GNU Privacy Guard

GNU Privacy Guard (GPG or GnuPG) is a open source replacement for the original Pretty Good Privacy software suite. It is capable of encrypt and decrypt data.

Creating a New Key

To generate a new key, run gpg --gen-key

# gpg --gen-key
gpg (GnuPG) 1.4.19; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Please select what kind of key you want:
   (1) RSA and RSA (default)
   (2) DSA and Elgamal
   (3) DSA (sign only)
   (4) RSA (sign only)

Changing Private Key Passphrase

$ gpg --edit-key [keyID]
Command> passwd
Enter passphrase: 
Enter the new passphrase for this secret key.
Enter passphrase:
Repeat passphrase:
Command> save

Exporting Public Key

gpg --armor --export leo@steamr.com --output leo.steamr.pub

Automating Encrypted Backups using Asymmetric Keys

#!/bin/sh

HOSTNAME=`hostname`
DATE=`date +%Y-%m-%d`

# Get the public key to encrypt with
wget -O - http://leo.home.steamr.com/public/backup_key.pub | gpg --import

# Create archive, pipe to gpg to encrypt, then send to freebsd
tar -czpf - \
        /usr/share/sickbeard/ \
        /etc/init.d/sickbeard  \
        \
        /usr/share/SABnzbd/ \
        /etc/init.d/SABnzbd  \
        \
        /home/rt \
        /var/www/html/rutorrent \
        /usr/lib64/httpd/modules/mod_scgi.so \
        /etc/httpd/conf.d \
        /etc/httpd/conf/httpd.conf \
        \
        /etc/fstab \
        /etc/passwd \
        /etc/group \
        /etc/shadow \
| gpg --encrypt --yes --no-tty --trust-model always --recipient leo@steamr.com \
| ssh backup@freebsd "cd /storage/backups/archived/sickbeard; cat - > $HOSTNAME.$DATE.tar.gz.gpg"

# Requires mailx, with smtp=smtp://mail.home.steamr.com set in /etc/mail.rc
echo -e "Backup Completed on `date`.\nUptime: `uptime`\n\nProcesses:\n`ps -eaf`" | mail -s "Backup Completed on `hostname`" "leo@home.steamr.com"

# delete the public backup key
gpg --batch --yes --delete-key leo@steamr.com