So I was playing Doom3, an old favourite. And I came upon this screen:

The “encrypted” data is:

4697 BNDWQ ERGAZS GHQAZ 1029GG3 VBNY77
KDMH LGSLDG SDLGKSE SDTK YU90G 576457 DDKLFG 67
EO5IY DKFJ -386 FDGL 3465 FG34 36FDG FGL DFGJDF
DFKGJ 6 KDFG DFJ DFGDFJG DFGJLSD APQAZ 100Y
SDFM Z LM TIYOU KDMH LGSLDG SDLGKSE SDTK 576457
DDKLFG AVFTYU8P FKGKYR FJFGJH RETKJER DFKJA

It didn’t look random enough to me, meaning it was possibly encoded, so I started poking at it.

The first thing I tried was ROT13, but that wasn’t it.

I then tried mapping the alphabet to the reverse alphabet (my sister’s idea), but that wasn’t it either.

Then I ran this PHP program:

function main() {

  $text = file_get_contents( 'doom3-notes.txt' );

  freqhist( $text );

}

function freqhist( $text ) {

  $map = [];
  $len = strlen( $text );

  for ( $i = 0; $i < $len; $i++ ) {

    $char = $text[ $i ];

    if ( $char === "\n" || $char === ' ' ) { continue; }

    inc( $map, $char );

  }

  asort( $map );

  report( $map );

}

function inc( &$map, $char ) {

  if ( ! array_key_exists( $char, $map ) ) { $map[ $char ] = 0; }

  $map[ $char ]++;

}

function report( $map ) {

  echo "size: " . count( $map ) . "\n";

  foreach ( $map as $char => $count ) {

    echo "$char: $count\n";

  }
}

And the output was:

size: 35
-: 1
W: 1
2: 1
P: 2
1: 2
8: 2
B: 2
N: 2
I: 2
O: 2
V: 2
9: 3
Q: 3
U: 3
M: 4
0: 4
H: 4
Z: 4
R: 4
T: 5
4: 5
3: 5
A: 6
5: 6
E: 6
Y: 7
6: 8
7: 8
J: 10
S: 11
L: 12
K: 15
F: 21
G: 25
D: 27

And this report was enough for me to deduce what had happened. This was obviously the work of a busy designer entering “random” data from their QWERTY keyboard.

You can tell because all the frequently occurring letters D, G, F, K, L, etc. are all on the home row on a QWERTY keyboard. Someone sat there pressing “random” keys. It’s not an encoded message.

Puzzle solved. But a little disappointing.