201212031741 148537

explained decrypted filler

seed 294

Metadata

Post ID: 148537
Title: 201212031741 → 2012-12-03 17:41 on A858's clock
Posted (UTC): 2012-12-03 22:41:05
Timezone: UTC−5 · title 17:41 against posted 22:41 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 656 hex characters · 328 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201212031741) = 0a83236b187114be8846b0eae66286bf (name+title)
GUIDs: 10
Filler GUID seed: new Random(294).Next(9) ✓ verified
Run: Run 39 (seed 1,106,402,812) (seed)
Draw: 6 · predicted N = 10 ✓
Machine boot: 2012-11-20 22:02–00:02 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 1 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: 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 = A858DE45F56D9BC9201212031741 (name+title). Key = MD5(password) = 0a83236b187114be8846b0eae66286bf, 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 7fb07044-c77e-2fdc-be4e-bb6d5e42b3ae
  2 1ff2816e-ff94-086c-8c4f-6bb3a92f5fc6
  3 506bafac-fd22-2656-ad99-27f1e6b9ec0f
  4 b1fff826-5b1e-25f4-a290-589b84df6214
  5 ac1bf6b7-6d08-8b46-985b-28cb2f70b719
  6 253c7731-b73b-4d1f-ac07-aeadee4d6f79
  7 99c1e66e-7d82-57da-9a60-5b3469965080
  8 50cf9d10-91a0-8dab-8558-5e375abcce7f
  9 34cf4246-3e38-338b-91d5-5c2d5de0c7d4
 10 5824a962-c822-6b17-bc9f-c95db253f0ac

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 2022845836. Exactly this sequence comes out of new Random(294).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 6 of Run 39 (seed 1,106,402,812): new Random(1106402812), 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 2012-11-20 22:02–00:02).
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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