201209212210 10a3vs

explained decrypted filler

3DES(name+title) ECB, 14 GUIDs, seed 838

Metadata

Post ID: 10a3vs
Title: 201209212210 → 2012-09-21 22:10 on A858's clock
Posted (UTC): 2012-09-22 02:10:06
Timezone: UTC−4 · title 22:10 against posted 02:10 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 912 hex characters · 456 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201209212210) = 6683ad38a6d77b42ce5813a0aaaa4eef (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 14
Filler GUID seed: new Random(838).Next(9) ✓ verified
Run: Run 33 (seed 1,220,410,968) (seed)
Draw: 7 · predicted N = 14 ✓
Machine boot: 2012-09-07 21:49–21:59 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 3 · 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: 912 hex characters = 456 bytes = 57 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209212210 (name+title). Key = MD5(password) = 6683ad38a6d77b42ce5813a0aaaa4eef, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 14 GUIDs as hex (shown below).

Decrypted: GUID list

  1 cf5c5eb1-662c-4805-aa69-b15b39c31408
  2 bebc4539-ae51-6277-ba39-cd5e8fd59893
  3 047a41e0-26ed-45d4-9137-30411770b022
  4 314c03a4-3452-3289-939c-a583f59d7892
  5 6668411d-0e4b-4c7e-9754-5967b55dba34
  6 86b2bfa6-f88d-7738-80d2-68660cb568e1
  7 4f121550-816c-32f6-8c5a-9a1f6942c022
  8 fe3710f4-5530-72c2-900a-56d185b29efe
  9 f0ef5a6d-a81b-55a1-b59c-4f3cd7896afe
 10 6f2dbcf8-359a-2cfd-9219-90f7119e839b
 11 fcbc7b37-6d98-62f6-8811-17ad8357eae7
 12 42fe011c-05db-6933-9ce4-b8c0a9b16e0f
 13 61f1c058-2007-680c-b8b8-19946ca3c38c
 14 0c4f7dca-4fd8-3d69-a633-95ecef2f00d9

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 46434737526663. Exactly this sequence comes out of new Random(838).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 7 of Run 33 (seed 1,220,410,968): new Random(1220410968), Next(8,64) per post. The RNG predicts N = 14; the post has N = 14 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-07 21:49–21:59).
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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