201206261123 vn3fk

explained decrypted filler

3DES(name) ECB, 14 GUIDs, seed 75

Metadata

Post ID: vn3fk
Title: 201206261123 → 2012-06-26 11:23 on A858's clock
Posted (UTC): 2012-06-26 18:22:12
Timezone: UTC−7 · title 11:23 against posted 18:22 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(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 14
Filler GUID seed: new Random(75).Next(9) ✓ verified
Run: Run 3 (seed 1,063,142,882) (seed)
Draw: 26 · predicted N = 14 ✓
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: 912 hex characters = 456 bytes = 57 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 14 GUIDs as hex (shown below).

Decrypted: GUID list

  1 182b581a-37d2-869a-9838-fb3fe5af88f0
  2 adbda018-e7ac-78f7-b22d-6840a67cb410
  3 7eed8e74-f348-166d-b206-ebb85b750dce
  4 2a6eacc2-1d2c-5482-86c0-87a53c82fbdf
  5 5ff1df91-500b-0819-9528-80407580dd52
  6 253d3c10-687d-0b7f-9a30-1ca5052961b8
  7 a45a7869-9f9b-420e-a5d1-6f4d6e9ae153
  8 59466bca-417b-053d-9393-5be826d6c4ef
  9 bb6d817d-abc7-2c60-b54a-3389a57cf652
 10 5ed9ab48-3c82-8ffb-a201-949ce073bba4
 11 f14776cd-078c-418e-ba14-df60ed8a5db0
 12 03e93117-7152-0a83-9b5f-2d2f9e016e53
 13 1118cad4-c7fc-1f77-b5a6-739e89eab33e
 14 d7b342e3-749d-4415-9eb9-178e7d2ce8bb

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 87150040284014. Exactly this sequence comes out of new Random(75).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 26 of Run 3 (seed 1,063,142,882): new Random(1063142882), Next(8,24) 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 2012-06-14 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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