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Format and link fixes in 2020/ferguson2

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To make this easier to see what it all is I'm doing this in a separate
pull request.

Some of the links were broken and I added some links as well. I tried to
only link to the same thing once (per section) but it's possible I
missed some.

Format fixes in some code blocks and probably other things too.

Clarify and reword some things as well.

And _this_ should be the final one for now unless I see a problem on
GitHub (I'll be checking the rendered output of the markdown files and
making any fixes if necessary).
This commit is contained in:
Cody Boone Ferguson committed 2023-04-17 05:18:55 -07:00
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2020/ferguson2/README.md
+247 -191
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@@ -46,7 +46,7 @@ make
```
**NOTE**: in recode no spaces between options and option arguments are allowed.
**NOTE**: in [recode](recode.c) no spaces between options and option arguments are allowed.
## Try:
@@ -94,7 +94,7 @@ do?
## Judges' remarks:
This code is an [enigma](https://en.wikipedia.org/wiki/Enigma_machine). Try to decode it!
This code is an [enigma](https://youtu.be/ybkkiGtJmkM). Try to decode it!
There is a good deal of useful documentation that is provided with this entry:
@@ -104,13 +104,13 @@ There is a good deal of useful documentation that is provided with this entry:
man ./enigma.1
```
* [recode.html][]
- Some useful information about recode.c
* [recode.html][] (or [recode.md](recode.md) if reading on GitHub)
- Some useful information about [recode.c](recode.c)
* [chocolate-cake.html][]
- Because most of us could use some *Double-layered Chocolate Fudge Cake*!
- NOTE: see [recode.html][] for details about how to decrypt this!
* [chocolate-cake.html][] (or [chocolate-cake.md](chocolate-cake.md) if reading on GitHub)
- Because most of us could use some *Double-layered Chocolate Fudge Cake*!
- NOTE: see [recode.html][] (or [recode.md](recode.md) for details about how to decrypt this!
[recode.html]: recode.html
@@ -118,10 +118,8 @@ There is a good deal of useful documentation that is provided with this entry:
## Author's remarks:
My remarks about my [Heer
'Army'](https://en.wikipedia.org/wiki/German_Army_(1935%E2%80%931945) and
[Luftwaffe 'Air Force'](https://en.wikipedia.org/wiki/Luftwaffe) [Enigma
machine](https://en.wikipedia.org/wiki/Enigma_machine) simulator for
My remarks about my [Heer][] (army) and [Luftwaffe][] (air force) [Enigma
machine](https://www.cryptomuseum.com/crypto/enigma/index.htm) [simulator](prog.c) for
the 27th IOCCC.
I want to dedicate this entry in part to the millions of poor souls that were
@@ -136,22 +134,22 @@ makes it somehow even more tragic: there wasn't even a good reason for the war
If one were to write the name of every person who died in the conflict in a
book, it would take so many pages that the book would be so heavy, so long, so
expensive to print, and it wouldn't bring anyone back to life nor would it
erase the suffering. Nothing will. It's horrible.
expensive to print and it wouldn't bring anyone back to life nor would it erase
the suffering. Nothing will. It's horrible.
There really are no words that can truly describe the tragedy but I wish to with
my Enigma simulator honour each and every soul who was lost, or suffered, or
my [Enigma][] simulator honour each and every soul who was lost, or suffered, or
suffered the loss of friends or loved ones, as well as the world itself, in and
from one of the greatest tragedies in the history of mankind.
I will have more information on this entry at
[https://ioccc.xexyl.net/2020/enigma][] after the winning entries have been
published.
I have more information on this entry like the testing procedure at
<https://ioccc.xexyl.net/2020/enigma>.
<a name="toc"></a>
- [IOCCC: an Enigma?](#ioccc)
- [The 1992 Nathan entry](#nathan)
- [The 1992 Nathan Sidwell entry](#nathan)
- [Usage](#usage)
* [Example run](#example)
@@ -166,7 +164,7 @@ published.
- [Bugs, limitations, differences from the real Enigma machines and general notes](#bugs)
- [Adding Kriegsmarine support](#kriegsmarine)
- [Kriegsmarine support?](#kriegsmarine)
- [Portability](#portability)
@@ -181,8 +179,9 @@ sure there are some other words that are equally as valid but I believe 'Enigma'
is a great word nonetheless.
However it's curious that no winning entry has ever been a simulator of the
[German Enigma machine](https://en.wikipedia.org/wiki/Enigma_machine). I'm
actually quite surprised at that because it's such a brilliant piece of
[German Enigma machine](https://en.wikipedia.org/wiki/Enigma_machine). I was
actually quite surprised (though pleased as it gave me the chance to learn about
it and submit and win an entry) at that because it's such a brilliant piece of
engineering of the time even though it had a critical flaw: that no letter could
be itself; this combined with cribs (known or suspected plaintext) - which was
down to carelessness, capturing an Enigma and sometimes settings sheet, as well
@@ -194,10 +193,9 @@ code](https://en.wikipedia.org/wiki/Morse_code) entries is particularly
interesting because that's what the Germans did: the party sending the message
would first set up the machine, write down the letters and then transmit by
[Morse code](https://en.wikipedia.org/wiki/Morse_code) the encoded message. Then
those picking up on the message would note the [Morse
code](https://en.wikipedia.org/wiki/Morse_code), translate it to the alphabet
and then input it into their Enigma machine configured in the same way and thus
have the original message.
those picking up on the message would note the Morse code, translate it to the
alphabet and then input it into their Enigma machine configured in the same way
and thus have the original message.
