201309152059 1mgvdb

explained decrypted filler

seed 930

Metadata

Post ID: 1mgvdb
Title: 201309152059 → 2013-09-15 20:59 on A858's clock
Posted (UTC): 2013-09-16 00:59:56
Timezone: UTC−4 · title 20:59 against posted 00:59 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,552 hex characters · 776 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201309152059) = 41211f6213db57b6fc53ad4de82b63dd (name+title)
GUIDs: 24
Filler GUID seed: new Random(930).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 80 · predicted N = 24 ✓
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: 1,552 hex characters = 776 bytes = 97 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309152059 (name+title). Key = MD5(password) = 41211f6213db57b6fc53ad4de82b63dd, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 24 GUIDs as hex (shown below).

Decrypted: GUID list

  1 aab70f52-ad81-5565-be2c-024acc01927e
  2 20999336-d4aa-694a-855d-3479a17e1b19
  3 dfb5ed5e-3683-7ee0-8a0b-c188e11ed777
  4 024e8cbe-ed15-0d97-ab06-244b9fe63b16
  5 4b7cdc3c-df27-070a-b658-9d9803c2681e
  6 1070e5ee-a3b2-23db-837d-955c08665bc6
  7 7d764cf6-331f-5cc5-9ca8-a81760217939
  8 9ee168b6-756d-0472-9c27-9d9efabd14b0
  9 b94f9625-f579-0970-952a-6d50b837ef39
 10 76f89859-4084-12a2-b8cf-c8da777c41cc
 11 8492d4da-3d50-4206-bbf4-6c6e3990b5b6
 12 0d070d21-144f-4207-a92d-74900a5defa4
 13 0e9ae529-f0cc-8e28-a4ee-a097b0d1b759
 14 a0ab2708-6899-2f88-8023-016b7498ee52
 15 ad83c11a-7712-8879-893b-fc7740e0c975
 16 ee7f556d-47f9-7047-b617-83ffc75caa2d
 17 1946a13c-5645-7782-a9d8-a85e09e71794
 18 f662bddc-1773-5025-ab0a-d2f428cdfe3e
 19 e9b142d6-58b6-7675-9ad5-28ee4a1a2f3f
 20 bd8c92c5-8946-3260-86c0-6863c8769d83
 21 05e74338-fb7d-3e83-8507-6bb390cac440
 22 9bd14243-5139-0316-b93e-78ea2e67abb6
 23 fa7a7770-aac2-1ca4-a075-9131b81f1931
 24 d6399f0f-d337-8bc6-b7dc-f8349f449e84

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 567002500144828775733018. Exactly this sequence comes out of new Random(930).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 80 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) per post. The RNG predicts N = 24; the post has N = 24 ✓. 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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