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Kurt, our crusty old mainframe admin, finally retired last week and I've been given the task of sorting through his files. Most of the files were comprehensible, if not understandable, like his old ~/.signature files with gems like "Everything I needed to know I learned in VAX/VMS." and "Solaris is for admins who can't handle UNIX." But one of his files just looked weird. Can anybody out there help me figure out what Kurt was trying to say?

One code to rule them all!

----------------------------------
|03|0D|10|13|06|16|26|AB|20|AB|24|
|FB|D8|09|B6|67|B7|AA|71|BF|9B|F5|
----------------------------------
|2D|21|24|05|24|0E|24|12|2D|0B|01|
|56|6C|60|35|75|9B|8C|E8|49|AA|90|
----------------------------------
|13|07|01|05|03|21|07|07|0E|2D|24|
|E7|CC|90|37|DC|24|91|17|A3|D0|88|
----------------------------------
|2D|11|1F|AB|1F|07|24|AA|24|27|2D|
|3C|AB|31|F0|30|8E|74|62|F6|D9|54|
----------------------------------
|24|06|16|AB|0C|24|A9|04|16|24|15|
|FB|65|AB|72|BD|60|E0|48|CA|89|87|
----------------------------------
|13|0B|A9|20|24|0C|04|AB|24|15|05|
|C6|9F|F6|B2|64|BD|48|F7|8D|C5|45|
----------------------------------
|30|0E|FE|1E|0C|00|13|12|A9|AB|0E|
|A4|82|81|01|79|D7|F0|28|DE|72|C0|
----------------------------------
|07|00|2E|24|04|16|05|AB|1D|05|24|
|D5|D7|02|F5|CB|B1|7D|DC|11|E9|75|
----------------------------------
|17|24|16|1F|07|0A|24|2C|24|13|AB|
|93|F6|D5|E5|F6|A1|8A|B1|61|A5|D0|
----------------------------------
|24|1A|A8|15|0C|1C|03|A8|A7|09|24|
|F5|13|58|B4|EC|6C|86|39|5C|F8|60|
----------------------------------
|20|2E|24|1C|0A|24|1D|24|1C|13|31|
|B3|84|61|50|6B|88|1F|74|56|E3|0B|
----------------------------------


-------------------------------
|8F|9F|8E|9E|  |47|  |44|8C|83|
-------------------------------
|53|B4|82|9B|  |  |98|  |9B|5E|
-------------------------------
|7A|  |79|9B|9B|9C|AA|B7|9E|  |
-------------------------------
|99|9A|  |8F|9E|8D|9D|8F|80|98|
-------------------------------
|B5|83|5F|51|9B|98|9A|  |5D|9C|
-------------------------------
|B7|9E|9D|A9|99|B5|B7|A8|B4|9E|
-------------------------------

Hint #1

The title is significant and can help get you started on interpreting the first matrix.

Hint #2

@aschelper's answer (as of 6/3/2020) is correct as far as it goes. But don't discard the hexadecimal yet! And two more words of advice for you: "Unicode blocks".

Hint #3

Focus on the characters in the Enclosed Alphanumerics block first. What does the grid look like if everything else is removed?

Hint #4

NURIKABE

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  • $\begingroup$ Just checking... are the numbers rot13(va urknqrpvzny)? $\endgroup$ – bobble Jun 1 at 18:55
  • $\begingroup$ @bobble: Yes, it is a safe assumption that, other than the header text and punctuation, the characters that appear in the file are hexadecimal digits. $\endgroup$ – Jeremy Dover Jun 1 at 19:55
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@aschepler and I have passed this one back and forth between us and I can now see the final answer! The final message left by Kurt is:

ASCII RULES

To build on @aschepler's initial realisation that each block of four characters in the first step:

is a representation of an "undisplayable Unicode code point"...

...we can then (thanks to prompting in hints by the OP):

Convert the blocks into their characters and focus on the ones which resemble numbers enclosed in circles or followed by a dot. If we highlight these in the grid:
enter image description here

...and then remove all the other characters:
enter image description here

...we see something resembling the starting grid of a 'Nurikabe' grid deduction puzzle.

This resolves as follows:

enter image description here

We can then overlay this solution onto the original grid, so that only certain Unicode symbols are readable in the whitespace:
enter image description here

This yields the symbols:
enter image description here

The next step is to convert this into another instruction based on which basic alphanumeric characters these symbols most closely resemble. This appears to yield:

XOR BY DF SHIFT RIGHT 2x BLOCK 2540

At this point @aschepler picked up the baton again and realised that this instruction could be applied to the bottom grid to generate:

A further grid of Unicode symbols where the code point number lies in the "Box drawing" block:

enter image description here

(Explanation: (for those who - like me - know little or nothing of binary mathematics) This instruction describes a sequence of binary operations that need to be carried out on the 2-digit hexadecimal numbers in the second diagram of the puzzle:

- XOR BY DF: Convert the original hexadecimal number to binary and compare each 0/1 bit with its counterpart in the binary representation of the hex number DF, i.e. 11011111. The output has a '0' in every bit position where the two compared numbers matched and a '1' wherever they differed.

