201210061944 112bun

explained decrypted filler

3DES(name+title) ECB, 8 GUIDs, seed 741

Metadata

Post ID: 112bun
Title: 201210061944 → 2012-10-06 19:44 on A858's clock
Posted (UTC): 2012-10-06 23:44:34
Timezone: UTC−4 · title 19:44 against posted 23:44 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 528 hex characters · 264 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210061944) = 4c2643080c3fe80768d86818ce8c863f (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 8
Filler GUID seed: new Random(741).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 335 · predicted N = 8 ✓
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: 3 · 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: 528 hex characters = 264 bytes = 33 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210061944 (name+title). Key = MD5(password) = 4c2643080c3fe80768d86818ce8c863f, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 8 GUIDs as hex (shown below).

Decrypted: GUID list

  1 660efc51-7d0f-7ba0-af8f-05c76c959e42
  2 0496ba02-0243-23ba-b780-de780a7de42f
  3 254f9934-0e66-632b-9128-6b142f1301b2
  4 acba3c44-bc4b-6177-aba3-cad51418d98b
  5 19032d7c-104c-6e0d-aefd-5a64a1d47dd2
  6 e999868e-5104-1481-ae87-f3197fff46cf
  7 84e04f7d-b363-825b-a273-f844884976cb
  8 d913eee6-5417-178a-9b8e-26864ff5288b

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 72666181. Exactly this sequence comes out of new Random(741).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 335 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 8; the post has N = 8 ✓. 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