The [1998 ASCII / Morse code translator][] entry by [Franz van
Dorsselaer](/winners.html#Frans_van_Dorsselaer) prints the Morse code of text;
@@ -206,41 +204,42 @@ Vik](/winners.html#Daniel_Vik) can be used to allow for the actual sound of it.
With my entry we can complete the loop!
### <a name="nathan" href="#toc">The 1992 Nathan entry</a>
### <a name="nathan" href="#toc">The 1992 Nathan Sidwell entry</a>
The author [Nathan Sidwell](/winners.html#Nathan_Sidwell) of the [1992 Worst
Abuse of the Rules][] had this to say about his program:
```
This program is a hello world text encrypter/decrypter. It uses an
enigma (I think) style encryption algorithm, where the encryption
key character is modified by a value, determined from the previous
character. Non-printable characters (those with ASCII values < ' '
or > 0x7e) are passed unaltered, thus any kind of file may be
successfully processed, but if the original is printable, the
processed file will be too. The input is read from stdin, and the
output presented to stdout. The key, a text string, is presented as
a command argument. This is optional, and if omitted, the file is
self-{de,en}crypted. To specify decryption, a "-" should be given
before the key. (Actually encryption and decryption proper inverse
operations, so you can use decrypt to scramble and encrypt to
descramble, if you're perverse.)
```
> This program is a hello world text encrypter/decrypter. It uses an
[enigma](https://www.cryptomuseum.com/crypto/enigma/index.htm) (I think) style
encryption algorithm, where the encryption key character is modified by a value,
determined from the previous character. Non-printable characters (those with
ASCII values `< ' '` or `> 0x7e`) are passed unaltered, thus any kind of file
may be successfully processed, but if the original is printable, the processed
file will be too. The input is read from stdin, and the output presented to
stdout. The key, a text string, is presented as a command argument. This is
optional, and if omitted, the file is self-{de,en}crypted. To specify
decryption, a `-` should be given before the key. (Actually encryption and
decryption proper inverse operations, so you can use decrypt to scramble and
encrypt to descramble, if you're perverse.)
But the Enigma algorithm is more complex than that and my entry can encipher (and
by extension decipher) text in the manner of the Enigma machines of the Army (Heer) and Air
Force (Luftwaffe); the Kriegsmarine 'Navy' was more complex (see section [Adding
Kriegsmarine support](#kriegsmarine) for more information on that.
My entry should also work as a non-military grade Enigma as it by default has an
empty plugboard (they had none). I explain how to set up the simulator later.
But the Enigma algorithm is more complex than that and my entry can encipher
(and by extension decipher) text in the manner of the Enigma machines of the
[Heer][] (army) and [Luftwaffe](https://en.wikipedia.org/wiki/Luftwaffe) (air
force); the [Kriegsmarine](https://en.wikipedia.org/wiki/Kriegsmarine) (navy;
literally `War Nazy`) was more complex (see section [Kriegsmarine
support?](#kriegsmarine) for more information on that.
My entry should also work as a non-military grade Enigma; they had no
[plugboard](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm) and by
default mine is empty. I explain how to set up the simulator later.
[Yusuke Endoh](/winners.html#Yusuke_Endoh) asked the judges and me if the real
1992 entry source was available. Simon Cooper didn't have access to it because
it was before his time in the IOCCC; but before the other judges could answer
[Ilya Kurdyukov](/winners.html#Ilya_Kurdyukov) sent a link to the original 1992
code. As of March 2023 the original before unseen code was published but I leave
this in for historical purposes.
code. As of 4 March 2023 the original before unseen code was published but I
leave this in for historical purposes.
### <a name="usage" href="#toc">Usage</a>
@@ -257,25 +256,30 @@ If you run it like:
It will prompt you for the settings of the machine (example below).
The first group is in the order of rotor (number), ring setting (letter) and
The first group is in the order of
[rotor](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm) (number),
[ring setting](https://en.wikipedia.org/wiki/Enigma_rotor_details#Ring_setting) (letter) and
ring (starting) position (letter). It will do this for the first, second and
then third for each.
Then it will prompt you for the reflector (number). The first one is reflector B
and the second is reflector C.
Then it will prompt you for the
[reflector](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#Reflector) (by number).
The first one is reflector B and the second is reflector C.
Finally it'll prompt you for the plugboard pairs.
Finally it'll prompt you for the [plugboard
pairs](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm).
After that you can input the string and it'll go from there.
#### <a name="example" href="#toc">Example run</a>
BTW: There's a much more entertaining (and delicious) challenge or exercise in
[recode.html][] (markdown version [recode.md](recode.md) if reading on GitHub) (involves
[chocolate-cake.html][]) though one might need a different kind of exercise
after taking up the challenge! :-) These however show the general program as
well as how to use the two winning entries of the Morse code that I referred to
earlier:
[recode.html][] (if you're reading this on GitHub check the
[recode.md](recode.md) file instead); this involves [chocolate-cake.html][] (if
on GitHub see [here](chocolate-cake.md)) though one might need a different kind
of exercise after taking up the challenge! :-) These however show the general
program as well as how to use the two winning entries of the [Morse
code](https://en.wikipedia.org/wiki/Morse_code) that I referred to earlier:
```sh
@@ -327,9 +331,10 @@ If I compile the 2014 entry and copy it to my local directory as
$ echo TEST|./prog |./vik | mplayer -demuxer rawaudio -
```
And you would hear Morse code of the Enigma output of 'TEST' (i.e. `KCWV`)! Or
perhaps not in this case. I'm not sure: I discovered a bug in that entry
(Fedora, CentOS and macOS all affected).
And you would hear [Morse code](https://en.wikipedia.org/wiki/Morse_code) of the
[Enigma](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm) output
of 'TEST' (i.e. `KCWV`)! Or perhaps not in this case. I'm not sure: I discovered
a bug in that entry (Fedora, CentOS and macOS all affected).
For example I can use the syntax provided in the winning remarks along with my
entry to write it to a file. Say:
@@ -364,7 +369,7 @@ TEST
I'm not sure what causes that or if there's a way to fix it but that's the
idea anyway. Neither do I know if the original transcoding is correct.
What if I use the input string 'LEST' instead? In that case it worked fine:
What if I use the input string `LEST` instead? In that case it worked fine:
```sh
$ echo LEST | ./prog | ./vik > lest.raw
@@ -388,7 +393,7 @@ Phew! The program redeemed itself after the test failure! :)
is with some of the things I pasted in the other file and maybe others here
too. Notice also how it showed the same output that my program gave it - `UUMMX`.)
What about the other Morse code entry?
What about the other [Morse code entry](/1998/dorssel/dorssel.c)?
```sh
$ echo IOCCC | ./prog | ./dorssel
@@ -397,10 +402,15 @@ $ echo IOCCC | ./prog | ./dorssel
### <a name="recode" href="#toc">The recode.c configurator</a>
I have included a supplementary program [recode.c][] that can
do a number of things which acts as a kind of wrapper and configurator to my
entry. By default it prompts you for the settings (rotors/rings, ring settings,
positions, reflector and plugboard pairs), validating input as you go.
I have included a supplementary program [recode.c][] that can do a number of
things which acts as a kind of wrapper and configurator to my entry. By default
it prompts you for the settings
([rotors](https://en.wikipedia.org/wiki/Enigma_rotor_details), [rings and ring
settings](https://en.wikipedia.org/wiki/Enigma_rotor_details#Ring_setting) and
positions,
[reflector](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#Reflector) and
[plugboard pairs](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm)),
validating input as you go.
After that it prompts for text that you can pass to the Enigma simulator;
alternatively you can specify a file to read in.
@@ -409,10 +419,10 @@ It has a randomise mode and it can save/read the settings to/from a file to
allow for duplicity (an archaic term for the state of being double but obviously
for Enigma it has to also mean deceitful).
I recommend using this in a pipeline instead of the simulator itself if you want
to change the configuration of the simulator because it offers a much richer
experience (and because you can reuse the configuration without having to type
it out again every time).
I recommend using this in a pipeline instead of the [simulator](prog.c) itself
if you want to change the configuration of the simulator because it offers a
much richer experience (and because you can reuse the configuration without
having to type it out again every time).
It does take the effort to try and prevent invalid input (as above) though maybe
I didn't think of everything. My entry was meant to be a simulator only as far
@@ -427,8 +437,8 @@ For examples using it (and a delicious challenge) see [recode.html][] (or
### <a name="parsersubtlety" href="#toc">A parser subtlety that could cause confusion</a>
The parser is in a sense rather rudimentary but allows for both interactive and
automatic (e.g. via the recode program) input. This does mean that something
like the following can happen:
automatic (e.g. via the [recode](recode.c) program) input. This does mean that
something like the following can happen:
```sh
$ ./prog -
@@ -456,32 +466,37 @@ SIRDK
First of all: what is that `WD`? I didn't type that but it showed up hitting
`ctrl-d` to end input.
If everything is input correctly it would show nothing except the actual Enigma
output (maybe at times ^D - I have noticed this at least when I don't fill in
all plugboard pairs - which might or might not be possible with the Enigma
machines that had plugboards, I really do not know). I don't view this as a bug
because the parsing of input is meant to be simple and in fact you can expect
the same output from the same input even if there are errors in the input.
If everything is input correctly it would show nothing except the actual
[Enigma machine](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm) output
(maybe at times ^D - I have noticed this at least when I don't fill in all
[plugboard](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm) pairs - which
might or might not be possible with the Enigma machines that had plugboards; I
really do not know). I don't view this as a bug because the parsing of input is
meant to be simple and in fact you can expect the same output from the same
input even if there are errors in the input.
Anyway as you can see the first `1AB` was the first ring, setting and position.
After this it wants Ring 2 and I did similar; for ring 3 I did it each variable
by itself. However for the reflector I did `1A` and it only expects 1 char! So will
that mean that the plugboard pairs are off? Yes it does seem to be so. This is
buffering at play I believe but it's useful for allowing the recode program to
easily configure the Enigma machine. In the other markdown/html file I give a hint
as to how this could be fixed but the caveat is it would necessitate a need for
rewriting recode.c.
by itself. However for the reflector I did `1A` but it only expects 1 char! So
will that mean that the plugboard pairs are off? Yes it does seem to be so. This
is buffering at play I believe but it's useful for allowing the `recode` program
to easily configure the Enigma machine. In the [recode.html](recode.html) file
(or [recode.md](recode.md) if reading on GitHub) file I give a hint as to how
this could be fixed but the caveat is it would necessitate a need for rewriting
[recode.c](recode.c).
There's another thing to be aware of and that's the way the ranges are enforced.
There are five rotors which obviously are in C 0-4 but in 'natural language'
1-5 (they were labelled I, II, III, IV and V though).
There are two reflectors and the same applies: in C 0-1 but in human it's
1-2 (technically these were reflectors B and C in the Enigma machine which I
display by name in recode.c just like with the rotors).
There are two
[reflectors](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#Reflector) and the
same applies: in C 0-1 but in human it's 1-2 (technically these were reflectors B and C in
the Enigma machine which I display by name in [recode.c](recode.c) just like
with the rotors).
For more information see [recode.html][] or [recode.md](recode.md) if viewing on
GitHub.
For more information see [recode.html][] (or [recode.md](recode.md) if viewing on
GitHub).
BTW: If you need a reminder to go to the gym just do your Enigma ABCs and it
should help you remember (though not at this time in our world it might help you
@@ -500,26 +515,29 @@ ABC
The layout of [recode.c][] isn't too significant (but see below) but I want to
mention [prog.c](prog.c) especially:
I did think of a more artistic layout but reflecting on it I think that the
blankness of it can be another way of honouring all the many people who died
in - like all other wars - what was a useless conflict because - again like all
other wars - a powerful human being decided that they should rule others.
I did think of a more artistic layout but
[reflecting](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#Reflector)
on it I think that the blankness of it can be another way of honouring all the
many people who died in - like all other wars - what was a useless conflict
because - again like all other wars - a powerful human being decided that they
should rule others.
The blankness is a reflection of the millions of people who died unknown, uncared
for, unloved, without ever being acknowledged in their far too short lives, some
even unidentified; it's the presence of absence.
The blankness is a
[reflection](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#Reflector)
of the millions of people who died unknown, uncared for, unloved, without ever
being acknowledged in their far too short lives, some even unidentified; it's
the presence of absence.
I find it somehow fitting that the day I have finished this is 30 April 2020,
which was exactly 75 years from the day that the person responsible for the
[Second World War](https://en.wikipedia.org/wiki/World_War_II), Adolf Hitler,
ended his life. (I have since then made a bug fix but I consider this
inconsequential).
ended his life. (I later made a bug fix but I consider this inconsequential).
As for [recode.c][] though I really love this:
```c
/\
/ This is *not* what you think:
/\
/ This is *not* what you think:
```
...because it seems so wrong in C code at first glance. Also what does the
@@ -529,9 +547,9 @@ As for [recode.c][] though I really love this:
### <a name="obfuscation" href="#toc">Obfuscation</a>
It's an Enigma simulator! Isn't that proof that it's obfuscated itself?! :)
Silliness aside [obfuscation.txt][] has some of the ways I think this entry is
obfuscated. To decipher try:
It's an [Enigma machine](https://en.wikipedia.org/wiki/Enigma_machine) simulator! Isn't
that proof that it's obfuscated itself?! :) Silliness aside [obfuscation.txt][]
has some of the ways I think this entry is obfuscated. To decipher try:
```sh
./recode -Robfuscation.key -fobfuscation.txt | ./prog - 2>/dev/null > obfuscation.md
@@ -550,8 +568,10 @@ For the lazy [obfuscation.md][] has the deciphered version. I am afraid I'm not
so inclined to do that for the cake recipe: the idea there is to make it a fun
exercise that when solved unlocks a wonderful double-layered chocolate fudge
cake recipe. But given that my ['Don't tread on me'](../ferguson1) award entry
also has the recipe, not enciphered, one might just go there instead. Still it's
a fun way to explore this entry.
also has the [recipe](../ferguson1/chocolate-cake.html)
([ferguson1/chocolate-cake.md](../ferguson1/chocolate-cake.md) if reading on
GitHub), not enciphered, one might just go there instead. Still it's a fun way
to explore this entry.
As for the [obfuscation.key][] file if you observe the contents you'll find the
word `OBFUSCATION`:
@@ -567,16 +587,19 @@ Ways that my simulator differs from the real thing. Not all of these are bugs
and some could be considered features; others are just differences.
* Does not check for using the same rotor more than once. The real Enigma
machines this would not work because they had to choose from a set of rotors and
there were no duplicates. This shouldn't be a problem here however except that
it wouldn't be a possible configuration of the real Enigma machine. The `recode`
program *however does validate this* (except when reading in settings via the
`-R` option which I explain in the [recode.html][]/[recode.md](recode.md) file).
* Does not check for using the same
[rotor](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#Reflector)
more than once. The real Enigma machines this would not work because they had to
choose from a set of rotors and there were no duplicates. This shouldn't be a
problem here however except that it wouldn't be a possible configuration of the
real Enigma machine. The `recode` program *however does validate this* (except
when reading in settings via the `-R` option which I explain in the
[recode.html][] file ([recode.md](recode.md) on GitHub).
* The way the plugboard - for the machines that had them - is if you connect A
to B then no other letters can connect to A or B. Earlier there wasn't proper
detection and this caused invalid output.
* The way the [plugboard](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm)
\- for the machines that had them - is, if you connect A to B then no other
letters can connect to A or B. Earlier there wasn't proper detection and this
caused invalid output.
> Why only 10 pairs when the German alphabet has 26 letters (the Enigma did not
have the Eszett or the umlauts and in any case there is some disagreement about
@@ -585,45 +608,53 @@ letter and for the Eszett you can use 'ss' or 'SS' which is what they did)? It's
theoretically possible to have 13 but the Enigma typically had 10 pairs. It's
easy enough to update my entry to do this once you de-obfuscate it but I'm not
helping there (and in fact I don't think I could any more even if I wanted to -
at least not easily!).
at least not easily).
* It does not obviously have the clicking sound associated with the moving
parts of the real machine. I think it would be annoying to have this as it
processes each letter. However with the Morse code audio transcoder entry you
processes each letter - but with the [2014 Morse audio transcoder][] entry you
can at least have the output played in Morse code as the Germans did; I think
that is really cool (I think it's really cool even if there's a bug in it)! That
that's really cool (I think it's really cool even if there's a bug in it). That
it pays homage to that (and another) entry is a bonus here.
* The simulator doesn't report errors but tries to gracefully deal with them:
if one chooses a value out of range it moves it into the range (if > the max
then the max, if < min then the min). If invalid chars are input for the
* The [simulator](prog.c) doesn't report errors but tries to gracefully deal
with them: if one chooses a value out of range it moves it into the range (if >
the max then the max, if < min then the min). If invalid chars are input for the
plugboard pairs then it's not added to the plugboard etc.
* The real Enigma machines had only letters: no digits, no punctuation. My
entry prints `!isalpha()` chars untouched. The Germans had different systems for
punctuations, numbers etc. (one of the documents I link to has these details).
* The real [Enigma
machines](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm) had
only letters: no digits, no punctuation. My entry prints `!isalpha()` chars
untouched. The Germans had different systems for punctuations, numbers etc. (one
of the documents I link to has these details).
* My entry preserves case of letters. The real Enigma had only one case as it
was just a keyboard and they didn't need case-sensitivity. Context would be
important as some words in German have different meanings depending on if
capitalised or not (and all nouns are capitalised).
* Later models introduced a fourth rotor. The Kriegsmarine procedures were
also far more complex than the Heer and Luftwaffe. I find this particularly
* Later models introduced a fourth rotor. The
[Kriegsmarine](https://en.wikipedia.org/wiki/Kriegsmarine) procedures were
also far more complex than the [Heer][] (army) and [Luftwaffe][] (air force)
(though apparently the additional notch provided another flaw). I find this particularly
interesting because it was Hermann Goering who was the Supreme Commander of the
Luftwaffe and the intelligence agency Forschungsamt (FA) was his; it provided
Hitler with invaluable information so one would think the Luftwaffe system would
be more complex! See [adding Kriegsmarine support](#kriegsmarine) for more
be more complex! See [Kriegsmarine support?](#kriegsmarine) for more
information.
* I only include reflectors B and C. To have included more would have used too
many bytes (each reflector and rotor is 26 characters!) and I could not include
them for this reason; I include 5 rotors and 2 reflectors and that's a total of
(`5 * 26 + 2 * 26` == 182 chars) but there are as you can see many other strings
too. It is however feasible to update the rotor and reflector options and you
could even make your own versions if you wanted to. Doing this is an exercise to
the reader however (the idea of trying this makes me cringe because of how I
obfuscated things including encrypting some of it with the Enigma itself)!
* I only include
[reflectors](https://en.wikipedia.org/wiki/Enigma_machine#Reflector) [B and
C](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#wiringtables).
To have included more would have used too many bytes (each reflector and
[rotor](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#rotors) is
26 characters!) and I could not include them for this reason; I include five
rotors and two reflectors and that's a total of (`5 * 26 + 2 * 26 == 182` chars)
but there are as you can see many other strings too. It is however feasible to
update the rotor and reflectors options and you could even make your own
versions if you wanted to. Doing this is an exercise to the reader however (the
idea of trying this makes me cringe because of how I obfuscated things including
encrypting some of it with the Enigma itself).
There's one thing I'm unsure of in my implementation. Because of all the
possible settings I used some other simulators as a starting point and more
@@ -644,16 +675,20 @@ online simulator so I presume it is correct. It might be that the Germans tended
to have it at A but again I do not know.
### <a name="kriegsmarine" href="#toc">Adding Kriegsmarine support</a>
### <a name="kriegsmarine" href="#toc">Kriegsmarine support?</a>
I said that one could add the additional rotors used by the Kriegsmarine but
looking at this again it appears that it's not as simple as adding the rotors to
the code and updating the references to the array etc.
Is it possible to add [Kriegsmarine](https://en.wikipedia.org/wiki/Kriegsmarine)
support? I thought so by adding the additional rotors but looking at it again it
appeared that it's not as simple as adding the rotors to the code and then
updating the references to the array etc.
This is because [rotors](https://en.wikipedia.org/wiki/Enigma_rotor_details)
`VI`, `VII` and `VII` had two notches and this changes the way things work. The
[Kriegsmarine M4](https://www.cryptomuseum.com/crypto/enigma/m4/index.htm) also
had an additional change which would complicate matters more.
This is because it had three additional
[rotors](https://en.wikipedia.org/wiki/Enigma_rotor_details) - [`VI`, `VII` and
`VII`](https://www.cryptomuseum.com/crypto/enigma/m4/index.htm#wheels) - and had
[two notches](https://en.wikipedia.org/wiki/Enigma_rotor_details#Turnover_notch_positions)
and this changes the way things work. The [Kriegsmarine
M4](https://www.cryptomuseum.com/crypto/enigma/m4/index.htm) also had an
additional change which would complicate matters more.
I looked into trying to do this for another version after winning but some of
the obfuscation techniques dramatically complicates even attempting this so I
@@ -693,47 +728,56 @@ my website) are the same under Fedora, CentOS and macOS.
#### A note on Wehrmacht, its branches and other agencies and their Enigma machines
The Wehrmacht was the defence force in full which included the Heer (army),
Luftwaffe (air force) and Kriegsmarine (navy). As I said the Kriegsmarine
procedures were more complex: they had additional rotors and one of their models
had a different reflector system (thin instead of thick - some of the documents
below discuss this). The military intelligence agency, the Abwehr, had their own
system too. Non-military grade Enigma machines didn't have the plugboard. And
so on.
