Shortwave and numbers stations

[sandm000]

If things get really bad around here (inside the US) I was wondering if you could set up a network of shsortwavers to spread around messages, either openly or encoded.

[aries]

They do it in China to spread the gospel.

I've added a shortwave transmitter/reciever to my list of things to aquire one day.

[Dave Ridley]

they say ham operators do well in crises, but it is considered bad form to charge for the service... i think that's counterproductive to take profit out of it but that is the culture.

[KBCraig]

they say ham operators do well in crises, but it is considered bad form to charge for the service... i think that's counterproductive to take profit out of it but that is the culture.

You've probably heard redneck jokes about getting stuck in the snow or mud, and being rescued by three guys crammed into a 4WD pickup with a case of beer. As it's told, "Don't try to pay them. They live for this!"

The same is true of hams. They live for the opportunity to do something more than CQs and contact logs. Let them have their fun. It's all the payment they require.

Kevin

[sandm000]

I've been developing an alternative coding system (the current system is 2 digits then 3 digits) and it isn't quite clear if this is 1 letter or not.

A one time sheet with > 50,000 codes available for each message that can be presented to each person without any need to contact "home base" or "HQ", something that may appear in newspapers or magazines, similar to A Beautiful Mind.

I'm talking of course of SUDOKU.

Long ignorable message to follow.

[sandm000]

1)Finish a puzzle
2)write out a message
3)convert to ascii
4)break into 3 digit blocks
5)turn puzzle into one time pad
6)perform a mathematical operation
7)broadcast the message
8)receive message
9)disassemble message
10)convert back from ascii
STEP ONE:
Finish THE SUDOKU IN a PREVIOUSLY AGREED UPON Newspaper.
(EG 3/8/06 GUARDIAN SUDOKU CLASSIC
  123 456 789
  --- --- ---
A|962 837 415
B|834 651 729
C|517 924 368

D|628 513 974
E|495 276 831
F|173 498 256

G|286 745 193
H|751 389 642
I|349 162 587)

STEP TWO:
WRITE OUT THE MESSAGE TO BE SENT
(EG: This is Brian's first attempt at a crypto algorithm.)
(include jargon, 1337, 926312-6003, mYsteRioUs caPITiliZAtion, random punctuation @#8^O*~)

Step three:
convert message to ascii code (using entire message above, including parentheses)
40 69 71 58 32 84 104 105 115 32 105 115 32 66 114 105 97 110 39 115 32 102 105 114 115 116 32 97 116 116 101 109 112 116 32 97 116 32 97 32 99 114 121 112 116 111 32 97 108 103 111 114 105 116 104 109 46 41
40 105 110 99 108 117 100 101 32 106 97 114 103 111 110 44 32 49 51 51 55 44 32 57 50 54 51 49 50 45 54 48 48 51 44 32 109 89 115 116 101 82 105 111 85 115 32 99 97 80 73 84 105 108 105 90 65 116 105 111 110 44 32 114 97 110 100 111 109 32 112 117 110 99 116 117 97 116 105 111 110 32 64 35 56 94 48 42 126 41
(148 characters, you can go to encoding now or do the following)

Step four (optional):
Regroup to 3# blocks
406 971 583 284 104 105 115 321 051 153 266 114 105 971 103 911 532 102 105 114 115 116 329 711 611 610 110 911 211 632 971 163 297 329 911 412 111 211 611 132 971 081 031 111 141 051 161 041 094 641 401 051 109 910
811 710 010 132 106 971 141 031 111 104 432 495 151 554 432 575 054 514 950 455 448 485 144 321 098 911 511 610 182 105 111 851 153 299 978 073 841 051 081 059 065 116 105 111 110 443 211 497 110 100 111 109 321 121 171 109 911 611 797 116 105 111 110 326 435 569 448 421 264 1<-fill in last digit(s) with zeroes (now 124 'characters')

Step five:
Break your sudoku puzzle into 3# blocks
(ie see puzzle above -> 962 628 283 837 374 741 415 158 583 834... when you reach the bottom wrap around again to the top so the last three blocks of the example puzzle above would be 587 879 796.) This gives us the first 81 3# blocks. You can rotate the paper 90' CCW (or CW if you and your decoder agree) and start again, and 90' more, and 90' more. Total: 324 3# blocks.  If more 3# blocks are needed there are multiple ways to retrieve 3# blocks from the grid (e.g. diagonal-A1+B2+C3=937, knight-C4+D4+D3=431, diagonalinear E8+F7+E7=328, you can go step wise A1=9 .:A1+9=B1 B1=8 .:B1+8=B9 B9=9 .:A1+B1+B9=989, just so long as the encoder and decoder know the order that the 3# blocks are going to be in)

