201309231232 1myufu

explained decrypted filler

seed 350

Metadata

Post ID: 1myufu
Title: 201309231232 → 2013-09-23 12:32 on A858's clock
Posted (UTC): 2013-09-23 16:32:52
Timezone: UTC−4 · title 12:32 against posted 16:32 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(A858DE45F56D9BC9201309231232) = 7db53e0411d00e52d75581a2e33b14cd (name+title)
GUIDs: 20
Filler GUID seed: new Random(350).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 129 · predicted N = 20 ✓
Machine boot: 2013-09-12 09:30–10:30 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 5 · 0
Tags: automated (decryptable)2013Encrypted 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 = A858DE45F56D9BC9201309231232 (name+title). Key = MD5(password) = 7db53e0411d00e52d75581a2e33b14cd, 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 371a671d-7df9-58ba-974e-9cc5b20ccf06
  2 be8b6838-0be2-4dc7-b07a-3fe3ddc4b166
  3 275184f3-4b60-3f98-90f9-90ea0b3416e0
  4 b7d5d3a1-b2c8-247f-865e-457ba089bc33
  5 d70ce5b1-34e9-2857-9cce-f95887363575
  6 c155b942-4865-3f94-af45-d8127bbbab59
  7 41f21e17-e4b7-66d8-a6ec-0e2320116f8c
  8 e795c934-ce59-0f75-a582-dc917b22f341
  9 7a5e3d45-48c2-2fa5-b105-f670d43a9097
 10 b81a5b5b-1086-3372-840e-abef246797af
 11 5a422d14-5c10-1cd3-8fe3-60f6f4c9aa2d
 12 620cfafb-f9a0-68ef-b332-03e60db82a20
 13 dda61ca4-de24-234c-984c-b15d2aabe010
 14 b009acde-44e9-5fdf-ba44-a117c1c67b4f
 15 bb1d39f6-f245-83d0-aad2-02254e42f48a
 16 933fa135-94f8-5f76-800f-8e873d4f65bb
 17 0c315d27-8c8c-890e-8315-d4d7cb6f7c0e
 18 76a44066-9ddf-8f20-8c55-29da67e784e8
 19 b311ab4b-2891-1551-83bf-afc722d42748
 20 d4cf663c-1aff-7892-8ad2-3f48ed707818

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 54322360231625858817. Exactly this sequence comes out of new Random(350).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 129 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) 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 2013-09-12 09:30–10:30).
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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