201210070644 1130cn

explained decrypted filler

3DES(name+title) ECB, 12 GUIDs, seed 731

Metadata

Post ID: 1130cn
Title: 201210070644 → 2012-10-07 06:44 on A858's clock
Posted (UTC): 2012-10-07 10:44:59
Timezone: UTC−4 · title 06:44 against posted 10:44 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 784 hex characters · 392 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210070644) = db1479c81f64987e9c95ce75bd71b235 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 12
Filler GUID seed: new Random(731).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 368 · predicted N = 12 ✓
Machine boot: 2012-09-22 10:16–10:36 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 7 · 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: 784 hex characters = 392 bytes = 49 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210070644 (name+title). Key = MD5(password) = db1479c81f64987e9c95ce75bd71b235, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 12 GUIDs as hex (shown below).

Decrypted: GUID list

  1 54fdaaad-3e18-5ade-8481-f2024a21a07f
  2 0fdc8698-5410-26df-b145-4523d9a34e4f
  3 8ef7dec5-430a-6a45-b66a-3d4687c356e5
  4 2f932443-bc84-5952-b939-0613aa213fb4
  5 5777ae72-9c24-20fb-9c0c-6c56f46c9300
  6 b3e550d0-6599-337b-977b-968bfff7940d
  7 5d555177-6bc2-3abe-b534-b70c51528827
  8 f498f80e-7c9b-1db8-aef7-ae85bd4eadbc
  9 77601ec0-cebd-38e8-a5f0-ccdac80a06b9
 10 6c30924f-01da-7bf5-bde8-d89333ca7f10
 11 65fb106b-8ecf-7890-a68e-d10de37812bf
 12 4ef0f268-7ece-136c-bc76-9ee493534f78

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 526523313771. Exactly this sequence comes out of new Random(731).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 368 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 12; the post has N = 12 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:16–10:36).
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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