Fixing unknown public key

While installing a package from AUR I got the following error:

FAILED (unknown public key 2E1AC68ED40814E0)

The fix was to download the public key with gpg:

$ gpg --recv-key 2E1AC68ED40814E0
gpg: /home/mike/.gnupg/trustdb.gpg: trustdb created
gpg: key 93298290: public key "Tor Browser Developers (signing key) <>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg:               imported: 1