201309160459 1mhnun

explained decrypted filler

seed 372

Metadata

Post ID: 1mhnun
Title: 201309160459 → 2013-09-16 04:59 on A858's clock
Posted (UTC): 2013-09-16 08:59:55
Timezone: UTC−4 · title 04:59 against posted 08:59 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,296 hex characters · 648 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201309160459) = 727cc71f0e5e29b355f0da7d16eebda1 (name+title)
GUIDs: 20
Filler GUID seed: new Random(372).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 88 · predicted N = 20 ✓
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: 2 · 0
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,296 hex characters = 648 bytes = 81 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309160459 (name+title). Key = MD5(password) = 727cc71f0e5e29b355f0da7d16eebda1, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 20 GUIDs as hex (shown below).

Decrypted: GUID list

  1 94eb809e-7da4-07f4-a91e-c2ae84883b9c
  2 b907ba34-1650-8259-9a51-d21ece3bcd74
  3 d7e7caac-7550-7529-83c1-afacf5c41d35
  4 1dfabe9d-1886-89db-83ed-b00391e1bf3e
  5 bd6da77d-9c0f-15e9-8a86-52fb4c9da05e
  6 b42acf80-dc8e-559d-a458-f9877390f248
  7 65052db8-f062-5dd4-8e28-e2730055f0f7
  8 4e0e0448-15cb-0dc0-ab1e-b22cdbb35a8b
  9 ab72f10e-c12c-005e-acde-fc9140550162
 10 649e8852-b164-424d-9450-bf1e1dc66126
 11 db98f90d-e730-3ef8-861e-e6e8a8ce5fb8
 12 e3ebe1a1-0612-83b1-815c-00f88bf357fd
 13 01bc9397-a896-32cc-98c0-696cd0a1a599
 14 67f8242f-b457-05bf-b943-79921e600c8a
 15 a6f20f2c-9080-3857-9f47-0b5b13f4193f
 16 c15c6ea6-4172-34b2-89e2-8b3dc83b2e68
 17 6c199f1c-e1e8-2171-a383-f812a17af278
 18 150c11dd-2e4e-59c4-b2f8-acb0023a2e8f
 19 afa63943-ce7a-6c40-982e-3d63c91d0599
 20 56c1e2a2-86b4-3ec9-8fb9-0fffc37fe572

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 08781550043830332563. Exactly this sequence comes out of new Random(372).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 88 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) per post. The RNG predicts N = 20; the post has N = 20 ✓. 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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