201309151959 1mgqpj

explained decrypted filler

seed 893

Metadata

Post ID: 1mgqpj
Title: 201309151959 → 2013-09-15 19:59 on A858's clock
Posted (UTC): 2013-09-15 23:59:56
Timezone: UTC−4 · title 19:59 against posted 23:59 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(A858DE45F56D9BC9201309151959) = 48e94a3d9c4542b0e47baeb72c0421ab (name+title)
GUIDs: 20
Filler GUID seed: new Random(893).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 79 · 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: 3 · 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 = A858DE45F56D9BC9201309151959 (name+title). Key = MD5(password) = 48e94a3d9c4542b0e47baeb72c0421ab, 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 b05c89c5-ecee-2ea3-bed1-3ad2324ee8c5
  2 8c455336-32c0-78f6-9f5a-8f0c3a8f8f75
  3 f1890995-b124-8695-b6bf-d7d4191d8261
  4 54cc8258-2111-1909-81e4-7fc299ff3ba0
  5 a3b9de46-918b-3e94-a5c4-8baa3814b28b
  6 f592bb9f-de4f-86e4-b975-f9747053766c
  7 80c142e8-a965-07c1-ae0e-490c04fd8d2f
  8 63763f73-9b9a-497f-8b8b-0753ef2dad70
  9 51a63840-d2bc-4f24-9475-5a488539ab6a
 10 4e36c71a-996e-55ae-969e-2bfca648e390
 11 07aa04dc-22c2-1b1c-bcc6-2352aa3d1666
 12 f72a27dd-0688-543e-bf2f-705867f7e57c
 13 0affcd2a-16bb-419a-bbf4-291985db7f0a
 14 4e54546a-3344-0434-8d10-805cc7b71d3f
 15 7bdfcfee-b053-0ac2-a289-bd3d224c9333
 16 cf465321-1f24-61c4-b9ee-e1b781ce0b1c
 17 624cc60f-a80e-29b1-b148-cde5985ad9ff
 18 7c9b1f56-1b9d-50ad-bcec-c1d336274185
 19 8d8698b0-38d9-75a7-9bf6-e59cb0af9763
 20 d004503e-1c9c-0218-a36c-913f8e3fcab4

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 27813804451540062570. Exactly this sequence comes out of new Random(893).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 79 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

Related