201210020520 10t4te

explained decrypted filler

3DES(name+title) ECB, 11 GUIDs, seed 442

Metadata

Post ID: 10t4te
Title: 201210020520 → 2012-10-02 05:20 on A858's clock
Posted (UTC): 2012-10-02 09:20:04
Timezone: UTC−4 · title 05:20 against posted 09:20 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 720 hex characters · 360 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210020520) = 801c13a4e0991afb5989fb605435dfe2 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 11
Filler GUID seed: new Random(442).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 4 · predicted N = 11 ✓
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: 720 hex characters = 360 bytes = 45 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210020520 (name+title). Key = MD5(password) = 801c13a4e0991afb5989fb605435dfe2, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 11 GUIDs as hex (shown below).

Decrypted: GUID list

  1 910504fd-0f40-5015-8eca-de5e6b4366eb
  2 07e48d5d-9e7e-46ac-931e-9ffcfd8d4e52
  3 cf50da6c-6111-60dd-8bde-aaab619f9bdb
  4 caea791a-0ce7-8dd3-87e8-5f2c23eb79e5
  5 87baaa5f-9d72-6b9a-ac02-c6edbc0d5a74
  6 3093858e-a6f5-757d-b0b5-20a51d98c7a8
  7 2eb4dded-02a6-886f-aa94-cf8af6b34f47
  8 a3eed4bb-f70f-1b2c-8594-b4b6636225a2
  9 1b33da72-b2a9-508b-8fed-619f1db9dca6
 10 f57aa84a-3f10-2940-afea-c8619ed3b75b
 11 923063fb-5817-833e-b74d-a5ebe8874e54

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 54686781528. Exactly this sequence comes out of new Random(442).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 4 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 11; the post has N = 11 ✓. 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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