Hacker Public Radio

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We start with
Orwellian depictions of the future
read about in the 1950/60s. Working in the 1970s at companies such as
British Telecom
and the L
urgie
. We hear about
telex
,
mainframes
with
magnetic tape
,
type-writers
, and the upskilling of the workforce by the
labour-exchange
. How did a cold and lack of a home telephone lead to businessmen arriving in a foreign land sans camels? Why were
filing cabinets
replaced by
databases
(or were they)? We hear about gaming from a home made version of
Pong
all the way to
Alone in the Dark
. Then modern times: we hear about some favourite
youtube
streams and discover that living in the 2020s is (just about) possible without a
smartphone
.

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In our next look at the game mechanics for Civilization V we examine several related topics: Diplomacy, Spies, and Religious Pressure. They are all ways to interact with other players without the force of arms being involved. And we will discuss the Diplomatic Victory, which is a new victory type added in Civilization V and can be fun to play.

Playing Civilization V, Part 8 - Diplomacy

Other Players

With other players you have a relationship based on their approach to you. They are:

Neutral – This is not Friendly nor is it Hostile. Trades you make with them will be fair from their point of view

Friendly – They like you, and will accept requests from you more often. Trades will be slightly in your favor from their point of view.

Afraid – This only happens if you have a a very substantial advantage in strength, so this is rare. They will readily accept requests from you, and trades will be in your favor

Guarded – They are suspicious and defensive, and will be more likely to be unfriendly. Trades will be harder to achieve, and favor them rather than you.

Deceptive – They will pretend to be friendly, but they are plotting against you. They may bribe other players to declare war on you. They will not accept requests for help, and trades will be hard to achieve.

Hostile – They hate you, and are completely open about it. Trade deals, if you can get them, will be heavily against you.

War – This means they have decided to go to war with you. But they need the right conditions, so they may pretend to be Friendly, Neutral, Guarded, or Hostile while they wait for those conditions to mature.

These are not set in stone, as you can modify how the other player feels towards you by your actions. If you have friends in common that will improve your relationship, or if you have enemies in common. Agreeing to their requests will also improve things. But if you cannot agree, just say so. The worst negative modifier is when you agree to do something, and then do the opposite. Saying no is also negative, but not as bad. Finally, remember that negatives will erode over time if they are not reinforced. If you want a very detailed look at the mechanics and details of this, check out https://civ-5-cbp.fandom.com/wiki/Detailed_Guide_to_Diplomacy.

City-States

City-States are also important diplomatic partners. We’ll cover all of the benefits in a different section, but here I want to focus on how they enable the Diplomatic Victory. At a certain point the United Nations will be born out of the World Congress, and when this happens a Diplomatic Victory is possible. This will occur when any player reaches the Information Era, or whenever half of the players have reached the Atomic Era. Diplomatic Victory requires that you get the votes of a certain number of delegates to the United Nations. Each player gets delegates based on their population, and there are also some additional delegates you can earn, such as through building the World Wonder Forbidden Palace which gives you two additional delegates. Anyone planning for a Diplomatic Victory should consider building this Wonder as mandatory.

But each City-State gets one delegate, and if you are allied with them their delegate is yours. The mechanics of City-State relationships is that they love gifts, and cash is always the best. So anyone planning a Diplomatic Victory would be well-advised to focus on building a large Treasury. You will know when a World Leader vote is coming up in the United Nations, and can make cash drops on any City-States that are not already allied with you before the vote. But watch out that another player doesn’t do the same thing after you and snipe away some of your allies. Also, you can place your spies in City-States to rig elections, and that is another way to get them to ally with you.

Spies and Espionage

Spies are simply awarded to you whenever any player enters the Renaissance Era. After that you receive another spy each time to advance to another Era. So you can in general have as many as 5 Spies, but if you build the National Intelligence Agency you get one more. This is a National Wonder, and should be a mandatory build if you are going for a Diplomacy victory. And England starts with 1 extra Spy, so if you play as England you could get as many as 7 Spies.

Spies can be used for offense or defense. If you station one of your spies in one of your cities it can operate as a counter-spy, and may thwart or even kill an enemy spy. If you are well ahead in technology, that might be a good use, since other players will be trying to steal your tech. But if you are behind, you might want to use your spies to steal tech from other players. You may be successful in this, but the theft does not go unnoticed, and other player may use one of his spies to counter your operation. If you spy is killed, you will get another one in 3-5 turns, but if your spy was a high-rank spy with promotions, that is a serious loss, so you may want to move that spy elsewhere for a while.

