201209062230 zgy2o

explained decrypted filler

seed 968

Metadata

Post ID: zgy2o
Title: 201209062230 → 2012-09-06 22:30 on A858's clock
Posted (UTC): 2012-09-06 21:30:05
Timezone: UTC+1 · title 22:30 against posted 21:30 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,296 hex characters · 648 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201209062230) = e102fa837a4f92cc1caa57990eed2d1b (name+title)
GUIDs: 20
Filler GUID seed: new Random(968).Next(9) ✓ verified
Run: Run 30 (seed 1,932,335,625) (seed)
Draw: 2 · predicted N = 20 ✓
Machine boot: 2012-08-15 09:44–10:44 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 7 · 1
Tags: automated (decryptable)2012Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,296 hex characters = 648 bytes = 81 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209062230 (name+title). Key = MD5(password) = e102fa837a4f92cc1caa57990eed2d1b, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 20 GUIDs as hex (shown below).

Decrypted: GUID list

  1 d749c1fd-d9f5-3261-91b3-f6a1081fcd36
  2 6d3108ee-3f68-7840-ab0e-4c24bdf4a64a
  3 f2352b0a-b517-33cc-a1a4-2a20bc5003d9
  4 cc494fcc-6a94-1c57-a176-cb32738cc225
  5 e104f264-fc4b-203f-bc16-4532a4548577
  6 a8faf349-39e3-49d3-93f5-1169883cd8df
  7 311f54f0-84b9-5a70-9719-c7e3fbc982c2
  8 4759c822-0f80-0dd1-a4b1-efa31ea6ecc4
  9 54cc63ff-368b-674a-a795-87989587cfb4
 10 a4451663-69c5-2fde-88dc-80b2cf1cdebb
 11 2a622e88-5e97-4928-9027-e803095559f3
 12 6742ac82-b3b0-15d3-a4db-9d3d7ef81818
 13 002ab902-e1b8-0fcd-ae76-1c9a95031c82
 14 7d715288-37eb-0236-8448-e8f769ce15e3
 15 4012768f-9546-45a6-a2cc-78b851e0575b
 16 0f560626-70fe-5dca-a07e-0ad376418ea1
 17 f4649aa6-d7d8-6d87-b4a4-a0c38d44dbeb
 18 c2011278-6b39-1bfc-857e-93dff568d32c
 19 211e970a-ba30-77f1-a603-da74e604d024
 20 a0a04e53-6e8a-1193-8f24-f6b6b9d0ff62

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 37312450624100456171. Exactly this sequence comes out of new Random(968).Next(9): the per-post millisecond seed of the mask generator. The other 30 hex digits of each GUID are Guid.NewGuid() output and carry no message.
Explain the count. This post is draw 2 of Run 30 (seed 1,932,335,625): new Random(1932335625), Next(8,64) per post. The RNG predicts N = 20; the post has N = 20 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-08-15 09:44–10:44).
Conclusion. Filler. The content is fully explained by the two RNGs.

Metadata

From the post to its content

As posted (encrypted)

Decrypted: GUID list

Explanation

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