- SHIFT RIGHT 2x: A 'right shift' operation involves moving each bit in the output a certain number of places to the right - in this case, 2 places. The original bits in the rightmost 2 positions 'fall off the end' and disappear from consideration.

- BLOCK 2540: Starting at the Unicode character 'U+2540', add on the result from the previous operation to reach the target number.

Example: The first character in the second grid is '8F':
XOR BY DF: XOR 8F (10001111) by DF (11011111) to get 01010000.
SHIFT RIGHT 2x: 01010000 becomes 00010100. This is the decimal number 20.
BLOCK 2540: Count on 20 positions from U+2540 to reach U+2554 (remembering Unicode uses hexadecimal digits here). This is the symbol '╔'.)

I then noticed that there is one final step to apply:

By shifting these rows right by a certain amount (and wrapping around to the start of line when symbols are pushed past the end) the symbols can be aligned to form a readable message:

enter image description here
If Kurt is the type of programmer who's into VAX/VMS, then perhaps it's no surprise he also thinks that ASCII RULES!

| improve this answer | |
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  • $\begingroup$ Great progress @Stiv! I realize now that I should have coded Hint 4 into the matrix somehow. You're almost there...suggest looking back at all of the data in the file to see if it stimulates any thoughts. $\endgroup$ – Jeremy Dover Jun 5 at 15:22
  • $\begingroup$ I think I have a Part 3, but I'm not sure what's next again. $\endgroup$ – aschepler Jun 5 at 23:54
  • 1
    $\begingroup$ That's it! You guys got it right in every particular. To all who like the solution, please make sure to upvote both this answer and @aschelper's, since both have about half of the critical steps for solution. $\endgroup$ – Jeremy Dover Jun 6 at 17:10
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Pieceing through this.

Part 1:

The "one code" in the title suggests Unicode, and undisplayable Unicode code points are often rendered as a box containing four hexadecimal digits, similar to the boxes in the first grid. Treating the first 11x11 grid as Unicode code points turns up a lot of digit characters, variations on digits, and glyphs which look visually like Arabic digits or like Latin letters.

The characters raw (how many you correctly see may depend on your browser's support):

ϻ ෘ ဉ Ꮆ ٧ ᚷ ⚪ ꭱ ₿ ꮛ ⓵ 
ⵖ Ⅼ ① Ե ⑵ ປ ⒌ የ ⵉ ப Ɛ 
Ꮷ ߌ Ɛ Է Ϝ ℤ ޑ ܗ ຣ ⷐ ⒈ 
ⴼ ᆫ ἱ ꯰ ἰ ގ ⑴ ꩢ ⓶ ⟙ ⵔ 
⓻ ٥ ᚫ ꭲ ಽ ① ꧠ ш ᛊ ⒉ ᖇ 
Ꮖ ட ꧶ ₲ ⑤ ಽ ш ꯷ ⒍ ᗅ Յ 
イ ຂ ﺁ ḁ ౹ × Ᏸ ረ ꧞ ꭲ ເ 
ߕ × ⸂ ⓵ Ӌ ᚱ ս ꯜ ᴑ ש ⑵ 
ន ⓶ ᛕ ῥ ߶ ડ ⒊ ⲱ ② Ꭵ ꯐ 
⓵ ᨓ ꡘ ᖴ ೬ ᱬ Ά ꠹ Ꝝ ৸ ① 
₳ ⺄ ② ᱐ ੫ ⒈ ᴟ ⑴ ᱖ Ꮳ ㄋ 

The code point values and official names:

U+03fb GREEK SMALL LETTER SAN
U+0dd8 SINHALA VOWEL SIGN GAETTA-PILLA
U+1009 MYANMAR LETTER NYA
U+13b6 CHEROKEE LETTER LO
U+0667 ARABIC-INDIC DIGIT SEVEN
U+16b7 RUNIC LETTER GEBO GYFU G
U+26aa MEDIUM WHITE CIRCLE
U+ab71 CHEROKEE SMALL LETTER E
U+20bf BITCOIN SIGN
U+ab9b CHEROKEE SMALL LETTER QUV
U+24f5 DOUBLE CIRCLED DIGIT ONE

