gnupg.md

title	category	layout	tags	updated	weight	intro
GnuPG	CLI	2017/sheet		2017-10-22	0	[GnuPG](https://gnupg.org/) is a complete and free implementation of the OpenPGP standard.

Basics

Exporting keys

gpg -o key.gpg --export <KEY ID>

Export key in ASCII:

gpg -o key.asc --armor --export <KEY ID>

Note: Omitting the -o|--output option will print the key to stdout.

Importing keys

gpg --import key.gpg
gpg --import key.asc

Only merge updates for keys already in key-ring:

gpg --import key.asc --merge-options merge-only

Managing your keyring

Generate a new key: {: .-setup}

gpg --gen-key
# or, generate a new key with dialogs for all options
gpg --full-gen-key

List public keys:

gpg -k
gpg --list-keys

List secret keys:

gpg -K
gpg --list-secret-keys

Using a keyserver

Import keys from keyserver: {: .-setup}

gpg --receive-keys <KEY IDS>

Upload keys to keyserver:

gpg --send-keys <KEY IDS>

Request updates from keyserver for keys already in your keyring:

gpg --refresh-keys

Search keys from keyserver:

gpg --search-keys "<SEARCH STRING>"

Override keyserver from ~/.gnupg/gpg.conf

gpg --keyserver <URL> ...

Trusting a key

gpg --edit-key <KEY ID>
# In the interactive prompt:
gpg> sign
gpg> save

NOTE: You can use the owner's email or name (or part thereof) instead of the key ID for --edit-key

Encrypting

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Public key encryption

This will produce an encrypted file, secret.txt.gpg, that can only be decrypted by the recipient:

gpg -e -o secret.txt.gpg -r <RECIPIENT> secret.txt

For <RECIPIENT> you can use their key ID, their email, or their name (or part thereof).

gpg -e -r <KEY ID> ...
gpg -e -r "Bez" ...
gpg -e -r "[email protected]" ...

Specifying multiple recipients

gpg -e -r <RECIPIENT> -r <ANOTHER RECIPIENT> ... secret.txt

NOTE: Omitting -o|--output will produce an encrypted file named <ORIGINAL FILENAME>.gpg by default.

Symmetric encryption

Encrypt file using a shared key. You will be prompted for a passphrase.

gpg --symmetric secret.txt
# or
gpg -c secret.txt

Decrypting

{: .-one-column}

Decrypting a file

gpg -d -o secret.txt secret.txt.gpg

If the file is encrypted via symmetric encryption, you will be prompted for the passphrase.

NOTE: Omitting -o|--output will print the unencrypted contents to stdout

Signing & Verifying

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Signing

gpg -o signed-file.txt.gpg -s file.txt

This can be used during encryption to also sign encrypted files:

gpg -s -o secret.txt.gpg \
  -r <RECIPIENT> secret.txt

Verifying a signature

gpg --verify file.txt.gpg

Viewing content of signed file

gpg -d signed-file.txt.gpg

Miscellaneous

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Components

List all components: {: .-setup}

gpgconf --list-components

Kill a component:

gpgconf --kill <COMPONENT> # i.e. gpgconf --kill dirmngr

Kill all components:

gpgconf --kill all

Parsing keyring data

Use --with-colons to produce an output that can easily be parsed i.e. with awk, grep. Fields are colon-separated.

gpg -k --with-colons

Field Quick Reference:

| Field # | Description | | 1 | Record type | | 2 | Validity | | 3 | Key length in bits | | 4 | Public key algorithm | | 5 | Key ID | | 6 | Creation date | | 7 | Expiry date | | 8 | Certificate S/N, UID hash, trust signature info | | 9 | Ownertrust | | 10 | User ID | | 11 | Signature class | | 12 | Key capabilities | | 13 | Issuer fingerprint | | 14 | Flag field | | 15 | S/N of token | | 16 | Hash algorithm | | 17 | Curve name | | 18 | Compliance flags | | 19 | Last update timestamp | | 20 | Origin |

See GnuPG Details for more details.