201210021740 10u7o9

explained decrypted filler

3DES(name+title) ECB, 10 GUIDs, seed 456

Metadata

Post ID: 10u7o9
Title: 201210021740 → 2012-10-02 17:40 on A858's clock
Posted (UTC): 2012-10-02 21:40:35
Timezone: UTC−4 · title 17:40 against posted 21:40 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 656 hex characters · 328 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210021740) = 3fbaa4f2449f4461522aeedb8f50be75 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 10
Filler GUID seed: new Random(456).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 41 · predicted N = 10 ✓
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: 656 hex characters = 328 bytes = 41 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210021740 (name+title). Key = MD5(password) = 3fbaa4f2449f4461522aeedb8f50be75, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 10 GUIDs as hex (shown below).

Decrypted: GUID list

  1 ee0e2801-99df-898b-8fd1-8ba32518bdc5
  2 f1ecfe92-1ec7-56c3-a66b-dc34c2f48124
  3 d049ab76-cc4d-4f3e-8d09-f9658dbaf4ca
  4 b2e0739d-83b0-7bc8-986d-3458b89e7de4
  5 1fb72ee5-5548-05fc-ba6f-5a0d63eba50a
  6 5cedf7f0-92c9-07e7-83ba-8f1b441eafaa
  7 1d7f4b82-ddfa-1d3d-b8fa-d9d0f927dbbb
  8 501d07dc-b9b4-172c-b6da-c28ed5bc6c32
  9 227b92f3-6e8b-34a2-98ae-3eb88c0996ff
 10 478777e9-d7fe-3042-984a-cc106a1242de

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 8547001133. Exactly this sequence comes out of new Random(456).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 41 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 10; the post has N = 10 ✓. 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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