U+2d56 TIFINAGH LETTER YAGH
U+216c ROMAN NUMERAL FIFTY
U+2460 CIRCLED DIGIT ONE
U+0535 ARMENIAN CAPITAL LETTER ECH
U+2475 PARENTHESIZED DIGIT TWO
U+0e9b LAO LETTER PO
U+248c DIGIT FIVE FULL STOP
U+12e8 ETHIOPIC SYLLABLE YA
U+2d49 TIFINAGH LETTER YI
U+0baa TAMIL LETTER PA
U+0190 LATIN CAPITAL LETTER OPEN E

U+13e7 CHEROKEE LETTER TSU
U+07cc NKO LETTER I
U+0190 LATIN CAPITAL LETTER OPEN E
U+0537 ARMENIAN CAPITAL LETTER EH
U+03dc GREEK LETTER DIGAMMA
U+2124 DOUBLE-STRUCK CAPITAL Z
U+0791 THAANA LETTER DAVIYANI
U+0717 SYRIAC LETTER HE
U+0ea3 LAO LETTER RO
U+2dd0 ETHIOPIC SYLLABLE XYA
U+2488 DIGIT ONE FULL STOP

U+2d3c TIFINAGH LETTER YAF
U+11ab HANGUL JONGSEONG NIEUN
U+1f31 GREEK SMALL LETTER IOTA WITH DASIA
U+abf0 MEETEI MAYEK DIGIT ZERO
U+1f30 GREEK SMALL LETTER IOTA WITH PSILI
U+078e THAANA LETTER GAAFU
U+2474 PARENTHESIZED DIGIT ONE
U+aa62 MYANMAR LETTER KHAMTI CHA
U+24f6 DOUBLE CIRCLED DIGIT TWO
U+27d9 LARGE DOWN TACK
U+2d54 TIFINAGH LETTER YAR

U+24fb DOUBLE CIRCLED DIGIT SEVEN
U+0665 ARABIC-INDIC DIGIT FIVE
U+16ab RUNIC LETTER AESC
U+ab72 CHEROKEE SMALL LETTER I
U+0cbd KANNADA SIGN AVAGRAHA
U+2460 CIRCLED DIGIT ONE
U+a9e0 MYANMAR LETTER SHAN GHA
U+0448 CYRILLIC SMALL LETTER SHA
U+16ca RUNIC LETTER SOWILO S
U+2489 DIGIT TWO FULL STOP
U+1587 CANADIAN SYLLABICS TLHI

U+13c6 CHEROKEE LETTER QUA
U+0b9f TAMIL LETTER TTA
U+a9f6 MYANMAR TAI LAING DIGIT SIX
U+20b2 GUARANI SIGN
U+2464 CIRCLED DIGIT FIVE
U+0cbd KANNADA SIGN AVAGRAHA
U+0448 CYRILLIC SMALL LETTER SHA
U+abf7 MEETEI MAYEK DIGIT SEVEN
U+248d DIGIT SIX FULL STOP
U+15c5 CANADIAN SYLLABICS CARRIER GHO
U+0545 ARMENIAN CAPITAL LETTER YI

U+30a4 KATAKANA LETTER I
U+0e82 LAO LETTER KHO SUNG
U+fe81 ARABIC LETTER ALEF WITH MADDA ABOVE ISOLATED FORM
U+1e01 LATIN SMALL LETTER A WITH RING BELOW
U+0c79 TELUGU FRACTION DIGIT ONE FOR ODD POWERS OF FOUR
U+00d7 MULTIPLICATION SIGN
U+13f0 CHEROKEE LETTER YE
U+1228 ETHIOPIC SYLLABLE RA
U+a9de JAVANESE PADA TIRTA TUMETES
U+ab72 CHEROKEE SMALL LETTER I
U+0ec0 LAO VOWEL SIGN E

U+07d5 NKO LETTER TA
U+00d7 MULTIPLICATION SIGN
U+2e02 LEFT SUBSTITUTION BRACKET
U+24f5 DOUBLE CIRCLED DIGIT ONE
U+04cb CYRILLIC CAPITAL LETTER KHAKASSIAN CHE
U+16b1 RUNIC LETTER RAIDO RAD REID R
U+057d ARMENIAN SMALL LETTER SEH
U+abdc MEETEI MAYEK LETTER LAI LONSUM
U+1d11 LATIN SMALL LETTER SIDEWAYS O
U+05e9 HEBREW LETTER SHIN
U+2475 PARENTHESIZED DIGIT TWO

