Games Worth Playing

Games are a helpful way to keep your audience engaged, and to gently introduce them to technical concepts. It’s unrealistic, and probably not useful, to try to provide a detailed description of how the Internet works in the time you’ll most likely have. Instead, the games below will give your participants an intuitive understanding of basic networking concepts and the role that encryption plays in securing their communications - and hopefully add a little fun to your training sessions!

Cell phone game (generally for 10+ people)

Ask for volunteers to be cell towers, and get them to stand up.

Depending on the size of the room, ask for one or two volunteers to be cell phones. Ask the towers to spread themselves evenly around the room. Ask the cell phones to go to opposite sides of the room, or one side if you only have one cell phone.

Explain the rules thusly: When you call stop, the cellphones stop, and say loudly, “Where am I?”

The closest tower responds: “Marco”

The second closest tower responds: “Polo”

The third closest tower responds: “is a very interesting historical figure”

(Alternate for non-native English speakers: “Ping” “Pong” “is a game with two players”)

Ask the cell phones to walk towards each other, or to the other side of the room, if there’s only one cell phone. Quickly call “Stop!” Encourage anyone who is confused, and help them with any of the steps they are having problems with. It’s normal for there to be some confusion on this iteration, especially for the person who must say “-is a very interesting historical figure.” This is normal and desirable, as this is an engagement exercise as well as a technical one.

Once everyone has stepped through one iteration, stop the game and explain: Each cell phone tower has a circle around it that represents its range. Once you’ve checked in with three towers you know that the cell phone is within the overlap of the three towers. This creates a point that lets the towers know that a cell phone was in a place, at a time – also called “triangulation”. Point out that this isn’t surveillance, or something that companies or governments decided, this is how the physics of radio waves work. This is a good time to make it clear that if your phone is on, and working as a phone, the time and location must be known. Physics, not policy.

You should take this as a chance to explain that systems of surveillance are often built on top of how things just work in the real world. Moreover, that most of the surveillance systems people are worried about are built on top of the first and most prevalent form of infrastructure surveillance – billing systems. You can point out that while this is simplified, it is analogous to how cell phones work, checking in and using time and location data to handle connectivity.

Ask the cell phones to start walking again. Before they meet, call stop. Go through a second iteration, helping anyone confused or having problems as either a cell phone or a tower. Once the second iteration is done, show how two points make a line, and begin to construct path data. Walk the path of one of the phones to point it out.

Let the phones start walking again, meet, and do a third iteration when they meet. This shows they occupy the same point now. After the third iteration, ask the phones to walk away together. Depending on how it’s going, you may or may not want to do another iteration, but at this point you can explain that two paths met and went on together, showing how the data looks to the tower/telecom perspective.

Thank the towers and cell phones, if it’s a big room it’s fun to clap for them, and ask everyone to sit down again.

Packet switching/passing notes in class (Not easily playable with fewer than 6 people)

Materials: notes made out with To and From fields as well as a message, pen or pencil. (Pre-populate the notes with something funny or cute.)

This is an exercise that can be modified and extended throughout trainings to build new ideas on top of the basics of network architecture.

Start with a diagram or picture of a packet switching network, such as the example below: _images/ch1-2-packets.jpgDiagram of a Packet Switching Network - ]

Explain that the node on the end breaks the message into pieces, then passes the pieces to the node it thinks will get the message closer to the destination. That node hands the packet to the next that seems like it might be closer, and so on until it gets to the end point it was intended for. The destination node reassembles the message, and voila! The internet magic happens. This system is more like passing notes in an 8th grade classroom than anything else.

Ask for a volunteer source and destination. If people don’t immediately volunteer, threaten to call on them, establishing yourself as the putative 8th grade teacher. Once you have your two volunteers, write their names on the from and to fields of the small note. Give the note to the source, and tell the room they have to pass the note to the destination without getting caught. Turn your back so they can get started passing the note. Turn back and patter a bit about networks, keeping an eye on the room. Try to catch them at the note passing, and fail. Once the note reaches its destination ask that person to raise the message, demonstrating they got it.

If the message is going by a circuitous route, it’s fun, and true, to note that happens on the internet as well.

Once the note passing is complete, ask everyone who saw the note to raise their hands. Once their hands are up, ask what the problems are with a packet switching network. Discuss the fact that everyone on the network has the chance to see, and even modify the note. For example, one of the evil 8th-graders could change the name of a crush and ruin the rest of the semester for someone. Bring it back to the internet, pointing out that people can read and change messages on a packet switching network.

Packet switching/passing notes in class with encryption variations

Materials: notes with messages, envelopes with To and From fields, pen or pencil. (Pre-populate the notes with something funny or cute.)

Keep or return to a packet switching network image.

_images/ch1-2-packets.jpgDiagram of a Packet Switching Network - (]

After you’ve run the first variation of passing notes in class, you can relax the pretense of teacher (though it may be fun to keep it up, depending on the audience) and begin to add layers.

