Home Hackvent 2020 Day 13: Twelve steps of christmas
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Day 13: Twelve steps of christmas

Description

On the ninth day of Christmas my true love sent to me…

nineties style xls,
eighties style compression,
seventies style crypto,
and the rest has been said previously.

dec13.xls

Hints

  • Wait, Bread is on the Nice list? Better check that comment again…

Solution

The comment reads

Not a loaf of bread which is mildly disappointing 1f 9d 8c 42 9a 38 41 24 01 80 41 83 8a 0e f2 39 78 42 80 c1 86 06 03 00 00 01 60 c0 41 62 87 0a 1e dc c8 71 23 Why was the loaf of bread upset? His plan were always going a rye. How does bread win over friends? “You can crust me.” Why does bread hate hot weather? It just feels too toasty.

Putting those bytes in a file:

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$ cat out.bin | od -tx2 -a
0000000    9d1f    428c    389a    2441    8001    8341    0e8a    39f2
         us  gs  ff   B sub   8   A   $ soh nul   A etx  nl  so   r   9
0000020    4278    c180    0686    0003    0100    c060    6241    0a87
          x   B nul   A ack ack etx nul nul soh   `   @   A   b bel  nl
0000040    dc1e    71c8    0023
         rs   \   H   q   #
0000045
$ file out.bin
out.bin: compress'd data 12 bits
$ cat out.bin| gzip -d | od -tx2 -a
0000000    4d42    884e    0012    0000    0000    008a    0000    007c
          B   M   N  bs dc2 nul nul nul nul nul  nl nul nul nul   | nul
0000020    0000    0227    0000    0227    0000    0001    0020    0003
        nul nul   ' stx nul nul   ' stx nul nul soh nul  sp nul etx nul
0000040    0000    87c4    0012    0000    0000    0000    0000    0000
        nul nul   D bel dc2 nul nul nul nul nul nul nul nul nul nul nul
0000060    0000    0000    0000
        nul nul nul nul nul nul
0000066

Flag

HV20{}