201209120230 zr6ou

explained decrypted filler

seed 0

Metadata

Post ID: zr6ou
Title: 201209120230 → 2012-09-12 02:30 on A858's clock
Posted (UTC): 2012-09-12 06:30:06
Timezone: UTC−4 · title 02:30 against posted 06:30 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,168 hex characters · 584 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201209120230) = d8cf2a93b1e20af9349db7f96e45da42 (name+title)
GUIDs: 18
Filler GUID seed: new Random(0).Next(9) ✓ verified
Run: Run 31 (seed 15,917,281) (seed)
Draw: 24 · predicted N = 18 ✓
Machine boot: 2012-09-07 23:34–00:34 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 14 · 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: 1,168 hex characters = 584 bytes = 73 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209120230 (name+title). Key = MD5(password) = d8cf2a93b1e20af9349db7f96e45da42, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 18 GUIDs as hex (shown below).

Decrypted: GUID list

  1 8b5f8021-76a1-6256-9c8b-60f3d916a901
  2 0dd49eed-e3cb-77c8-90a1-553b0a8bc364
  3 9ede47b7-81d8-6254-b80e-2cb400e03cfc
  4 fba1d91f-8e6b-55e7-afa8-c903e4432b5a
  5 ff96e22a-fcc7-1951-86ae-dcd556d06724
  6 207fbe39-b6f9-5ca9-89c8-bc59b39cdf35
  7 091eca19-30dc-8fcd-8bf6-0f3215dd8d59
  8 30d0afd8-3bc7-39ff-8504-2ba18825c95e
  9 5b84ed68-9781-8d0d-aec7-78e0b85a7895
 10 17b9b22c-c3dd-2179-b564-e3a2c43bf378
 11 f92ba019-06ea-2fc3-a273-73216a0ca41b
 12 6812acbb-b12f-4f88-aa2b-f577373cf050
 13 adeca1df-9f1c-5dbf-859b-589efe850cdd
 14 3596940f-efa6-4707-8b9b-abf273eb0ab1
 15 06914586-4b9d-84e8-b4f2-f250026de188
 16 972623c4-c5e1-0fcd-86c3-49d9b119f522
 17 af908311-7913-746e-b88e-899eeca9b7c5
 18 75030dad-fa2f-8df9-a6b4-7ea008bfb2f9

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 676515838224548078. Exactly this sequence comes out of new Random(0).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 24 of Run 31 (seed 15,917,281): new Random(15917281), Next(8,64) per post. The RNG predicts N = 18; the post has N = 18 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-07 23:34–00:34).
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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