201210031541 10w4dr

explained decrypted filler

3DES(name+title) ECB, 9 GUIDs, seed 544

Metadata

Post ID: 10w4dr
Title: 201210031541 → 2012-10-03 15:41 on A858's clock
Posted (UTC): 2012-10-03 19:41:28
Timezone: UTC−4 · title 15:41 against posted 19:41 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(A858DE45F56D9BC9201210031541) = 86ee06f3bdf666b36abb04d12389a0d5 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 9
Filler GUID seed: new Random(544).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 107 · 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: 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: 592 hex characters = 296 bytes = 37 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210031541 (name+title). Key = MD5(password) = 86ee06f3bdf666b36abb04d12389a0d5, 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 3c869435-0fac-8134-ae06-b41bf2be7b14
  2 4a06834f-d0a1-332b-b687-0763f3170530
  3 c34bdc9e-21d8-0e15-bd47-403a6c993558
  4 79b770d8-4bd2-6c5e-a388-d76fa91bd205
  5 7ef51d49-9ff4-78a2-8ee5-0d86ac42f7dc
  6 ce7d56f4-90a9-8ed0-a3ba-4aac1ccb22dd
  7 a54661a1-09ab-5f68-a2a5-0f8614d73238
  8 8929c69b-fe99-3def-abfc-44f39064ec06
  9 5b8f5281-6b04-2b96-b927-24a6ec124c62

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 830678532. Exactly this sequence comes out of new Random(544).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 107 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

Related