201211082135 12ut4w

explained decrypted filler

seed 782

Metadata

Post ID: 12ut4w
Title: 201211082135 → 2012-11-08 21:35 on A858's clock
Posted (UTC): 2012-11-08 13:35:35
Timezone: UTC+8 · title 21:35 against posted 13:35 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,232 hex characters · 616 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201211082135) = abd8ce59045e92f2cdbebc691ae9e144 (name+title)
GUIDs: 19
Filler GUID seed: new Random(782).Next(9) ✓ verified
Run: Run 38 (seed 1,045,884,937) (seed)
Draw: 127 · predicted N = 19 ✓
Machine boot: 2012-10-11 03:41–03:51 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 10 · 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: 1,232 hex characters = 616 bytes = 77 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201211082135 (name+title). Key = MD5(password) = abd8ce59045e92f2cdbebc691ae9e144, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 19 GUIDs as hex (shown below).

Decrypted: GUID list

  1 46040523-d923-293e-9708-a7cc736029cb
  2 81b1d751-86d3-28c5-a190-cea18c65ded7
  3 0e6f3f92-de54-3250-aa5f-c2a4b535d9c0
  4 d397f787-a6a2-40be-80fb-5f6339ca6210
  5 1b7fa8c9-db73-25b0-a25f-a15960c4a366
  6 2baba2b7-188e-8956-94eb-38cc254a7ba2
  7 98eada39-fa2a-2ac7-a9a8-8463bd2eb4c1
  8 e2586e2e-5422-6125-a8dc-39133d9ad0b9
  9 1df044fa-51a4-6a32-9ff4-1440039d09ee
 10 38482548-fa9a-5091-b88a-48dbd5fcc76b
 11 8f8c33f6-3e09-3346-8582-c0c5acf40192
 12 a9c4060d-147a-8857-83ba-096e32fccaf8
 13 8c6055c8-d264-1f61-bcdf-5322609097fc
 14 5ed45e04-4d44-2231-b6ce-2997b56c0281
 15 78a58c10-8e51-3a22-aad5-39d6adf13655
 16 df69920a-a83d-3b30-991c-c09d34231709
 17 58b1de3c-e8da-59d7-85e5-81fdf924482c
 18 a4055d10-175d-7e07-83b4-38ba5b292bc8
 19 7e047fb2-f24a-7f97-abce-afcf753b701e

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 2234282665381233577. Exactly this sequence comes out of new Random(782).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 127 of Run 38 (seed 1,045,884,937): new Random(1045884937), Next(8,64) per post. The RNG predicts N = 19; the post has N = 19 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-10-11 03:41–03:51).
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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