Diplomats

When you assign a spy to the capital of another player you can designate them as a Diplomat. They will take a few turns (depends on game speed, but around 6 turns on normal speeds) to get set up. This is called “Making Introductions”, but the point is that if you need an effective diplomat, don’t wait until the last minute. Diplomats can be useful in several ways. Early on, they allow you to trade votes in the World Congress. And they will bring you intelligence about intrigues, and you can then share that with other players. And it can also give you a view of the other player’s City Screen. Once you have researched Globalization your Diplomats can help with a Diplomatic Victory because each one counts as one additional vote in the United Nations for World Leader.

You can change a spy into a Diplomat and vice versa just by moving the Spy/Diplomat from its current location to another location, which will trigger the ability to change the job assignment. This means that when you first get Spies, and they cannot yet be used to get additional Delegate votes as Diplomats, you can assign them to City-States, where they can help you get alliances. Then as you start to research Globalization, move them to the capitals of other players and turn them into Diplomats. This of course assumes you want to win a Diplomatic victory. If instead you are going for a Science victory and are ahead in Science, it is probably best to station them in your own cities to do counter-intelligence work. If you are ahead in Science, other players will be trying to steal tech from you.

Religious Pressure

If you have researched all of the Piety Social Policy Tree, you will have option to choose a Reformation Belief to add to your religion. One of these, Underground Sect, allows your spies to exert religious pressure against the city they have been sent to. However, this effect is fairly small. If there is not a Follower of your religion in the city, it seems to do nothing. But in combination it can flip cities to your religion. Start by sending in a Missionary to spread your religion, then your spy can add to that. And you should also combine that with a trade route to add additional religious pressure. And by gradually moving your spies, missionaries, and trade routes from city to city, you can make your religion dominant in a region.

Diplomatic Victory

This can be a fun way to win, and I have done it. If you want to get a leg up, start with a Civ that gives you advantages, such as Greece or Venice (although my last diplomatic Victory was achieved with Ethiopia, which is generally regarded as a military/domination Civ. You can win any victory type with any civ, and it can be fun to “play against type”). Greece gets an advantage from relations with City-States, which are key to a Diplomatic Victory because each one gets a vote for World Leader. And Venice is interesting because you cannot build settlers. But you can use cash to puppet City-States, and you can purchase units in puppeted City-States as well. Cash is king in the Venice strategy, and you will want to get as many Trade Routes as possible. The first two should send Food to Venice to help boost your population. Since you will only ever have one city as Venice you will want to max it out. All trade routes after that should focus on cash. Use your cash to purchase or upgrade military units, and employ a defensive strategy. You want enough military to deter any aggression against you, but you should avoid making any hostile moves against others if possible. Remember, this is a strategy for a Diplomatic Victory. If you want to go to war, don’t choose Venice. Instead choose one of the Domination Civs, like the Zulus or the Mongols.

Links:

https://civ-5-cbp.fandom.com/wiki/Detailed_Guide_to_Diplomacy

https://www.palain.com/gaming/civilization-v/playing-civilization-v-part-8/

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Create a Linux kiosk at your library

Start without a guest account

The first few steps of this process don’t actually require a guest user directory to exist, so do NOT create your guest user account yet. However, you do need to choose what your guest user account is going to be called. A reasonable account name for Don’s purposes is libraryguest. On my personal computer I call my guest account guestaccount, and I’ve used kioskguest on some installations. I avoid just the name “guest” because in modern computing the term “guest” gets used in a few other ways (such as a “guest operating system” in a virtual environment), and it’s just easier to find something unique in logs.

Choose a unique name for you guest account, but don’t create it yet. For this article, I’m using libraryguest.

Create the PostSession script

By default, GDM recognises several states: Init, PostLogin, PreSession, and PostSession. Each state has a directory located in /etc/gdm. When you place a shell script called Default in one of those directories, GDM runs the script when it reaches that state.

To trigger actions to clean up a user’s environment upon logout, create the file /etc/gdm/PostSession/Default. You can add whatever actions you want to run upon logout to the Default script. In the case of Don’s library, we wanted to clear everything from the guest’s home directory, including browser history, any LibreOffice files or GIMP files they may have created, and so on. It was important that we limited the very drastic action of removing all user data to just the guest user. We didn’t want the admin’s data to be erased upon logout, so whatever rule we added to /etc/gdm/PostSession/Default had to be limited to the guest user.

Here’s what we came up with:

#!/usr/bin/sh
echo "$USER logged out at `date`" >> /tmp/PostSession.log
if [ "X$USER" = "Xlibraryguest" ]; then
rm -rf "$HOME"
fi
exit 0
The first line is for logging purposes. The /tmp directory gets cleared out on most distributions automatically, so we weren’t worried about creating a file that’ll grow forever and eventually crash the computer. If your distribution of choice doesn’t clean out /tmp automatically, create a cron job to do that for you.

GDM knows what user triggered the logout process, so the if statement verifies that the user logging out is definitely the libraryguest user (that’s the literal name of the user we created for library patrons).
Note that the whitespace around the square brackets is important, so be precise when typing!

