201210052323 110zwd

explained decrypted filler

3DES(name+title) ECB, 9 GUIDs, seed 216

Metadata

Post ID: 110zwd
Title: 201210052323 → 2012-10-05 23:23 on A858's clock
Posted (UTC): 2012-10-06 03:23:47
Timezone: UTC−4 · title 23:23 against posted 03:23 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 592 hex characters · 296 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210052323) = 976eebf50b2ef651e317a7ccad4e5849 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 9
Filler GUID seed: new Random(216).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 274 · predicted N = 9 ✓
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: 6 · 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: 592 hex characters = 296 bytes = 37 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210052323 (name+title). Key = MD5(password) = 976eebf50b2ef651e317a7ccad4e5849, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 9 GUIDs as hex (shown below).

Decrypted: GUID list

  1 84230376-7c9f-542e-b86d-eb51eaa01159
  2 1df108aa-afcc-1106-9b92-dbab55dc7274
  3 47599ed5-eb69-6ab4-be27-cfb7560aba10
  4 3b70738e-eb9b-5f40-a69e-8dbc4f08cf3b
  5 b1969def-19d8-6a34-a126-c74d63bc9b54
  6 ff54e355-b242-208f-ae54-9dcdccd7ba03
  7 54890fee-8035-6426-a565-1dd9f120f4d0
  8 1c5179fb-4d50-7d77-b142-e698441dfd6d
  9 3cee5b80-d861-67be-b591-996e34e13e67

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 516562676. Exactly this sequence comes out of new Random(216).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 274 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 9; the post has N = 9 ✓. 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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