201108161340 jkscb
explained unencrypted manual
A hex grid of 9 masked GUIDs, seed 880. Hex-ASCII. Its MD5 is the key of jkuyr.
From the post to its content
As posted
6437366664323662 6366203161343261 6161323366203661 6530393233373634 2035370D0A356239 6332352032313263 3965303863332038 3166353066656136 3920343133366331 0D0A643320373537 6165393834373020 3762373861636436 3630206561613365 6463663634200D0A 3062346131356530 2035396137333265 3838372062646630 6265343034662031 3738320D0A366130 3520326532663866 6666343320393661 3762653834376220 6365393666313333 0D0A203263616636 3131643361203833 3531303361643862 2036643965306166 3034662062630D0A 3235393764322064 6236623161313739 3120393261646561 6563383720636337 6539350D0A653820 6537336130613734 3630203833383039 6435376331206462 3564653031626336 200D0A3566366439 3232302035333739 3733343662382038 3934316437656230 3720656266610D0A 20
- Decode. Each pair of hex characters is one byte; decoding them gives the text below.
Decoded from hex
d76fd26bcf 1a42aaa23f 6ae0923764 57 5b9c25 212c9e08c3 81f50fea69 4136c1 d3 757ae98470 7b78acd660 eaa3edcf64 0b4a15e0 59a732e887 bdf0be404f 1782 6a05 2e2f8fff43 96a7be847b ce96f133 2caf611d3a 835103ad8b 6d9e0af04f bc 2597d2 db6b1a1791 92adeaec87 cc7e95 e8 e73a0a7460 83809d57c1 db5de01bc6 5f6d9220 53797346b8 8941d7eb07 ebfa
- Mask digits. Each GUID's 13th hex character, its version digit (highlighted), is a mask digit. Read in order, the mask digits are the output of the seeded generator.
GUID list
1 d76fd26b-cf1a-42aa-a23f-6ae092376457 2 5b9c2521-2c9e-08c3-81f5-0fea694136c1 3 d3757ae9-8470-7b78-acd6-60eaa3edcf64 4 0b4a15e0-59a7-32e8-87bd-f0be404f1782 5 6a052e2f-8fff-4396-a7be-847bce96f133 6 2caf611d-3a83-5103-ad8b-6d9e0af04fbc 7 2597d2db-6b1a-1791-92ad-eaec87cc7e95 8 e8e73a0a-7460-8380-9d57-c1db5de01bc6 9 5f6d9220-5379-7346-b889-41d7eb07ebfa
Explanation
- Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives
407345187. Exactly this sequence comes out ofnew Random(880).Next(9): the per-post millisecond seed of the mask generator. The other 30 hex digits of each GUID areGuid.NewGuid()output and carry no message. - Explain the count. Grouped in Before the scheduler: before the scheduled app (Jun 26 2012): sparse single tool runs / hand lists (o5o4o, jbucr, jkuyr), 2011 genuine-v4 lists; no long-lived count stream to fit
201108161340 — grid and MD5
Status: verified against the archived post.
Transformation:
- Remove whitespace and hex-decode the Reddit body.
- Read the result as a grid of hexadecimal-looking strings.
- Remove every space and line break, including the trailing one: what is left is the nine GUIDs as one lower-case string of 288 characters.
- MD5 that string.
The resulting digest is:
bbb21a107025d1debbd16a38cf94bf5f
Only this form gives it. Keeping the line breaks, keeping the final newline, or upper-casing the string gives a different
digest. The digest is the sidebar value that appeared with the next post, jkuyr, and used directly as a
3DES key it decrypts that post. The grid itself is filler, nine masked GUIDs from new Random(880). The puzzle was the
chain of steps, which the August 2011 GIF posts lead up to: see
the GIF posts page.
Solution summary
- Method
- hex-ASCII grid, no cipher
- Result
- 9 masked GUIDs, seed 880
- Explanation
- Grid rows are the masked GUIDs (Random(880).Next(9)); the grid's MD5 is the sidebar value and jkuyr's key
- Re-checked
- hex -> grid -> MD5