201210020500 10t4cg

explained decrypted filler

3DES(name+title) ECB, 16 GUIDs, seed 486

Metadata

Post ID: 10t4cg
Title: 201210020500 → 2012-10-02 05:00 on A858's clock
Posted (UTC): 2012-10-02 09:00:03
Timezone: UTC−4 · title 05:00 against posted 09:00 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,040 hex characters · 520 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210020500) = 270e48787e3fe7763bde6f5511ff99cd (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 16
Filler GUID seed: new Random(486).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 3 · predicted N = 16 ✓
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: 1 · 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: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210020500 (name+title). Key = MD5(password) = 270e48787e3fe7763bde6f5511ff99cd, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 16 GUIDs as hex (shown below).

Decrypted: GUID list

  1 45a1b25f-60a5-5b69-bb3a-1a4002447209
  2 e29e21ba-cb16-3554-af54-801ca5c8126a
  3 93f97e3a-a6fb-4ab4-a581-3b171375cf67
  4 a29b9634-ca12-2943-b0f3-e97936d57c42
  5 021dbe90-cf5d-537f-aeb0-598b3ccb1845
  6 f957d9a4-f452-2734-9c5b-8ccf70a1b98d
  7 6387ee7d-1370-5fa7-a200-86e152f62387
  8 77c45f07-477e-2e38-bd89-905e4edd6bbb
  9 7a2cdb8c-e2a1-0857-9c1e-43d322d87e5b
 10 f6bed08e-4e2a-480e-b799-cbcf85f283e8
 11 8e6c1438-9009-37ec-8ec4-4ab836314c9c
 12 b137cd2e-b09e-87a8-ab19-edba8900b08f
 13 13547861-2b63-6075-9a6a-9cd14691bef4
 14 9c15604a-6733-2a96-8ca1-d9a785a8b7d6
 15 a8f09fcf-5b44-1eae-a68f-b5bb709c31fe
 16 b58abee5-cae5-43b3-b414-0e701e87ad28

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 5342525204386214. Exactly this sequence comes out of new Random(486).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 3 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 16; the post has N = 16 ✓. 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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