Step six:
Math it up funny man
character [operation] 3# block = result
Modulus-not good because the character (upon decode) will equal 3# block * n + result (where n is any whole number), however it is good to keep around just in case (maybe you only use it when 3# blocks are > 500)
Division - not good because you would lose the remainder
Multiplication - not good because each result should be 3 digits long, and with multiplying you will wind up with very long strings of numbers.
Addition - somewhat not good, again results should be 3 digits long, and occasionally you will wind up with a 4 digit number.
Subtraction - Negative numbers? how do we report those? Answer, we don't, just drop the negative sign. When you decode you will just wind up with a negative character so drop the negative again and you have the character.
Subtraction is your best bet and if you wind up with a 2 digit answer instead of a 3 digit answer insert a 0 at the beginning of the number.
(eg:
406-962=556
971-628=343
583-283=300
284-837=553
104-374=270
105-741=636
115-415=300
321-158=163
051-583=532)

Step seven:
Broadcast the message to the world.
556343300553270636300163532........

Step eight:
Receive message (write it down on some blank sudoku sheets)
___________
___|___|___|<-received message
___|___|___|<-3# blocks from sudoku in the paper (see step 5)
___|___|___|<- result of subtraction = original 'character'

Step Nine:
If any of the blocks are 3 digits and begin with 3-9 then you must dissassemble the blocks...
406971583284104105115321051153266114105971103911532102105114115116329711611610110911211632971163297329911412111211611132971081031111141051161041094641401051109910811710010132106971141031111104432495151554432575054514950455448485144321098911511610182105111851153299978073841051081059065116105111110443211497110100111109321121171109911611797116105111110326435569448421264100

Goes to:
40 69 71 58 32 84 104 105 115 32 105 115 32 66 114 105 97 110 39 115 32 102 105 114 115 116 32 97 116 116 101 109 112 116 32 97 116 32 97 32 99 114 121 112 116 111 32 97 108 103 111 114 105 116 104 109 46 41 40 105 110 99 108 117 100 101 32 106 97 114 103 111 110 44 32 49 51 51 55 44 32 57 50 54 51 49 50 45 54 48 48 51 44 32 109 89 115 116 101 82 105 111 85 115 32 99 97 80 73 84 105 108 105 90 65 116 105 111 110 44 32 114 97 110 100 111 109 32 112 117 110 99 116 117 97 116 105 111 110 32 64 35 56 94 48 42 126 41
because the values you will encouter will be from 30 - 256 you don't have to worry about 2 digit decisions.  If it begins with a 3-9 it will be 2 digits long, if it begins with a 1 or 2 it will be 3 digits long. (Example:406971583284104105115 begins with 4 .: must be 2 digits .: first character = 40.
           6971583284104105115 begins with 6 .: must be 2 digits .: second character = 69.
             71583284104105115 begins with 7 .: must be 2 digits .: third character = 71.
               583284104105115 begins with 7 .: must be 2 digits .: fourth character = 58.
                 3284104105115 begins with 3 .: must be 2 digits .: fifth character = 32.
                   84104105115 begins with 8 .: must be 2 digits .: sixth character = 84.
                     104105115 begins with 1 .: must be 3 digits .: seventh character = 104.
                        105115 begins with 1 .: must be 3 digits .: eighth character = 105.
                           115 begins with 1 .: must be 3 digits .: ninth character = 115.

Step Ten:
Convert from ASCII to Text
(e.g. 40 =( , 69=E, 71=G, 58=:, 32= , 84=T, 104=h, 105=i, 115=s.) etc. etc.

[sandm000]

There is obviously room for improvement, for instance one could use Unicode instead of Ascii encoding.
An interesting side note is that a sudoku puzzles only has numbers 1-9 so it as base nine system.

I wrote a program in basic (you should have a compiler if you have Excel) that can take in text and a puzzle and encode it in this way. send a message if you'd like to see it.

I have yet to write a program to decode the data.