Postcard Code

The Postcard Code

The code of 221545484848465100503215 is beneath the Semacode on the Perplex City Postcard, does this mean something? This page is going to be used as a workpad for the puzzle.

Images

Postcard Semacode

Theories

• We've tried using numerical translations into Kanji and Hebrew. No luck, though "2210" gives us "SEEK."
• Various ROTing, and conversion to ASCII then ROTing proved...nothing but gibberish.
• Equally, running modulus calculations on the number to bring it into number spaces for ASCII etc. AND converting to ASCII as base 10 and base 16 AND ROTing the results gives yet more gibberish.
• Ditto multiplying the number by 2210 (the number next to the semacode stamp on the card) and trying the above operations.
• Tried translating to EBCDIC: still gibberish.
• Too many digits to be an ISBN or a latitude/longitude.
• Tried mapping numbers to characters in the text of the postcard (i.e. first character in Sente's message is 00, second character is 01 etc.) trying various starting points and different combinations of including/ignoring spaces, hyphens, line-breaks etc. Results were meaningless so ROTed them but still no obvious message.
• Shish tried converting to music using 'beep' command in Linux and mobile phone ringtones but no obvious answers or recognisable tunes were found.
• Frequency analysis of the numbers was similarly unsuccessful. Assuming the string was one-digit numbers gave far too much repetition of characters (for example the 484848 would probably be tetete or etetet) for a meaningful message. Assuming the string was 2 (or more) digit numbers prevented frequency analysis simply because there wasn't enough data to work with (frequency analysis works best over a very large amount of encrpyted data).
• Currently trying various ways of converting number to binary (all possible methods of writing number in binary have been listed on unfiction forum by Seej) then converting that binary to morse code, i.e. 0 = dot, 1 = dash (or vice versa) and interpreting that series of dots and dashes (actually more complicated than it sounds as morse code characters don't always have the same number of dots and dashes so there's no clear way to tell when one character has ended and another has begun).
• Assuming code is a series of 2 digit numbers:

 - Reasons to believe this:
     1) "484848" jumps out as a pattern
     2) the numbers are clearly clustered and not very random
     3) all 12 numbers range from 00-51
 - Since numbers range 00-51 we've tried several simple translations using 2 alphabets 
   (ex. A=00, B=01,...Z=25,A=26,...Z=51).  
   - In some cases "484848" translates to "www", but the rest doesn't look like a URL (also tried 
     tinyurl)
   - In other cases, it translates into a set of letters which can be scrambled to come up with "cube"
     but the rest is undecipherable.  Note: letter on website refers to "XXX Cube" where XXX is blacked
     out.  It looks like about 6 or 7 letters in length, so it could be a proper name.

• It has been suggested that the number may simply be a key for a cipher such as MD5 or RSA but there is no way to verify this until further encrypted messages are received on which the number can be used as a key. This is unlikely to happen until the game starts properly.