As long as it is libraryguest, then the script removes the entire user directory ($HOME). That can be extremely dangerous if you make a mistake, so do thorough testing on a dummy system before implementing a script like this! If you get a condition wrong, you could erase your entire home directory upon logout.

In this example, I’ve successfully limited the rm command to a logout action performed by user libraryguest. The entire /home/libraryguest directory is erased, and the computer returns to the GDM login screen. When a new user logs in, a fresh directory is created for the user.

You can put any number of commands in your script, of course. You don’t have to erase an entire directory. If all you really want to do is clear browser history and any stray data, then you can do that instead. If you need to copy specific configuration files into the environment, you can do that during the PreSession state.

Just be sure to test thoroughly before committing your creation to your users!

What happens when the guest doesn’t log out

At this point, the computer erases all of the user’s data when the user logs out, but a reboot or a shutdown is different to a logout. GDM doesn’t enter a PostSession state after a reboot signal has been received, even if the reboot occurs during an active GDM session.

The easiest and safest way to erase an entire home directory when there’s a cut to system power is to use a temporary RAM filesystem (tmpfs) to house the data in the first place. If the systems you’re configuring have 8 GB or more, and the system is exclusively used as a guest computer, you can probably afford to use RAM as the guest’s home directory. If your system doesn’t have a lot of RAM, then you can use the systemd work-around in the next section.

Assuming you have the RAM to spare, and that your systems are supported by a backup power supply, you can add a tmpfs entry in /etc/fstab. In this example, my tmpfs is mounted to /home/libraryguest and is just 2 GB:

tmpfs /home/libraryguest tmpfs rw,nosuid,nodev,size=2G 0 0
That’s plenty of space for some Internet browsing and even a few LibreOffice documents to be saved while a user works.

Mount the new volume:

$ sudo mount /home/libraryguest
Next, you must create the libraryguest user manually in a terminal.
The useradd command creates user profiles:

$ sudo useradd --home-dir /home/libraryguest libraryguest
useradd: warning: the home directory /home/libraryguest/ already exists.
useradd: Not copying any file from skel directory into it.
Because you’ve already created a location for the home directory, you do get a warning after creating the user. It’s only a warning, not a fatal error, and the guest account is automatically populated later.

Create a password for the new user:

$ sudo passwd libraryguest
That’s it! You’ve created a guest account that refreshes with every logout and every reboot. You can skip over the next section of this article.

Using systemd targets instead of a ramdisk

Assuming you can’t create a ramdisk for temporary user data, you can instead create a systemd service that runs a script when the reboot, poweroff, and multi-user targets are triggered:

[Unit]
Description=Kiosk cleanup
[Service]
Type=oneshot
ExecStart=/usr/local/bin/kiosk-cleanup.sh
[Install]
WantedBy=poweroff.target reboot.target multi-user.target
Save the file to /etc/systemd/system/kioskmode.service and then enable it:

$ sudo systemctl enable --now kioskmode
The script, like the GDM script, removes the libraryguest directory. Unlike GDM script, this one must also recreate an empty home directory and grant it user permissions:

#!/usr/bin/bash
rm -rf /home/libraryguest
mkdir /home/libraryguest
chown -R libraryguest:libraryguest /home/libraryguest
Grant the script itself permission to run:

$ sudo chmod +x /usr/local/bin/kiosk-cleanup.sh
Now the libraryguest user data is erased after:

Logout

Reboot

Shutdown

Startup

Essentially, no matter how the computer loses its session or its power, the libraryguest account starts fresh when a new session is started.

Security and privacy

Using systemd to erase data at shutdown and startup isn’t strictly as secure as using a temporary ramdisk for all user data. Should the computer lose power suddenly, all saved user data in the libraryguest account is present during the next boot. Of course, it’s erased as soon as multi-user.target is called by systemd, but it is technically possible to interrupt the boot process and mine for data. You must use full drive encryption to protect data from being discovered by an interrupted boot sequence.

Why not just use xguest

On many Linux distributions, the xguest package is designed to provide the Guest account, which resets after each logout. It was an extremely useful package that I installed on every machine I owned, because it’s handy to be able to let friends use my computer without risking them making a mess of my home directory. Lately, it seems that xguest is failing to launch a desktop, however, presumably because it relies on X11.

If xguest works for you in your tests, then you may want to use it instead of the solution I’ve presented here. My solution offers a lot of flexibility, thanks to GDM’s autodetection of session states.

Kiosks in libraries

Privacy and personal information is more important than ever. Regardless of how you setup a kiosk for your library, you have an obligation to your users to keep them informed of how their data is being stored. This goes both ways. Users need to know that their data is destined to be erased as soon as they log out, and also they deserve to be assured that their data is not retained.

However, it’s also your responsibility to admit that glitches and exceptions could occur. Users need to understand that the computer they’re using are public computers on a public network. Encryption is being used for traffic and for data storage, but you cannot guarantee absolute privacy.

