201206261142 vn4pi

explained decrypted filler

3DES(name) ECB, 16 GUIDs, seed 555

Metadata

Post ID: vn4pi
Title: 201206261142 → 2012-06-26 11:42 on A858's clock
Posted (UTC): 2012-06-26 18:40:39
Timezone: UTC−7 · title 11:42 against posted 18:40 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(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 16
Filler GUID seed: new Random(555).Next(9) ✓ verified
Run: Run 3 (seed 1,063,142,882) (seed)
Draw: 64 · predicted N = 16 ✓
Machine boot: 2012-06-14 10:25–10:26 (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: namerun: 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 = A858DE45F56D9BC9 (name). Key = MD5(password) = 34a14a42e98ff96095af56604e290cae, 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 11065c8f-6cf2-6009-a414-12188a4e268f
  2 9e0e8ec0-dbb9-5846-a180-a79629aa72eb
  3 e736ea04-e97a-6972-b37e-5c42edb9f28c
  4 71c8b875-c20b-090a-9a8e-52720816edb0
  5 5d95376d-c324-7c28-9adf-28b317ef9a84
  6 ef9519d4-5b5f-50c5-be19-c92123ef0b1b
  7 c4ac8057-bcc6-5893-8cca-b3d2b34d3726
  8 bc85922f-0e9c-7121-947f-a5438c3d8654
  9 3019e00e-14f4-5584-b0bd-8e5c8f04fe7c
 10 279a63b8-0303-8cca-8610-efb4636d27a9
 11 43f3b9f0-2438-18a4-9472-53ad31f88c59
 12 133e1108-6364-61e9-b0f6-0006bcb5609c
 13 f186d385-13ec-1278-b669-6d70ae3f089d
 14 ac7b6101-6577-164e-bfb9-bcb1af152b05
 15 d37e6cc7-550e-496d-93a3-e8a0c3d7ab30
 16 69c06a2e-c64a-5cf1-b375-b111035d3f6f

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 6560755758161145. Exactly this sequence comes out of new Random(555).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 64 of Run 3 (seed 1,063,142,882): new Random(1063142882), Next(8,24) 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 2012-06-14 10:25–10:26).
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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