Pretty Good Privacy

Perhaps inspired by upcoming events, I decided to get things in place to facilitate secure communications with my compatriots.  After spending years considering various options, I’ve settled on The GNU Privacy Guard (GPG), an open-source implementation of the OpenPGP standard .

Many systems offer secure communications but most rely on services or software which belong to, or run on, third-party systems.  Most of these systems are in turn owned by private corporations.  Regardless of how thick your tinfoil hat is, even under the best of circumstances these companies can be bought, sold or simply fail, which leaves your ability to communicate (and the privacy of your previous communications) in a dubious position.  OpenPGP -based privacy is a bit more effort, but all you need to use it is a personal computer and the GPG software, which runs on almost any working computer you can find.

First, some nomenclature:

  • OpenPGP is a standard that defines the way data is encrypted and decrypted, and how the associated keys, identities, etc.

  • GPG is an implementation of the OpenPGP standard, a piece of software that can be used to encrypt and decrypt messages.

  • A public key is something you can share openly with people you want to communicate securely with

  • A private key is something you use to decrypt encrypted data sent to you, and you must keep it secret

Besides GPG, there are other implementations of the OpenPGP standard.  Any piece of software that implements the standard can decrypt data encrypted by another, so long as the proper keys are in place.  So, if your friend uses a commercial encrypted email package that uses OpenPGP-compliant encryption, you can read their messages using GPG and vice-versa.

Using GPG

There’s a wide-range of tools designed to make using GPG easier, but I recommend starting with the basic command-line tools so that you have a more complete understanding of what’s going on.  One of the key problems with creating secure communications is the ability to loose track of what’s happening to the information you want to secure.  Once the cat is out of the bag, you can’t put it back in.

I won’t go into great detail about setting up GPG, plenty of other people who know a lot more about have done so already (I’ll provide some links below). What I will describe are the steps involved in sharing an encrypted document with a college so you can get a feel for what’s involved.

A very common situation where you need to encrypt information is when you want to share account information with someone else*.  How this is often done is by writing down the information and sharing it in person, or sending the user name and password via separate means.  In both these cases, the credentials are potentially stored somewhere along the way, which makes them vulnerable. On the other hand, if you use OpenPGP, you can encrypt a file containing the account information and share it via any means you like with no fear of it revealing the secret information.

So for example, let’s say I want to share my Netflix account with a trusted friend; here’s how I would do it:

First I create a file containing the user name & password for my account:

Second, I encrypt this file specifically for my friend:

gpg –output netflix.txt.gpg –encrypt –recipient ralph@nader.org netflix.txt

Finally, I email the encrypted file.

When my friend receives the email, he downloads the attached file, and decrypts it

gpg –output netflix.txt netflix.txt.gpg

Then he can watch some shows, change my credit card information or sell the account to the Russians**

At this point you might be asking “How come Jason’s friend can decrypt the file but random Internet people can’t?” .  This is where the “trusted friend” part comes into play.

Before you can share an encrypted file with someone, you will need their public key.  Once you have someone’s public key, you can add it to your GPG keychain and create encrypted files which can only be decrypted by the intended recipient.  This is what is meant by a “trusted friend”.

It’s worth pointing out that it’s not necessary for both parties to share keys in order to send a message.  Since there is no harm in sharing public keys, many people include their public keys in email and other communication, or post them on their websites, etc.  If, for example, you wanted to send a secure message to a reporter and they share their public key on their blog, you can add that key to your keychain, encrypt a message for only that person and safely send it over the Internet.  If the reporter decides to reply to you, they may request your public key in order to encrypt the response so that only you can read it, but this isn’t a prerequisite for you to send the initial message.

It’s worth pointing out again that you need to protect your private key.  If anyone were to get a hold of it, they can decrypt any data that you ever encrypted with the key.  There are numerous ways to avoid this, or to minimize the damage if it happens, but the important thing is that you are aware of how critical it is to keep your private key private.

Conversely you need to keep track of the private key as well, because if you loose it, you can no longer decrypt any data that was encrypted with the key. Arguably this is better than someone else getting access to your private key, but not much better.

Used correctly, OpenPGP is extremely effective at keeping secrets.  Possibly more important than the encryption itself is the fact that communicating securely using OpenPGP relies only on the two trusted parties involved in the conversation.  It does require some premeditation in order to establish trust, and that’s not necessarily a bad thing, but that means it’s a good idea to get things setup before you need them.

There is a common misconception that encryption is only needed by criminals or perhaps the press or the government, but as you can see from the example above, there are everyday situations where having the ability to send private information between trusted individuals is handy and necessary.  We tend to delegate responsibility for our privacy to others and expect them to provide secure means of communication, but with OpenPGP we can guarantee privacy ourselves to a degree far beyond what is possible by depending on an outside entity, company, etc.

If you’d like to get started using GPG here’s a few links to more detailed information.  If you’d like to send me an encrypted message to test your setup, I’ve included my public key below.

My public key, should you like to get in touch:

-—-BEGIN PGP PUBLIC KEY BLOCK—–
Version: GnuPG v1
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=Oeiz
-—-END PGP PUBLIC KEY BLOCK—–

  • It goes without saying that sharing accounts is in general a bad idea, but there are times when it’s necessary.

**This raises an important point about using encryption.  Even though the data is secure in transit, once it’s decrypted anyone can use it, so it’s important that the people you share with understand this and don’t store this decrypted information in vulnerable places.


evernote

1293 Words

2016-08-16 00:00 +0000