emcomm-tools-os-community/overlay/etc/skel/Desktop/offline/crypto/gpg-cheatsheet.md

title, date, updated, author, categories, tags, copyright

title	date	updated	author	categories	tags	copyright
GNU Privacy Guard: Crypto Cheetsheet	2026-03-19	2026-03-19	The Tech Prepper	cryptography	gpg pgp	(C) 2026 The Tech Prepper, LLC

This is an in-progress cheatsheet for performing basic cryptographic functions using GNU Privacy Guard (gpg), including encrypting, decrypting, and verifying files in an offline environment.

Add Key

Import a public key into your keyring.

1. Download the public key from the trusted individual. It can be saved anywhere. For ease of backup, save them under ~/keys/. Create this directory if it does not exist in your home directory.

2. Import the key file.

   gpg --import KEYFILE

3. Verify the key fingerprint. Your trusted source should provide you with the fingerprint.

   gpg --fingerprint

4. Optionally, edit the key and set the trust level. See the "Set Trust Level" section.

List Keys

List the current public keys on your system.

gpg --list-keys

• pub - Primary key
  • Your identity (root of trust)
  • Used for signing and certifying other keys
• sub - Subkey
  • Used for specific operations (usually encryption)
  • Can be replaced or rotated without changing identity
  • Can be revoked or rotated if compromised
• [SC] - Sign + Certify
• [E] - Encrypt
• unknown|full|ultimate - See "Set Trust Levels"

List the current private keys on your system.

gpg --list-secret-keys

Create Key

gpg --full-generate-key

Encrypt File

gpg -e -r RECIPIENT file.txt

Decrypt File

gpg -d file.txt.gpg

Verify Signature

gpg --verify file.sig file.txt

gpg --verify file.asc

Set Trust Levels

Here are common trust levels for basic use:

• unknown - No trust assigned (default)
• full - You trust this person to sign other keys
• ultimate - Your own key

Perform the following steps to change the trust level for a key.

1. List the keys and identify the key ID (KEYID).

   gpg --list-keys

2. Replace KEYID with the key ID to edit.

   gpg --edit-key KEYID

3. Type trust and press [ENTER].

4. Type the number for the desired trust level and press [ENTER].

5. Type quit to exit.