201309221832 1mx5m1

explained decrypted filler

seed 292

Metadata

Post ID: 1mx5m1
Title: 201309221832 → 2013-09-22 18:32 on A858's clock
Posted (UTC): 2013-09-22 22:32:52
Timezone: UTC−4 · title 18:32 against posted 22:32 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 272 hex characters · 136 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201309221832) = 3e056c77a6142c6b2eefabb2132ac773 (name+title)
GUIDs: 4
Filler GUID seed: new Random(292).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 126 · predicted N = 4 ✓
Machine boot: 2013-09-12 09:30–10:30 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 8 · 3
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

2DE4683A5AB4DC23 7AD2CBDFC40B8FE9 C42137443C2567F2 CB4157852BD108DC D048C4489590429D ACC21193EE5386CF A2642B09003433C1 649D3387A1F9F23C 9832C19506FAFCB1 E86E348C28C94AF1 FCEB8EEA49AE333A A06BBDED33CCF85E 34E8DFAA6C6638A5 E94F9EF4BF7438A2 79AE2097CDF3D9E3 5BE3973A1DD25F42 28E65266C58DDAE0

Read the ciphertext. Strip whitespace: 272 hex characters = 136 bytes = 17 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309221832 (name+title). Key = MD5(password) = 3e056c77a6142c6b2eefabb2132ac773, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 4 GUIDs as hex (shown below).

Decrypted: GUID list

  1 8521acdb-4788-2b0a-a0f5-7522b55c8e37
  2 2febb7e5-5afe-4f42-988b-fde65f11dd82
  3 92ca16e8-7154-7f34-a363-dd41ec4822a7
  4 ee869ee1-6ec5-7628-b807-57a890a739c7

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 2477. Exactly this sequence comes out of new Random(292).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 126 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) per post. The RNG predicts N = 4; the post has N = 4 ✓. The seed is the machine's uptime in ms when the app started (boot 2013-09-12 09:30–10:30).
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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