Many kids started to encode messages in school, so you can point out that encoding messages helps solve all the problems the room identified in the first iteration of the game. An encoded message not only can’t be read, it can’t be altered, which may be even more important for news organizations. This time you can create the message, but then use the envelopes for one of two variations (you may want to do both, and not in this order):

  • End-to-end encrypted message
  • Server side encrypted message

End-to-end encrypted message variation:

Ask for two volunteers, and put them on the to and from field of the envelope. Give the envelope to the sender, and have them put the message in it, and seal it. The envelope here represents mathematical computer encoding, aka encryption. The rule this time is that only the receiver has the power to open the envelope. Begin the note passing again. If you’re still playing teacher, you can try to catch them at it with threats of detention. Either way, don’t direct the note, let the class route it themselves. If it’s taking a long time, you can admonish them humorously for being a slow and clunky connection without good routing, while pointing out that this sometimes happens on the internet too. (Your class cannot make a mistake that doesn’t also happen on the internet. The internet has all the problems.) When the note arrives, tell the recipient to open the envelope and take out the message.

Ask the room to raise their hand if they saw the message. Only the sender and receiver should raise their hands. Then ask them to raise their hands if they saw the envelope, so that the whole route taken should raise their hand now. Ask them what the term is for what they saw. They should answer metadata without too much coaching. Ask them further what metadata they know about that exchange. They will come up with to and from, but keep fishing. They should also arrive at the time of the class, and the people who handled the envelope. If you’ve got someone very on the ball they might say that it was passed in an envelope, which segues easily into detecting protocols and encryption on the net.

Server side encrypted message variation:

You should start this game by pointing out everyone in the room has a gmail account (if people protest that they don’t, remind them that Google has all their mail anyway, since everyone they mail has a gmail account). Ask for a volunteer to be Google. Often one of the more tech-savvy participants will volunteer. After that, ask two more volunteers to play sender and receiver. Importantly, in this variation you will need two identical copies of the message, and two envelopes: the first one to Google from the sender, and the second one marked from Google to the receiver. The rule in this variation is that the message must always go through Google to get to its destination. Give Google the second “From Google” envelope before note passing begins, and put the two copies of the message into the first envelope and seal it, writing the from on it. Begin passing the first envelope, and go stand by Google. Once the envelope reaches Google, tell them to open it up, take out both messages, keep one of them, and put the other into the destination envelope and reseal it.

You can write “HTTPS” on the envelopes in the Google variation to prime the room for talking about SSL/TLS, the protocols commonly used to encrypt Internet communications including web traffic and email.

Now, pretend to be a European or the American government, someone that has the ability to compel Google with a lawful order. Walk over to your Google volunteer, and make a show of being friendly, then asking to see the copy of the message Google has. Google will usually agree and hand it over, but if your Google volunteer doesn’t, ramp up the playful threats (seizing assets, arresting employees, etc.) until they hand it over. Make a show of reading it and hand it back.

Iterating on these exercises

You can follow these variations by combining them, putting another envelope inside the TLS/SSL HTTPS envelope that your Google volunteer has to be put into the envelope to the destination volunteer. You can either leave them with a “cyphertext” version or nothing, so that when you return as the government, you are frustrated by Google not having the message to show you. This presages a discussion of encrypted messaging, including Off-The-Record (OTR) protocol used by some chat apps, and double ratchet protocols such as that used by Signal Messenger. In all cases, you can demonstrate that the To: and From: data is preserved by Google, or potentially by the transiting network itself, for whatever part isn’t covered by TLS.

Tor note passing variation

Materials: Three nesting envelopes, one message (content isn’t important.) Largest envelope should be addressed to “Node 1”, second largest, addressed to “Node 2”, smallest addressed to “Node 3”.

This exercise demonstrates the basic concept of the Tor network. Before you start, ask for a show of hands of people who know what Tor is. If your participants aren’t familiar with Tor, spend a little time describing the system to them before getting started.

Ask for five volunteers: Someone to play “the internet” (”Who wants to be the internet?!”) Someone to play the Tor user, and three to play Tor relay computers. Number your Tor node volunteers 1, 2, and 3, and make a point that the other term for Node 3 is the exit node.

Give the supplies to the Tor user, and instruct them to put the message in the smallest envelope, and seal it. Then that envelop into the second envelope, and so on, until the user is holding the envelope addressed to Node 1 with all the other materials stuffed and sealed into it. Instruct the notes to pass to Node 1, and when Node 1 gets it, have them open the envelope and pass it to Node 2. As Node 2 opens the envelope from Node 1, point out that all Node 2 knows it who the first node was, and who the next node is; this is the “magical” step of Tor, since no one can know both where the message came from and where it’s going, as well as what it is, after this point. Node two passes the smallest envelope to Node 3, who opens it, and then passes it to “the internet”.

Ask what the problem is now, but also what this system is accomplishing (in short, neither Node 3 or the internet can figure out where the message came from, but they can see what the message is, without a further layer of encryption using one of the two models we’ve talked about in previous note passing exercises)

More games to use in training

These are great road tested games for teaching networking principles. If you’re looking for more ideas for games trainers play, check out: