Author:

• Name: Nathan Sidwell
  Location: GB - United Kingdom of Great Britain and Northern Ireland (United Kingdom)

To build:

    make all

There is an Alternate version which is what was originally published. See Alternate code below for more information.

To use:

    ./nathan
    # enter some text

Try:

To see some other fun uses:

    ./try.sh

Alternate code:

At the time of publication, the judges could not publish the code due to the US export control over encryption. The code that was published would, if run, allow one to get the instructions of how to receive (via email) the actual entry. However, on Sat Mar 4 20:09:35 2023 UTC, the previously unseen code was published. This meant that the old code was not set to compile via the Makefile. This alternate code is that previous version.

Alternate build:

     make alt

Alternate use:

    ./nathan.alt

IMPORTANT NOTE: it is unknown if the email in the code is still valid and as one does not need to email the author for the submitted code one should not email it. In other words, please do NOT send such an email.

Judges’ remarks:

WARNING:

The judges make no claim as to the strength or security of this program. It is likely to be nil, or the next best thing to it. Still, you might consider installing it in /usr/games/nathan. :-)

Note from the judges about the winning category:

The ‘winning’ category is also open to question. One could say that it is a ‘file obfuscator’. One could also say that it unintentionally abused the intent of rule #7 (that programs should be freely re-distributable). We suspect that the author may not have intended to do this, but that is the way things go sometimes.

BTW, ‘abuse of the rules’ entries do not violate the rules. Entries that violate the rules are disqualified. Abuse of the rules entries are ones that tend to ‘stretch’ the limits and take the contest into unexpected territory.

Historical notes from the judges about this entry:

The US International Traffic in Arms Regulations controls certain exportations going out of the United States. The U.S. Munitions List gives the specific categories of restricted exports. Because this entry at one time appeared to fall under this restricted category, the judges originally were not able to distribute some winning entries outside of the US.

Nathan Sidwell stated that he was willing to distribute the winning source. To read HIS instructions of how to obtain his winning program one was able to run:

    make nathan
    ./nathan

to learn how to get a copy of the code.

When someone compiled and ran the code as originally distributed (see: nathan.orig.c the code printed the following message (sic):

Export of this program from the USA is governed by the US
Munitions List from the ITAR (International Traffic in Arms
Regulations). This list gives the specific categories of
restricted exports and includes cryptographic exports. Traffic
entirely external to, entirely internal to, or into the USA is
not restricted.
To obtain a copy of the program, email to EMAIL_ADDRESS_OMITTED
with a subject “IOCCC request”. If you know that your ‘From’
line is incorrect, add a single line
“replyto you@your.correct.address” to the body of the message.
A deamon will autoreply.
WARNING: You must not re-export this out of the USA, or else
the men in black might get you.

Today, the nathan.c source code is the source code is what you would have received had you successfully completed the above instructions.

Today, the above instructions are no longer necessary. There have been reproduced above to provide historical context. Even so, the Alternate code allows you to see what the originally published code did.

Personal note from chongo:

I think the situation showed just how ridiculous US crypto regulations really were/are. Certain US federal officials can get away with shipping arms to certain nations in apparent violation of US laws, but I personally can’t re-distribute a program contest entry to the network!

Updated personal note from chongo:

We removed the email address from the above quote (although you can still see it in the nathan.orig.c and nathan.alt.c code) because sending email to that address is not required today and it is unknown if it is still valid. The nathan.c file now contains the source you would have received in reply.

Thankfully much of the ridiculous US crypto regulations has been amended to the extent where the above historical “workaround” is no longer required.

Author’s remarks:

Program use

This program is a hello world text encryptor/decryptor. 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.)

Portability (A little knowledge is a dangerous thing)

It’s written in ANSI C, and doesn’t even assume an ASCII character set, (it has an array of the characters to convert), so should be portable across many platforms. It passes gcc -ansi -pedantic -O -Wall with no warnings (You may get assignment in conditional warnings on other platforms though). Because I’ve heard that conditional jumps slow down fast processors, I’ve eliminated all the ifs from the code; indeed, as its only one statement, it should compile to one instruction and a suitably designed CISC machine. To speed compilation, there is only one statement in the loop, so that another scoping level does not need to be opened.

Being an encryptor/decryptor, you probably want the source code to be obfuscated, to hide the algorithm.

Obfuscation

In spite of the fact that it looks like a nice friendly hello world program, it isn’t (as documented above). (Short lines have been padded, as you’ll find if you look at an encrypted copy of the source.)

I’ve also named some of the macros from commonly used functions, just to keep things muddy. Of course, all the variables are misnamed. The program is kept simply (one for statement), by serious overuse of , and ?:. These are really confusing when used together, nested or put in argument lists (is that a comma operator, or argument separator?).

Primary files

• nathan.c - entry source code
• Makefile - entry Makefile
• nathan.alt.c - alternate source code
• nathan.orig.c - original source code
• try.sh - script to try entry

Secondary files

• 1992_nathan.tar.bz2 - download entry tarball
• README.md - markdown source for this web page
• .entry.json - entry summary and manifest in JSON
• .gitignore - list of files that should not be committed under git
• .path - directory path from top level directory
• index.html - this web page

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