201210030301 10v4n8

explained decrypted filler

3DES(name+title) ECB, 15 GUIDs, seed 136

Metadata

Post ID: 10v4n8
Title: 201210030301 → 2012-10-03 03:01 on A858's clock
Posted (UTC): 2012-10-03 07:01:04
Timezone: UTC−4 · title 03:01 against posted 07:01 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(A858DE45F56D9BC9201210030301) = 0d608e7a007a94f6f20c0a613ab1db19 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 15
Filler GUID seed: new Random(136).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 69 · 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 = A858DE45F56D9BC9201210030301 (name+title). Key = MD5(password) = 0d608e7a007a94f6f20c0a613ab1db19, 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 956e4a4f-ffb4-650e-a5f7-0a9eaee7ef6a
  2 64c45b5d-e930-61f0-9a56-3fe1e5721841
  3 a02d22c6-58af-7c08-9ad1-0240ac5cf574
  4 4dfa76ff-6714-53be-8de7-d01a195aac72
  5 02668154-366a-5135-9678-6ea8ed4fa858
  6 bff6618c-3825-39a6-8b6f-708d09149e5f
  7 b3eb3253-b675-7306-8939-711bf15a555d
  8 145857ef-26aa-6a31-8d75-f18517f3ee0e
  9 ecc957eb-b6e5-7bf4-9cb1-5bf104d610e7
 10 2d3e0322-0feb-3fbf-aea6-fbac68cae623
 11 d605f704-5179-4ff5-9d81-1dd38e109c73
 12 977c5c45-d0fb-5383-aa4c-e5f2b043e229
 13 c727293c-433d-1706-9b6c-b542904a2489
 14 9b9a1fde-da80-24be-bfdb-5e115c51edaf
 15 aa25a406-c834-135d-b213-ec85ac9228f0

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 667553767345121. Exactly this sequence comes out of new Random(136).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 69 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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