This post will describe what hardware to buy & how to configure it so that you have 2 wireless networks in your house: One that seamlessly forces all of the traffic on that network through a VPN–and one that connects to the Internet normally . When finished, the internet activity for any device connected to the first network will be entirely encrypted so that the ISP cannot see which websites are visited*, what software you use, and what information you send & receive on the internet.
* Assuming your config doesn’t leak DNS; see improvements section
Update 2017-08-25: Added “kill switch” firewall rule that prevents LAN traffic from escaping to the ISP unless it passed through the VPN’s vtun0 interface first. Following this change, if the VPN connection is down, the internet will not be accessible (as desired) over the ‘home’ wifi network (without this, the router bypasses the VPN by sending the packets straight to the ISP–giving a false sense of privacy).
This post attempts to answer the following question: If an evesdropper intercepts a message encrypted with gpg, how much information will they be able to extract from the message without a decryption key?
I will show the unencrypted metadata added to a GPG-encypted message, and I will present commands that can be used to extract this unencrypted metadata.
Michael Altfield
Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡
I came back from my “cross-country bicycle trip”:http://1guy2biketrips.michaelaltfield.net to discover I could no longer send signed email because my key expired! I’ve also changed colleges from “SPSU”:http://www.spsu.edu/ to “UCF”:http://www.ucf.edu, and my old college is expiring my email address, so here’s what I need to do:
# Extend my key’s expiration another year # Add new email address to subkey # Save updates to key # Export a new public key
Background Information GPG
“GPG (GNU Privacy Guard)”:http://www.gnupg.org/ (used here) is a popular, cross-platform implementation of “OpenPGP (Pretty Good Privacy)”:http://en.wikipedia.org/wiki/Pretty_Good_Privacy defined in “RFC 4880”:http://tools.ietf.org/html/rfc4880. OpenPGP outlines a standard, open message format for maintaining the “confidentiality”:http://en.wikipedia.org/wiki/Information_security#Confidentiality and “integrity”:http://en.wikipedia.org/wiki/Information_security#Integrity of electronic messages.
Why Subkeys?
“Public Key Cryptography”:http://en.wikipedia.org/wiki/Public-key_cryptography is long, complicated, and well outside the scope of this post. However, one thing I never fully understood was the functional purpose of subkeys. Thankfully, “the GPG documentation”:http://www.gnupg.org/gph/en/manual.html is excellent.
So, there’s 2 major things I want to accomplish by using GPG with my email
# Confidentiality through encryption # Integrity through signatures
The designers of PGP viewed the signature role as indefinitely important while the encryption role as dynamic overtime. Therefore, when we first generate a keypair, 2 keys are created: 1 primary key for . . . → Read More: Extend GPG Key Expiration
Plausibly deniable encryption is a fascinating concept. For example, “TrueCrypt”:http://www.truecrypt.org/ (a FOSS for hard disk encryption) has a wonderful “Hidden Volume”:http://www.truecrypt.org/docs/?s=hidden-volume feature that provides “Plausible Deniability”:http://www.truecrypt.org/docs/?s=plausible-deniability. The concept is: you install 2 OS instances on your computer–1 in a hidden volume. If, for whatever reason, you were forced to reveal your encrypted data, you could give access to decrypt your fake, but seemingly legitimate, OS instance. If done correctly, this could prevent you from forfeiting your sensitive data.
What if you want to encrypt some data to a file, bury it on a thumbdrive somewhere, and make it appear to be just an obscure filetype (possibly corrupted)? I ran across “the answer”:http://old.nabble.com/Is-it-possible-to-decide-what-is-a-gpg-file–td26392408.html when studying for my Secure Computing final.
I haven’t had a chance to research this potential solution, but there seems to exist a project that builds onto the Blowfish cypher to achieve this plausibly deniable encryption: “Blowfish Updated Re-entrant Project (BURP)”:http://www.geodyssey.com/.
Exerpt from “burp.txt”:http://www.geodyssey.com/cryptography/burp.txt
Unlike many similar programs, BURP writes to the output file only the ciphertext (i.e., it writes no “file headers”, password verification data, system, program or content identification strings, etc.). Consequently, such file can not be “provably” identified as ciphertext, as long as the key . . . → Read More: Plausibly Deniable File Encryption
I recently reformatted my hard drive–switching from pure Gentoo to the Sabayon fork. Sabayon did for Gentoo what Ubuntu did for Debian. It’s generally a lot easier to use, but–unlike Ubuntu–it doesn’t sacrifice functionality for ease-of-use.
Michael Altfield
Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡
