201210071645 113plw

explained decrypted filler

3DES(name+title) ECB, 16 GUIDs, seed 612

Metadata

Post ID: 113plw
Title: 201210071645 → 2012-10-07 16:45 on A858's clock
Posted (UTC): 2012-10-07 20:45:21
Timezone: UTC−4 · title 16:45 against posted 20:45 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,040 hex characters · 520 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210071645) = e31a30a33dccead8976b4bcb6dbb6147 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 16
Filler GUID seed: new Random(612).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 398 · predicted N = 16 ✓
Machine boot: 2012-09-22 10:16–10:36 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 2 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210071645 (name+title). Key = MD5(password) = e31a30a33dccead8976b4bcb6dbb6147, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 16 GUIDs as hex (shown below).

Decrypted: GUID list

  1 e5d42166-f1c8-4c49-9620-e19368c482be
  2 9638db3d-2ced-3ee5-8cd9-f410fb8c9281
  3 7d52798e-5da4-48e7-8e0e-7276c88abc16
  4 a058c09f-920d-144a-a032-708d223180b8
  5 943343ce-0718-45bf-8bc7-fdc643caf08a
  6 d3b434f1-48dd-3498-b422-bb08b5677ba5
  7 94bb2700-e076-1620-b546-2e0d5eb15309
  8 11cfce33-489e-4fa7-900a-176d24e2bd8c
  9 c09300a9-a409-6025-a50c-8abd21486c57
 10 c1a9de1a-fc71-8da8-98bb-a4ff2fca9155
 11 545c545d-a339-10e6-a9cf-9915d16dfa86
 12 bde2bee8-5e1b-26ca-9909-c16bde2c8dee
 13 43662c46-90c8-3c77-85ea-0ad5b5b54ddb
 14 6235a80f-9dba-7fd8-9e5b-90f205e796f6
 15 f5cc5a1d-6036-3650-aae9-54e65cd7a50d
 16 7699ce84-65e5-208f-b0e3-98c78d5f2b38

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 4341431468123732. Exactly this sequence comes out of new Random(612).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 398 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 16; the post has N = 16 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:16–10:36).
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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