201208131830 y4ylh

explained decrypted filler

3DES(name+name) ECB, 21 GUIDs, seed 295

Metadata

Post ID: y4ylh
Title: 201208131830 → 2012-08-13 18:30 on A858's clock
Posted (UTC): 2012-08-13 09:27:22
Timezone: UTC+9 · title 18:30 against posted 09:27 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,360 hex characters · 680 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9A858DE45F56D9BC9) = 0dcc4bd9e114ebc42078977dc9125404 (name+name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 21
Filler GUID seed: new Random(295).Next(9) ✓ verified
Run: Run 22 (seed 528,385,484) (seed)
Draw: 74 · predicted N = 21 ✓
Machine boot: 2012-07-27 19:02–19:13 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 6 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+namerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,360 hex characters = 680 bytes = 85 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9A858DE45F56D9BC9 (name+name). Key = MD5(password) = 0dcc4bd9e114ebc42078977dc9125404, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 21 GUIDs as hex (shown below).

Decrypted: GUID list

  1 36e37999-2f58-7994-aec7-86d45456df94
  2 c3a033c2-c5e4-37c2-9aea-0bdc1436edde
  3 bf613c60-8fe5-843a-8edc-13820266cf0f
  4 9f50489a-1c7b-4d0b-8822-1b2d2d27b562
  5 3a2b2f88-0b3e-344a-bd51-50e58f513626
  6 45d8cd0e-cb4f-34c0-b47d-582fbc187df1
  7 43f889e1-2ee5-0247-a35f-ebdaa41c0090
  8 b0aef6ec-7133-32cc-a838-a9ccce2f5cc6
  9 56f3dd0a-4fee-4f7d-b5dc-95a432e25aa6
 10 3b0118cd-35b2-090f-8099-963be9d394c0
 11 47b8d412-0058-52a4-998a-6325a6334f3b
 12 8ac010a3-111c-7d7c-ada9-589ddd7e8b2c
 13 6015537a-c65e-3529-a570-1a79691cd0b4
 14 026a4b96-9848-8aa8-afef-cb87299edca6
 15 7a27c1fa-f5a4-417b-af8f-ad8170813c8b
 16 3c3f7b4f-f317-21d2-b754-187d16b86f21
 17 a7329250-af3d-778c-80b0-0773be4863a3
 18 8957a0c9-65bb-87f8-81f1-804bea8fb4f6
 19 20012ce7-b8cf-5282-a219-90ea63acfc08
 20 4811e621-8890-41e7-b659-7dca33a37d40
 21 78f4c541-8124-0a7b-adb8-4373a351ebc2

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 738433034057384278540. Exactly this sequence comes out of new Random(295).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 74 of Run 22 (seed 528,385,484): new Random(528385484), Next(8,64) per post. The RNG predicts N = 21; the post has N = 21 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-07-27 19:02–19:13).
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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