docs: add GPG cheatsheet

README.md

@@ -108,6 +108,7 @@ Reference provides cheat sheets for the following:
   involved in using the command line program grep and assumes you already understand its usage.
 - [Netcat](https://cheatsheets.zip/nc.html): This cheat sheet provides various for using netcat on both Linux and Unix.
 - [Taskset](https://cheatsheets.zip/taskset): This quick reference cheat sheet for tasket command.
+- [GnuPG](https://cheatsheets.zip/gnupg): A cheatsheet for GnuPG, the encryption and signing software.
 </details>
 
 <details>

source/_posts/gnupg.md

@@ -0,0 +1,230 @@
+---
+title: GnuPG
+categories:
+  - Linux Command
+intro:
+  A cheatsheet for GnuPG, the encryption and signing software.
+---
+## Getting Started
+
+### Software
+
+Gpg4win and the GPG Suite have OS-specific features.
+
+* [GnuPG](https://gnupg.org/)
+* [Gpg4win](https://www.gpg4win.org/) (Windows)
+* [GPG Suite](https://gpgtools.org/) (macOS)
+
+Sometimes GPG keys are referred as PGP keys. They're interchangeable, as they follow the [OpenPGP Standard](https://www.rfc-editor.org/rfc/rfc9580.html).
+
+### Create a key-pair
+
+Generate your keys:
+
+```shell script
+$ gpg --generate-key
+```
+
+... or fully configure your keys.
+
+```shell script
+$ gpg --generate-full-keys
+```
+
+**Note:** Choose a strong passphrase! The encryption is only as strong as your passphrase.
+
+### Key management
+
+List your keys:
+
+```shell script
+$ gpg --list-keys
+```
+
+List your secret keys:
+
+```shell script
+$ gpg --list-secret-keys
+```
+
+Export your public key:
+
+```shell script
+$ gpg --export --armor <ID>
+```
+
+Export your secret key:
+
+```shell script
+$ gpg --export-secret-key --armor <ID>
+```
+
+Delete your public key:
+
+```shell script
+$ gpg --delete-key <ID>
+```
+
+Delete your secret key:
+
+```shell script
+$ gpg --delete-secret-key <ID>
+```
+
+## Encryption
+
+### Symmetric
+
+Encrypt with a passphrase:
+
+```shell script
+$ gpg -c <FILE>
+```
+
+Encrypt as ASCII with `-a` flag:
+
+```shell script
+$ gpg -ac <FILE>
+```
+
+Set output file path with `-o` flag:
+
+```shell script
+$ gpg -c <FILE> -o <PATH>
+```
+
+Decrypt with a passphrase:
+
+```shell script
+$ gpg <FILE>
+```
+
+**Note:** Choose a strong passphrase! The encryption is only as strong as your passphrase.
+
+### Asymmetric
+
+Encrypt using public-private key encryption:
+
+```shell script
+$ gpg -e -r <RECIPIENT> <FILE>
+```
+
+Encrypt as ASCII output with `-a` flag:
+
+```shell script
+$ gpg -ea -r <RECIPIENT> <FILE>
+```
+
+Encrypt and sign with `-s` flag:
+
+```shell script
+$ gpg -se -r <RECIPIENT> <FILE>
+```
+
+Add multiple recipients:
+
+```shell script
+$ gpg -e -r <RECIPIENT1> -r <RECIPIENT2> <FILE>
+```
+
+Set output file path with `-o` flag:
+
+```shell script
+$ gpg -e -o <PATH> -r <RECIPIENT> <FILE>
+```
+
+Decrypt with your private key:
+
+```shell script
+$ gpg <FILE>
+```
+
+Replace `<RECIPIENT>` with your intended recipient's [imported public key](#importing-a-public-key) ID.
+
+### Importing a public key
+
+Import using a file:
+
+```shell script
+$ gpg --import <FILE>
+```
+
+Import using a link (macOS/Linux):
+
+```shell script
+$ curl <WEBSITE> | gpg --import
+```
+
+Don't forget to sign the imported key:
+
+```shell script
+$ gpg --sign-key <ID>
+```
+
+## Commit Signing
+
+### Local Git Setup
+
+Enable GPG signing:
+
+```shell script
+$ git config --global commit.gpgsign true
+```
+
+Set the signing key:
+
+```shell script
+$ git config --global user.signingkey <ID>
+```
+
+Set location of GPG:
+
+```shell script
+$ git config --global gpg.program <PROGRAM>
+```
+
+**Note:** Your name and email must match on Git and GnuPG.
+
+### GPG Program List
+
+Replace `<PROGRAM>` with one of the following:
+
+| Platform    | Value                                      |
+| ----------- | ------------------------------------------ |
+| Windows     | `C:\Program Files (x86)\GnuPG\bin\gpg.exe` |
+| macOS/Linux | /usr/local/bin/gpg                         |
+
+{.left-text}
+
+### Exporting your public key
+
+Export as ASCII:
+
+```shell script
+$ gpg --export --armor <ID>
+```
+
+**Note:** Platforms, like GitHub, may ask you to verify the email you set in Git and GnuPG.
+
+## Windows: Add to Startup Apps {.cols-1}
+
+### PowerShell Commands
+
+When you do a full restart, the GPG agent might not automatically start. Add
+the GnuPG's IPC tool to Startup Apps using PowerShell:
+
+```shell script
+$ $shell = New-Object -ComObject WScript.Shell
+$ $shortcut = $shell.CreateShortcut("C:\Users\$($Env:UserName)\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\gpg-connect-agent.lnk")
+$ $shortcut.TargetPath = "C:\Program Files (x86)\GnuPG\bin\gpg-connect-agent.exe"
+$ $shortcut.Arguments = "/bye"
+$ $shortcut.Save()
+```
+
+Start up manually instead:
+
+```shell script
+$ gpgconf --launch gpg-agent
+```
+
+Check if it was successfully added [here](ms-settings:startupapps).