Get the fingerprint of a key

Definitions

The fingerprint of a key is a sequence of 40 (2×5×4) hexadecimal digits that identifies the key. The fingerprint is typically printed in 10 (2×5) groups of 4 digits, with two spaces between the 5th and 6th group and a single space between the other groups.

The short key ID of a key consists of the last 8 digits of the fingerprint. The long key ID of a key consists of the last 16 digits of the fingerprint.

Uses

You can use the fingerprint of a key to tell GPG which key in your keyring you mean in a command (especially if you have multiple keys for the same name or email address).

You can also use the fingerprint of a key to check with someone else if you both have the same key (e.g. when signing it). Don’t use short or long key IDs for this. There have been cases where someone has generated a fake key with the same key ID as another key in order to mimic it. I don’t know of any cases where this has been accomplished with full fingerprints.

Get the fingerprint

List the keys in your keyring along with their fingerprints with “gpg --fingerprint”. On my system, “gpg -k” and “gpg -K” give the fingerprints too, but without spaces.

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