As long as everyone understands the arrangement, everyone can compute with confidence. Linux, GDM, and systemd are great tools to help libraries create a sustainable, robust, honest, and communal computing platform.

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1985, I started to work at a telecom equipment manufacturer. We
had a main frame computer in our combined office- and lab room. We
were four sitting in the room and it was this one terminal for all
of us and maybe even for someone more.


Downstairs, we at component technology department had our big
climate controlled laboratories. I used an HP 85 computer
having the Basic programming language to automize measurements of
resistors. And there were several more of them for other
measurements of various electronic components. Also more advanced
computers were used in the labs and as I recall also with other
languages than Basic. I remember I learned briefly a bit about one
of those languages but have forgotten which one.


The secretary at the department could send Telex messages around
the world. We handed a hand written manuscript to her and she
typed it into the Telex
system. And she had a Xerox computer with big, at least the
8 inch floppy discs.


Not so many years later my manager got a Personal computer running
DOS and some years later it DOS computers also
to the staff. But also very early we had a Sun Unix station. And
for many years Unix became my daily driver at work.


Before I started to work, in school we had some education in Basic programming.
We were using the at least in Sweden very successful and good Luxor ABC 80
computer. At the end of my school time, my school got the top
notch ABC 800 with colour screen.

At home so I could get a chance to learn somewhat more about
computers and Basic programming in my own pace, I got a Zinclair ZX 80
computer, which I later upgraded to ZX 81.


One summer job when I was a student I was at Televerket,
the Swedish PTT. It meant that I visited numerous of exchange
stations. Many at the country side, some with very few subscribers
so I could hear the relay start when someone was making a call. At
bigger stations it was noise from relays all the time.


As I mentioned, after studies were completed I was working with
telecom equipment in particular for land line telephony. Not at
least I worked with components for the line cards, the card at the
telephone exchange that is facing towards the end user.


The book The_Cuckoo's_Egg is a hacker thriller based on a
true story that happened in the mid-1980's going on for a year. It
was written by the hunter shortly after.


Cliff Stoll describes Unix commands, which are similar to
Linux. He talks about passwords, about encryption and a lot more.
Many technical details he describes by using analogy with more
common non technical life examples.


A security hole in GNU-Emacs
software, a software still around today, plays a central
role in how the hacker could penetrate. To fix and update security
holes are very relevant today as well.


Many things in computers and technology have changed. But at the
same time very much of the problems are valid today although they
are somewhat different. And the way he describes technical details
for the non-technical reader are relevant also today, I believe.


At the same time as the book has many technical details, he also
describes the daily life at home, the left wing culture he
belonged to at the university, his long hair and the dress code he
belonged to. And the music. He also describes his contacts to
numerous authorities and frustration in those contacts. I am very
impressed of his analytical research approach, his persistence,
his skills and inventiveness including inventiveness of his girl
friend and others.


One take away for me is that he kept a detailed log book. It is an
important research tool. The log book together with the print outs
of exactly what the hacker did were core references for analyzing
and make conclusions, retract and change conclusions when new
information lead to that earlier assumptions were wrong.


He also wrote a technical paper about it before he wrote the book.
For those interested, there are several videos with him of later
date on various topics.
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Warning, this episode containers some spoilers for movies.

The following movies are in my cybersecurity movie library. The ones marked * are included in review in this episode.

2001: A Space Odyssey (1968) *

AntiTrust (2001)

Blackhat (2015)

Blade Runner (1982)

Catch Me If You Can (2002)

Citizenfour (2015)

CSI: Cyber (2015)

Enemy of the State (1998)

Firewall (2006)

Gattaca (1997) *

Ghost in the Shell (1995)

Hackers (1995) *

Heartbreakers (2001)

The Imitation Game (2014)

I, Robot (2004)

Johnny Mnemonic (1995)

Jurassic Park (1993) *

The KGB, the Computer and Me (1990) * - Youtube link

The Lives of Others (2006) *

Lo and Behold, Reveries of the Connected World (2016)

The Matrix (1999)

The Matrix Reloaded (2003) *

The Matrix Revolutions (2003)

Minority Report (2002)

Mission: Impossible (1996) *

Mr. Robot (2015)

The Net (1995) *

The Net 2.0 (2006)

Ocean's Eleven (2001)

Office Space (1999) *

Person of Interest (2011) *

Revolution OS (2001)

The Social Network (2010)

Sneakers (1992) *

Superman III (1983) *

Surrogates (2009)

Swordfish (2001)

Takedown (2000)

Tron (1982) *

WarGames (1983) *

Slashdot "Best Hacker movie" poll (August 2001):

https://slashdot.org/poll/683/best-hacker-flick

This episode contains short except clips from some of these movies used under free use for demonstration.

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