The [Wehrmacht](https://en.wikipedia.org/wiki/Wehrmacht) was the defence force
in full which included the [Heer][] (army),
[Luftwaffe](https://en.wikipedia.org/wiki/Luftwaffe) (air force) and
[Kriegsmarine](https://en.wikipedia.org/wiki/Kriegsmarine) (navy). As I said the
Kriegsmarine procedures were more complex: they had additional rotors and one of
their models had a different
[reflector](https://en.wikipedia.org/wiki/Enigma_machine#Reflector) system (thin
instead of thick - some of the documents below discuss this). The military
intelligence agency, the Abwehr, had their own system too. Non-military grade
Enigma machines didn't have the
[plugboard](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm). And so on.
However one of the documents below distinguishes the Kriegsmarine from the
Wehrmacht; when you see this you can read it as the Kriegsmarine versus the rest
of the Wehrmacht rather than the Wehrmacht and the Kriegsmarine.
[Enigma Message Procedures][]: The Heer, Luftwaffe and Kriegsmarine Enigma
[Enigma Message Procedures][]: The [Heer][],
[Luftwaffe](https://en.wikipedia.org/wiki/Luftwaffe) and
[Kriegsmarine](https://en.wikipedia.org/wiki/Kriegsmarine))
[Enigma](https://en.wikipedia.org/wiki/Enigma_machine)
procedures.
[Interactive Enigma Machine][]: Shows wiring of the Enigma machine based on the
[Interactive Enigma Machine][]: Shows wiring of the [Enigma
machine](https://en.wikipedia.org/wiki/Enigma_machine) based on the
settings and input (unfortunately uses Flash). This was what I used to verify
output (as best I could find). To set this up to use the default settings in my
simulator make sure to use Rotors I, II and III and the starting positions at B,
B and C respectively (as in left, centre, right). To do this click the button at
the top right that looks like:
simulator make sure to use
[Rotors](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#Rotors)
I, II and III and the starting positions at B, B and C respectively (as in left,
centre, right). To do this click the button at the top right that looks like:
```
o->
<-o
```
And then select the rotors. Next click the button again at the left of the
and then select the rotors. Next click the button again at the left of the
rotor selection 'screen'. Then use the arrow buttons above each rotor to set
from left to right B, B and C. After this you can type your message in the input
field and watch the wiring of the rotors change and show the path it takes.
If I made use of the Enigma code in the recode.c program I would maybe consider
doing something like that but I intentionally do not use it there: as cool as it
might be it would give a better idea of how the algorithm works (unless I were
to make it just as obscure as I do in prog.c but that's also a bit risky). I
don't believe I could do it now anyway.
If I made use of the Enigma code in the [recode.c](recode.c) program I would
maybe consider doing something like that but I intentionally do not use it
there: as cool as it might be it would give a better idea of how the algorithm
works (unless I were to make it just as obscure as I do in prog.c but that's
also a bit risky). I don't believe I could do it now anyway.
I'm uncertain how to change the rotor settings itself in this simulator to
determine if the ring settings being different from ABC would cause a problem
I'm uncertain how to change the rotor setting itself in this simulator to
determine if the ring settings being different from `ABC` would cause a problem
(this is the thing I mention I'm uncertain about in the bugs section).
Going back to the configuring the online simulator try inputting the text IOCCC
@@ -744,21 +788,26 @@ UUMMX
```
Which is exactly as my entry shows! So at least for the starting position `BBC`
and an empty plugboard and the other defaults in my entry (which appear to be
consistent with the online simulator too) I can verify it works.
and an empty [plugboard](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm)
and the other defaults in my entry (which appear to be consistent with the
online simulator too) I can verify it works.
[Tony Sale's pages on The Enigma cipher machine][]: This is many pages on the
Enigma machine by the late Tony Sale who was the original curator of the
Bletchley Park Museum. There is a wealth of information in these pages on how
the Enigma worked and this includes some challenges to do to see how well you
understand the algorithm.
[Bletchley Park Museum](https://www.cryptomuseum.com/bp/). There is a wealth of
information in these pages on how the Enigma worked and this includes some
challenges to do to see how well you understand the algorithm.
Fun fact: the abbreviation for the Signals Intelligence is that of our
wonderful SIGINT.
Fun fact: the abbreviation for the [Signals
Intelligence](https://en.wikipedia.org/wiki/Signals_intelligence#World_War_II)
is that of our wonderful `SIGINT`.
[Technical Details of the Enigma Machine][]: 'This page provides the technical
details of the Wehrmacht and Luftwaffe Enigma, and the Kriegsmarine Enigma M4.'
It is quite a nice document with diagrams, pictures of actual Enigma rotors and
details of the [Wehrmacht](https://en.wikipedia.org/wiki/Wehrmacht) and
[Luftwaffe](https://en.wikipedia.org/wiki/Luftwaffe)
[Enigma](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm), and the Kriegsmarine Enigma M4.'
It is quite a nice document with diagrams, pictures of actual Enigma
[rotors](https://www.ciphermachinesandcryptology.com/en/enigmatech.htm#Rotors) and
other parts and more.
[The German Enigma Cipher Machine][]: The history of Enigma, its development,
@@ -793,23 +842,27 @@ that.
