201209212059 10a0k9

explained decrypted filler

3DES(name+title) ECB, 14 GUIDs, seed 811

Metadata

Post ID: 10a0k9
Title: 201209212059 → 2012-09-21 20:59 on A858's clock
Posted (UTC): 2012-09-22 01:00:00
Timezone: UTC−4 · title 20:59 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: 912 hex characters · 456 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201209212059) = daea0f0e7c575f8be0fdda38c0e9ec58 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 14
Filler GUID seed: new Random(811).Next(9) ✓ verified
Run: Run 33 (seed 1,220,410,968) (seed)
Draw: 0 · predicted N = 14 ✓
Machine boot: 2012-09-07 21:49–21:59 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 15 · 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: 912 hex characters = 456 bytes = 57 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209212059 (name+title). Key = MD5(password) = daea0f0e7c575f8be0fdda38c0e9ec58, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 14 GUIDs as hex (shown below).

Decrypted: GUID list

  1 19ed30d6-6bd9-30ef-8eec-74d563c887a6
  2 c84dea6c-6c6a-79c9-ae3f-150906f09b6f
  3 b766bab9-784d-5e35-84c3-a253da16468a
  4 4b73935b-bf8a-5ffe-9797-1d19a4549d44
  5 e298cf81-cf41-3c33-85c7-edaa44025933
  6 cc09c803-f289-260c-8638-8812c4cfc63b
  7 fbd303bf-3c6c-2f3c-a3ca-1b3971ab9a89
  8 3e8a5785-7e7a-2453-ad45-a89e3aab6f57
  9 32b64a90-adba-2016-b159-add34b310ae9
 10 a52b1a07-8566-25c4-9591-b08ef66d7c4d
 11 2f9bb353-d701-7de4-8211-f328fb74576a
 12 a7cd8aeb-16a3-53b5-8c99-0a14e5883f5a
 13 6291cb9c-b68c-14c9-8f6a-a488d586b9e9
 14 85e36877-9c18-3c30-bd08-7c4fee0193ad

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 37553222227513. Exactly this sequence comes out of new Random(811).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 0 of Run 33 (seed 1,220,410,968): new Random(1220410968), Next(8,64) per post. The RNG predicts N = 14; the post has N = 14 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-07 21:49–21:59).
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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