201210021020 10tf3l

explained decrypted filler

3DES(name+title) ECB, 15 GUIDs, seed 202

Metadata

Post ID: 10tf3l
Title: 201210021020 → 2012-10-02 10:20 on A858's clock
Posted (UTC): 2012-10-02 14:20:16
Timezone: UTC−4 · title 10:20 against posted 14:20 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 976 hex characters · 488 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210021020) = b91b758a84abc3928458e819b31b6c9b (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 15
Filler GUID seed: new Random(202).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 19 · predicted N = 15 ✓
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: 1 · 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: 976 hex characters = 488 bytes = 61 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210021020 (name+title). Key = MD5(password) = b91b758a84abc3928458e819b31b6c9b, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 15 GUIDs as hex (shown below).

Decrypted: GUID list

  1 b0ef801e-9ff2-27ef-9fee-8146a5dfdd07
  2 bbb680ec-f9d4-0911-9e93-5675aa580d4d
  3 d305662b-31ea-81a2-871a-e0929a1d0590
  4 1c0f8600-fb2a-6e35-8397-c24995f14edb
  5 0e35c83d-8c43-30af-b93e-c551dc7b0902
  6 7e2b4c3e-f181-07eb-8d65-f0327d9e874f
  7 aea9e417-094e-3bd4-b796-734a5dbc0558
  8 21f56aed-5f12-7882-9ee3-e483a82df3b1
  9 f4dda51b-e46c-83f5-9be6-c1d52f84aa15
 10 24b8ed0b-1dc4-617d-ab91-76003cdc06a2
 11 d8e7c773-e696-12ae-b820-8f262a4c462f
 12 01958d4f-3501-159a-9fa7-fd3c4ff521b9
 13 a7fe6302-e0cd-423f-a9cc-19d394cba4b3
 14 7fd43bbd-a7b7-512a-8b23-52f3184d84e8
 15 2c60cbab-3b7d-3c98-b5c1-49f6c1b0987a

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 208630378611453. Exactly this sequence comes out of new Random(202).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 19 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 15; the post has N = 15 ✓. 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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