201210041342 10y2o5

explained decrypted filler

3DES(name+title) ECB, 10 GUIDs, seed 428

Metadata

Post ID: 10y2o5
Title: 201210041342 → 2012-10-04 13:42 on A858's clock
Posted (UTC): 2012-10-04 17:42:22
Timezone: UTC−4 · title 13:42 against posted 17:42 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 656 hex characters · 328 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210041342) = b6636e35d6bc665ef149fec42601fb2b (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 10
Filler GUID seed: new Random(428).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 173 · predicted N = 10 ✓
Machine boot: 2012-09-22 10:16–10:36 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 0 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+titlerun: seed

From the post to its content

As posted (encrypted)

3E2BD5A5BDD482FA 48E7FD05EC76EFEA 7E67D34B35D58D45 54AEF0B06A2037BA 16140C388F7C57AA 15A5335241FD314A 25307695182B4391 7AA0A3FB988CAC4D F9A8EB0CBC5BF8DD 7985A8ED610922CB F27A5CC34171F827 C65F218BFA7645C8 D13321E29E918991 4FC88B22D5A39E78 51E12890A9BC13DE 6CC92CE38821E2EF 17440DD8BB96B4D3 C60199A92CD51A00 BDF2B275ECA27323 5014AD686AB6F61C A293DA19AC987AC6 6F61CDDEAE467473 0B13ACE8AA259790 3326A636FFCA0C9D F1C61A5B32BBDEB6 5EF1EB781D9F5FE8 6C1CE4DF1E44B39B 1B09BF6483E0E2DB 75269AC1439E6242 3A2F07461E0F95EC 2917AFE88439B58D 8A8BA9FD50571E0B CB39A9851F1DDDAC F28B513D5CFB2B02 C0F5FBF9EAC20B87 40C00094672877F4 803FF0F6FA9BE078 643BB1290542B84E 4AE2D2BC960B8B3E 779ADCE66E235E49 A8DF1886251CF49D

Read the ciphertext. Strip whitespace: 656 hex characters = 328 bytes = 41 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210041342 (name+title). Key = MD5(password) = b6636e35d6bc665ef149fec42601fb2b, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 10 GUIDs as hex (shown below).

Decrypted: GUID list

  1 14c06a7b-7a77-23f9-b7aa-291d15989a25
  2 e91d52f1-296d-3a09-bac5-25fe2800212d
  3 fbc23641-d379-832c-bca1-d755774a9e89
  4 a3531bd8-73e7-8d5b-907f-11849dfbff08
  5 5bf14847-f5a8-37d3-a861-bbede455f77b
  6 99e58b31-16e2-5fac-9857-12fa5d5b589c
  7 e5d43b25-3047-6212-a7ab-2f2b48e9a733
  8 6bda7ffa-2b66-12bc-b775-0d38c8089056
  9 308d32b9-3f32-8e46-b0ca-ce0acdc130c8
 10 203e1141-e6dc-0e05-808a-862d56c6394f

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 2388356180. Exactly this sequence comes out of new Random(428).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 173 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 10; the post has N = 10 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:16–10:36).
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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