U+1793 KHMER LETTER NO
U+24f6 DOUBLE CIRCLED DIGIT TWO
U+16d5 RUNIC LETTER OPEN-P
U+1fe5 GREEK SMALL LETTER RHO WITH DASIA
U+07f6 NKO SYMBOL OO DENNEN
U+0aa1 GUJARATI LETTER DDA
U+248a DIGIT THREE FULL STOP
U+2cb1 COPTIC SMALL LETTER OOU
U+2461 CIRCLED DIGIT TWO
U+13a5 CHEROKEE LETTER V
U+abd0 MEETEI MAYEK LETTER PHAM

U+24f5 DOUBLE CIRCLED DIGIT ONE
U+1a13 BUGINESE LETTER VA
U+a858 PHAGS-PA LETTER RA
U+15b4 CANADIAN SYLLABICS BLACKFOOT WE
U+0cec KANNADA DIGIT SIX
U+1c6c OL CHIKI LETTER UNN
U+0386 GREEK CAPITAL LETTER ALPHA WITH TONOS
U+a839 NORTH INDIC QUANTITY MARK
U+a75c LATIN CAPITAL LETTER RUM ROTUNDA
U+09f8 BENGALI CURRENCY NUMERATOR ONE LESS THAN THE DENOMINATOR
U+2460 CIRCLED DIGIT ONE

U+20b3 AUSTRAL SIGN
U+2e84 CJK RADICAL SECOND THREE
U+2461 CIRCLED DIGIT TWO
U+1c50 OL CHIKI DIGIT ZERO
U+0a6b GURMUKHI DIGIT FIVE
U+2488 DIGIT ONE FULL STOP
U+1d1f LATIN SMALL LETTER SIDEWAYS TURNED M
U+2474 PARENTHESIZED DIGIT ONE
U+1c56 OL CHIKI DIGIT SIX
U+13e3 CHEROKEE LETTER TSA
U+310b BOPOMOFO LETTER N

Part 2: See Stiv's answer for how the characters in this grid from the Unicode "Enclosed alphanumerics" block U+2460 - U+24FF leads to a Nurikabe puzzle and highlights the characters

ᚷ ⚪ ꭱ ₿ ⵖ Ꮷ Ϝ ຣ ⴼ ἱ ᚫ ꭲ ᖇ Ꮖ ₲ ꯷ イ ຂ × Ᏸ ረ ꧞ ເ ᛕ ߶ ડ Ꝝ ᱐

Part 3:

Now moving to the second grid. The instructions from the first grid look like "XOR by DF, Shift Right 2x, Block 2540". Taking each hexadecimal byte B in the second grid and applying the formula ((B ^ 0xDF) >> 2) + 0x2540 gives a Unicode code point number in the "Box drawing" block.

These characters are:

╔═╔═ ╦ ╦╔╗
╣╚╗║  ║ ║╠
╩ ╩║║═╝╚═ 
║║ ╔═╔═╔╗║
╚╗╠╣║║║ ╠═
╚══╝║╚╚╝╚═

Or, with more space between them:

 ╔ ═ ╔ ═   ╦   ╦ ╔ ╗ 

 ╣ ╚ ╗ ║     ║   ║ ╠ 

 ╩   ╩ ║ ║ ═ ╝ ╚ ═   

 ║ ║   ╔ ═ ╔ ═ ╔ ╗ ║ 

 ╚ ╗ ╠ ╣ ║ ║ ║   ╠ ═ 

 ╚ ═ ═ ╝ ║ ╚ ╚ ╝ ╚ ═ 

This looks to me like a puzzle of Net/FreeNet/NetWalk, with some parts (the graph leaves?) missing. But in the rules of that puzzle, the region near the center bottom containing

═ ╔ ═

║ ║ ║

can have no solution...

| improve this answer | |
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  • 2
    $\begingroup$ aschepler and @Stiv Great teamwork! You are almost there...as you have discovered, this is not a Net puzzle (though that would have been a much better idea than what I did). I suggest looking at the first (less space) version of the box drawing to get an idea how the pieces fit together. May the Force be with you! $\endgroup$ – Jeremy Dover Jun 6 at 0:03
  • $\begingroup$ Nice work @aschepler. Thanks to your further observations I think I finally found the overall answer. Nice working with you :) +1 $\endgroup$ – Stiv Jun 6 at 16:37
  • 1
    $\begingroup$ I love everything about how you guys solved this puzzle! I gave @Stiv the checkmark because his had the final answer, but really you both deserve equal (and full!) credit. $\endgroup$ – Jeremy Dover Jun 6 at 17:13
  • $\begingroup$ Yay! Not like I needed the imaginary Internet points. $\endgroup$ – aschepler Jun 6 at 17:51

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