[Technical Details of the Enigma Machine]: https://web.archive.org/web/20200710094303/http://users.telenet.be/d.rijmenants/en/enigmatech.htm
[The German Enigma Cipher Machine]: https://web.archive.org/web/20200710094243/http://users.telenet.be/d.rijmenants/en/enigma.htm
[How the Enigma was Set Up and Operated]: http://www.ellsbury.com/enigma3.htm
[https://ioccc.xexyl.net/2020/enigma]: https://ioccc.xexyl.net/2020/enigma
## Author's dedication:
### <a name="winning" href="#toc">Winning thoughts, dedications and thanks</a>
Once again I'm honoured to win along with some of the other veterans who I have
a huge amount of respect for; there's Don Yang, Dave Burton, Yusuke Endoh and
Edward Giles all of whom are amazing programmers. I'm especially proud to win
besides Dave Burton and Yusuke Endoh but Don Yang and Edward Giles too.
a huge amount of respect for; there's [Don Yang](/winners.html#Don_Yang), [Dave
Burton](/winners.html#Dave_Burton), [Yusuke Endoh](/winners.html#Yusuke_Endoh)
and [Edward Giles](/winners.html#Edward_Giles) all of whom are amazing
programmers. I'm especially proud to win besides Dave Burton and Yusuke Endoh
but Don Yang and Edward Giles too.
But there are some others who I don't remember like Ilya Kurdyukov (who's
offered a lot of interesting thoughts on Snake and who plans to have his own
version after the entries are published), Nathan Otterness, Nicholas Carlini
(whose entry is an absolutely brilliant abuse of printf - and I totally agree
with the judges remarks that your entry is so novel that it'll be worth special
mention in the future Best of IOCCC list!) and tsoj too.
But there are some others who I don't remember like [Ilya
Kurdyukov](/winners.html#https://en.wikipedia.org/wiki/Signals_intelligence#World_War_II)
(who's offered a lot of interesting thoughts on [Snake](../ferguson1/prog.c) and
who plans to have his own version after the entries are published), [Nathan
Otterness](/winners.html#Nathan_Otterness), [Nicholas
Carlini](/winners.html#Nicholas_Carlini) (your entry is an absolutely brilliant
abuse of `printf` - and I totally agree with the judges remarks that your entry
is so novel that it'll be worth special mention in the future Best of IOCCC
list!) and [tsoj](/winners.html#_tsoj) too.
Well done and congratulations to all of you again! Thank you for submitting the
wonderful entries and I'm honoured to have my two entries beside yours!
@@ -828,16 +881,14 @@ mother.
I also want to dedicate this to Vicky Wilmore who has given me a lot of
love the past few years and who was there for me in some very dark times. Thank
you Vicky sweetheart from the bottom of my heart and soul. Although we have
parted ways, whether for now or for ever, you will always always always have a
place in my heart and soul xxx
you Vicky sweetheart from the bottom of my heart and soul xxx
Once more besides those two I want to also dedicate this to all the many
millions of people whose lives were taken from them in what amounts to - like
all other wars - a horrible, pointless conflict and an utter waste of life,
something precious that is far too often taken for granted. As I noted before I
found it fitting that I finished this on 30 April 2020 - exactly 75 years after
Adolf Hitler, he who started the [Second World War]([Second World
Adolf Hitler, he who started the [Second World
War](https://en.wikipedia.org/wiki/World_War_II), ended his life. The blankness
of the layout is another way of honouring the poor souls who lost their lives,
many of whom we will never know even their name let alone what they might have
@@ -845,11 +896,12 @@ accomplished if it wasn't for their tragic and pointless deaths. Always remember
that life is precious and never ever take it for granted! Believe in yourselves.
Everyone. Do not let anyone ruin that for you ever.
I would like to thank my dear friend Martijn Schoemaker for encouraging me in my
programming over the years and who I owe a great deal to. Thank you for
believing in me and my programming abilities (and other abilities) even when I
couldn't believe in myself! Very much appreciated especially coming from an
amazing programmer who I have huge admiration for!
I would like to thank my dear friend [Martijn
Schoemaker](https://www.ficture.nl) for encouraging me in my programming over
the years and who I owe a great deal to. Thank you for believing in me and my
programming abilities (and other abilities) even when I couldn't believe in
myself! Very much appreciated especially coming from an amazing programmer who I
have huge admiration for!
Finally I want to thank Leo Broukhis, Simon Cooper and Landon Curt Noll for
continuing to hold the contest after all these years - and for having selected
@@ -858,6 +910,10 @@ as well as the award titles. And yes indeed 'most of us could use
*[Double-layered Chocolate Fudge Cake][]*!'
[Double-layered Chocolate Fudge Cake]: chocolate-cake.html
[Heer (army)]: https://en.wikipedia.org/wiki/German_Army_(1935%E2%80%931945)
[Heer]: https://en.wikipedia.org/wiki/German_Army_(1935%E2%80%931945)
[Luftwaffe]: https://en.wikipedia.org/wiki/Luftwaffe
[Enigma]: https://www.cryptomuseum.com/crypto/enigma/index.htm
## Copyright and CC BY-SA 4.0 License:
2020/ferguson2/recode.md
+25 -23
View File
@@ -1,13 +1,14 @@
# The recode configurator documentation (and a fun way to explore my 2020 IOCCC Enigma simulator)
N.B. At the end of this file I have given a fun exercise that can be used to
explore my [Enigma machine](https://en.wikipedia.org/wiki/Enigma_machine)
simulator. It's especially worth doing if you you like good chocolate and could
explore my [Enigma machine](https://www.cryptomuseum.com/crypto/enigma/index.htm)
[simulator](prog.c). It's especially worth doing if you you like good chocolate and could
use a delicious [Double-layered Chocolate Fudge Cake][].
