownertrust instead of backing up the trustdb, although it doesn't explain why.

Restore the public and secret keyrings and trust database

cp /path/to/backups/*.gpg ~/.gnupg/
# or, if you exported the ownertrust
gpg --import-ownertrust chrisroos-ownertrust-gpg.txt

Method 2

This only really works if you don't mind losing any other keys (than your own).

Export public and secret key and ownertrust

gpg -a --export > chrisroos-public-gpg.key
gpg -a --export-secret-keys > chrisroos-secret-gpg.key
gpg --export-ownertrust > chrisroos-ownertrust-gpg.txt

Import secret key (which contains the public key) and ownertrust

gpg --import chrisroos-secret-gpg.key
gpg --import-ownertrust chrisroos-ownertrust-gpg.txt

Method 3

This is mainly about trusting my key once I've imported it (by either restoring the pubring.gpg and secring.gpg, or by using --import). This seems to be what I do the most as I either forget to import the trustdb or ownertrust.

Ultimately trust the imported key

This is so that I can encrypt data using my public key

gpg --edit-key
gpg> trust
Your decision? 5 (Ultimate trust)

NOTE If I don't trust the public key then I see the following message when trying to encrypt something with it:

gpg: <key-id>: There is no assurance this key belongs to the named user

Regarding the trustdb vs ownertrust export thing: the GPG manual actually does explain why --export-ownertrust is preferred, albeit on a different page:

This is useful for backup purposes as these values are the only ones which can't be re-created from a corrupted trustdb.

jeifour commented Jul 31, 2015

I still don't understand why this would be better over backing up the trustdb. The trustdb should only be corrupted if the backup is corrupted, I would assume. And if the backup is corrupted, the ownertrust.txt export would also be corrupted.

The trustdb should only be corrupted if the backup is corrupted, I would assume.

Not necessarily. The ownertrust export stores the values in plain text form (fingerprint:level), while trustdb don't. It could be corrupted because of GPG version incompatibilities and a number of other reasons.

r5d commented May 31, 2016 edited

Wrote a script to automate the backup. It is at

Tzeejay commented Sep 13, 2016

Thanks for collecting this, and to everyone else for the thoughtful conversation.

xuhdev commented Feb 11, 2017

Is method 2 a superset of method 1? Seems method 1 is only one step in method 2.

Any ideas why importing ownertrust from file gives me gpg: error in 'myownertrustfile.txt' line too long ?

Very good! Thanks!

cmcginty commented Sep 15, 2017 edited

You can simplify Method 3 a little by extending the command to:

gpg --edit-key trust quit

There is also a way to run the command in a non-interactive mode:

expect -c "spawn gpg --edit-key trust quit; send \"5\ry\r\"; expect eof"
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