201210112100 11camj

explained decrypted filler

seed 81

Metadata

Post ID: 11camj
Title: 201210112100 → 2012-10-11 21:00 on A858's clock
Posted (UTC): 2012-10-12 01:00:07
Timezone: UTC−4 · title 21:00 against posted 01:00 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,360 hex characters · 680 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210112100) = 2557960f188828ca78ea9fc542d68b62 (name+title)
GUIDs: 21
Filler GUID seed: new Random(81).Next(9) ✓ verified
Run: Run 36 (seed 335,015) (seed)
Draw: 7 · predicted N = 21 ✓
Machine boot: 2012-10-10 20:54–00:54 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 2 · 0
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: 1,360 hex characters = 680 bytes = 85 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210112100 (name+title). Key = MD5(password) = 2557960f188828ca78ea9fc542d68b62, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 21 GUIDs as hex (shown below).

Decrypted: GUID list

  1 fd2705fc-a7bd-09c3-8c0e-cf429542943a
  2 6a7b77f2-8d9a-5911-9dbd-a507391a4ee0
  3 afa397ec-9363-3b71-8fe6-81740ba79f67
  4 effe9344-7229-7608-99bf-4bf5dcefaa75
  5 f05112fe-d156-67f3-81dd-6b4f9cb0f951
  6 3fbed925-af4f-3189-83a4-88ff0aec8681
  7 30c3e5ff-08a5-1cac-8f83-a17cb77e754a
  8 5601d6c5-3011-0209-b81c-e7dcbc8b1ae3
  9 a63e5b6c-b842-8912-af4a-f8afe91325d2
 10 1b9f401c-4478-1349-b8a4-6b26ff3b725e
 11 05e43422-d082-8c06-ae28-24cda4285b41
 12 77476e2f-5973-6076-8980-2121d0c2237f
 13 3b74ecad-e4a6-2992-b43c-cbfdeb4100ad
 14 f96b6628-67a4-546a-bcac-b6ee465535f3
 15 d5cd8806-519b-642d-8e14-3fda963e29bd
 16 4f51af6c-d1f9-56a5-9257-b85ef74e577f
 17 c0c8db17-5e2a-8ebd-9003-f8ba106a5ce7
 18 dd5d4aa2-3c02-1ae5-9eb2-077c54baa2dc
 19 2186da11-3378-7c90-b699-b7baa671c3b4
 20 411df4e0-a345-63e4-af63-9de46f9db1fd
 21 cd9a4ffe-879e-5dc0-a7b3-7e490d45b0c5

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 053763108186256581765. Exactly this sequence comes out of new Random(81).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 7 of Run 36 (seed 335,015): new Random(335015), Next(8,64) per post. The RNG predicts N = 21; the post has N = 21 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-10-10 20:54–00:54).
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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