Alternatively if you just want the [recipe](/2020/ferguson1/chocolate-cake.md)
Alternatively if you just want the [recipe](../ferguson1/chocolate-cake.md)
you could look at my [Snake entry 'Don't tread on me'
award](/2020/ferguson1/prog.c) since it's also there and not enciphered.
award](../ferguson1/prog.c) since it's also there and not enciphered.
<a name="toc"></a>
@@ -115,9 +116,8 @@ Though you won't find some of those strings in [recode.c](recode.c) or
amusing coincidence *but it really did happen!*
As for `-f` the contents would be output with the settings e.g. to pipe to
[prog](prog.c) itself (as if you redirected the file contents to the Enigma
machine for encipherment/decipherment). If the file cannot be opened it sets
back to stdin.
`prog` itself (as if you redirected the file contents to the Enigma machine for
encipherment/decipherment). If the file cannot be opened it sets back to stdin.
`-o` outputs the settings to the file. If the file cannot be opened for writing
or is the same file name (see below) then only stdout will be used. Example of
@@ -166,7 +166,7 @@ argument) shell expansion will not work right so for example doing:
$ ./recode -R~/config
```
Will not read the file 'config' in the home directory. I show another way to
will _not_ read the file 'config' in the home directory. I show another way to
achieve this later.
This limitation also applies to the `-f` and `-o` options!
@@ -263,11 +263,11 @@ Input plugboard pair 10: QR
```
Notice that I skipped a [plugboard
pair](https://en.wikipedia.org/wiki/Enigma_machine#Plugboard); this can be done
in a number of ways but two dots is one. Notice also that it's in a different
order than the simulator: because with the size restrictions on my entry I saved
bytes by using the same loop where I could. It just felt more natural to have
them grouped together in a configurator for the simulator.
pair](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm); this can be done in
a number of ways but two dots is one. Notice also that it's in a different order
than the simulator: because with the size restrictions on my entry I saved bytes
by using the same loop where I could. It just felt more natural to have them
grouped together in a configurator for the [simulator](prog.c).
```sh
$ echo 1AA2AA3AA2ABCD..EFGHIJKLMNOPQRIOCCC | ./prog - 2>/dev/null
@@ -292,6 +292,7 @@ the pipeline works with settings etc.
What happens if the plugboard pairs are the same but in a different order? It's
the same output:
```sh
$ echo 1AA2AA3AA2AB..CDEFGHIJKLMNOPQRIOCCC|./prog - 2>/dev/null
HQNVO
@@ -356,9 +357,10 @@ Plugboard pair #10: ST
```
Notice that I redirect stdout to /dev/null so that the config is only written to
the file config. But also notice that for plugboard pair 4 I typed in `GHIJ` and
it didn't report an error. Neither did it complain about `IJ` in the next pair.
This is because it consumes input overflow.
the file config. But also notice that for [plugboard
pair](https://www.cryptomuseum.com/crypto/enigma/i/sb.htm) 4 I typed in `GHIJ`
and it didn't report an error. Neither did it complain about `IJ` in the next
pair. This is because it consumes input overflow.
It shouldn't be this way for the simulator though because that could cause
inconsistent number of characters expected before the text to encipher.
@@ -394,8 +396,8 @@ $ ./recode -r -osettings
(Above ^D was not shown but I typed it.) The way it works: if nothing is read
the buffer remains `NULL` and so I don't print it but still do print the settings
file. Actually even if `getdelim()` fails you're supposed to free the buffer so I
set another variable to indicate if it should be printed.
file. (Actually even if `getdelim()` fails you're supposed to free the buffer so I
set another variable to indicate if it should be printed.)
# <a name="reuseconfig" href="#toc">Reusing a configuration</a>
@@ -504,7 +506,7 @@ UGEVP
```
Note that I typed in IOCCC and sent EOF (ctrl-d); the settings were written to
Note that I typed in `IOCCC` and sent `EOF` (ctrl-d); the settings were written to
the config file (for deciphering later) and then all of it was piped to the
Enigma entry resulting in the line below IOCCC. But let's verify it worked out
okay:
@@ -560,7 +562,7 @@ anyway?
* Best idea: try the below experiment!
# <a name="cake" href="#toc">Delicious Enigmatic: Double-layered Chocolate Fudge Cake</a>
# <a name="cake" href="#toc">Deliciously Enigmatic: Double-layered Chocolate Fudge Cake</a>
As I was making the above silly list something occurred to me. My [other
entry](/2020/ferguson1/prog.c) this year includes a recipe for a wonderful
@@ -571,9 +573,9 @@ So this is what I offer: if you take one of the settings below and run the
simulator on the file [chocolate-cake.html][] you will have a wonderful
chocolate cake recipe (that even my late stepmum who didn't even like chocolate
loved - it's a speciality of my mum's and they were the best of friends too). If
you're lazy just go and look at the
[recipe](/2020/ferguson1/chocolate-cake.html) (or
[here](/2020/ferguson1/chocolate-cake.md) if on GitHub) in my other entry. Then
you're lazy (or just want some delicious double-layered chocolate fudge cake!)
just go and look at the [recipe](../ferguson1/chocolate-cake.html) (or
[here](../ferguson1/chocolate-cake.md) if on GitHub) in my other entry. Then
again if you're lazy you're probably not reading this far! :)
The settings is one of the below but a couple questions you might ask yourself: