201209231316 10cj9o

explained decrypted filler

3DES(name+title) ECB, 16 GUIDs, seed 196

Metadata

Post ID: 10cj9o
Title: 201209231316 → 2012-09-23 13:16 on A858's clock
Posted (UTC): 2012-09-23 17:16:18
Timezone: UTC−4 · title 13:16 against posted 17:16 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,040 hex characters · 520 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201209231316) = a1993dd458258794f6d6d1be8db8f584 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 16
Filler GUID seed: new Random(196).Next(9) ✓ verified
Run: Run 34 (seed 83,105,000) (seed)
Draw: 34 · predicted N = 16 ✓
Machine boot: 2012-09-22 10:23–10:24 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 1 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209231316 (name+title). Key = MD5(password) = a1993dd458258794f6d6d1be8db8f584, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 16 GUIDs as hex (shown below).

Decrypted: GUID list

  1 b1d5f4d3-7aa3-106e-baf7-6a70d9171de7
  2 d69c03e2-ffdb-219d-b28f-1bd5f084f7ee
  3 9d5a8c8a-be0e-6e88-9d1a-d4b55c728e19
  4 910d68fc-c5ff-3d9e-9d94-666f4187771f
  5 3ea3e2d3-5fd2-61b4-ae41-556a83ff7a5c
  6 a28b91fd-bf09-776a-bb25-467bd9ae9c87
  7 daee014d-5ea8-6561-9bff-f5ab97796626
  8 56b2a513-7f74-6adb-89fd-d1931b8d219a
  9 14329d42-c625-2b97-8b88-5e11cc28e01b
 10 974b8bcb-1cf6-49fe-925d-a8671a6026b0
 11 c2e7a163-2f7a-6ff8-bb8c-13fc6bafa9b3
 12 ddceb4db-4858-48b6-bc90-19e4e3a1d005
 13 1a2d7dae-62b6-3fba-9961-3893a1d6e851
 14 18e7f31e-c4f8-36d7-a4da-b496be9d9132
 15 38bae2d4-ff7c-1373-986a-9dd99665d2a1
 16 0c88b78d-0414-3b49-9c52-ae42be883f75

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 1263676624643313. Exactly this sequence comes out of new Random(196).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 34 of Run 34 (seed 83,105,000): new Random(83105000), Next(8,64) per post. The RNG predicts N = 16; the post has N = 16 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:23–10:24).
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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