GPG Quickstart

GPG (GNU Privacy Guard) Quick Start

Installation and Setup:

Install GnuPG on Archlinux
```
sudo pacman -S gnupg
```
Adjust Permissions for GPG Home Directory:
```
chmod 0700 ~/.gnupg/
```
Customize GPG Home Directory (Optional):
```
export GNUPGHOME=/tmp/gnupg
```

Key Management

Check Existing Keys:
```
gpg --list-keys
```
Generate New Key Pair:
```
gpg --full-generate-key
```

Generating a Key Pair with Specific Expiry Date:

gpg --full-generate-key --expire-date YYYY-MM-DD

Generating a Key Pair with Specific Parameters:

gpg --full-generate-key --default-key-algo rsa4096

Managing Subkeys:

List subkeys:

gpg --list-secret-keys --with-subkey-fingerprints

Add subkey:

gpg --edit-key [email protected]
addkey

Update Key Expiration Date:
- Changing Expiry Date:
```
gpg --edit-key [email protected]
expire
```

Adding or Changing Passphrase:

gpg --edit-key [email protected]
passwd

Create Revoke Certificate (GnuPG < 2.1):

gpg --output [email protected] --gen-revoke [email protected]

# Revoke the key with this revoke certificate generated above
gpg --import [email protected]

Revoking a Key:

gpg --edit-key [email protected]
revkey

Setting Key Trust Level:

gpg --edit-key [email protected]
trust

Removing a key from the public keyring
```
gpg --delete-keys [email protected]
```
Removing a key from the secret keyring

!! UNSAFE, BE CAREFUL !!
```
gpg --delete-secret-keys [email protected]
```

Searching, Importing and Exporting GPG Keys

Searching for a GPG Key on a Keyserver:
```
gpg --search-keys [email protected]
```
Importing a GPG Key from a Keyserver:
```
gpg --recv-keys KEY_ID
```

Export Public Key to file:

gpg --export --armor [email protected] > public_key.gpg
gpg --export --armor --output [email protected] [email protected]

Exporting Your Public GPG Key to Send to Another User:

gpg --export --armor --output your_public_key.gpg YOUR_EMAIL

Sending Your Public GPG Key to a Keyserver:

gpg --list-keys --keyid-format LONG YOUR_GPG_EMAIL
gpg --send-keys YOUR_KEY_ID_FROM_ABOVE

Importing Another User’s Public GPG Key from a File:
```
gpg --import their_public_key.gpg
```

Exporting Private Key to file:

gpg --export-secret-keys --armor [email protected] > private_key.asc

Importing Private Key from file:
```
gpg --import private_key.asc
```

Encrypting and Decrypting Files

Encrypting a File:

gpg --encrypt --recipient [email protected] file.txt

Decrypting a File:

gpg --decrypt file.txt.gpg > decrypted_file.txt

Encrypting and Decrypting Files with Symmetric Encryption:
- Encrypting:
```
gpg --symmetric file.txt
```
- Decrypting:
```
gpg --decrypt file.txt.gpg
```

Encrypting for Multiple Recipients:

gpg --encrypt --recipient [email protected] --recipient [email protected] file.txt

Encrypting a File with Multiple Passphrases:

gpg --symmetric --cipher-algo AES256 --recipient [email protected] --recipient [email protected] file.txt

Encrypting and Signing Messages:

gpg --sign --encrypt --armor --recipient [email protected] file.txt

Decrypting a File and Verifying Signature:

gpg --decrypt file.txt.gpg | gpg --verify file.txt.sig

Generating a Random Password with GPG:
```
gpg --gen-random --armor 1 12
```

Signing and Verifying

Signing a File:
```
gpg --sign file.txt
```
Verifying a Signature:
```
gpg --verify file.txt.sig
```

Configuration

Setting Preferences for Keyserver:

nano ~/.gnupg/gpg.conf
# Add/edit the line:
# keyserver hkps://keys.openpgp.org

Key Backups :

Regularly back up both public and private keys to prevent loss.
Backup entire directory: cp -r ~/.gnupg/ /path/to/backup/location
Backup private key only: gpg --export-secret-keys --output [email protected] --armor [email protected]

GPG Quickstart

GPG (GNU Privacy Guard) Quick Start

Installation and Setup:

Install GnuPG on Archlinux

Adjust Permissions for GPG Home Directory:

Customize GPG Home Directory (Optional):

Key Management

Check Existing Keys:

Generate New Key Pair:

Generating a Key Pair with Specific Expiry Date:

Generating a Key Pair with Specific Parameters:

Managing Subkeys:

Update Key Expiration Date:

Adding or Changing Passphrase:

Create Revoke Certificate (GnuPG < 2.1):

Revoking a Key:

Setting Key Trust Level:

Removing a key from the public keyring

Removing a key from the secret keyring

Searching, Importing and Exporting GPG Keys

Searching for a GPG Key on a Keyserver:

Importing a GPG Key from a Keyserver:

Export Public Key to file:

Exporting Your Public GPG Key to Send to Another User:

Sending Your Public GPG Key to a Keyserver:

Importing Another User’s Public GPG Key from a File:

Exporting Private Key to file:

Importing Private Key from file:

Encrypting and Decrypting Files

Encrypting a File:

Decrypting a File:

Encrypting and Decrypting Files with Symmetric Encryption:

Encrypting for Multiple Recipients:

Encrypting a File with Multiple Passphrases:

Encrypting and Signing Messages:

Decrypting a File and Verifying Signature:

Generating a Random Password with GPG:

Signing and Verifying

Signing a File:

Verifying a Signature:

Configuration

Setting Preferences for Keyserver:

Key Backups :