201206270845 vnr8f

explained decrypted filler

3DES(name) ECB, 16 GUIDs, seed 255

Metadata

Post ID: vnr8f
Title: 201206270845 → 2012-06-27 08:45 on A858's clock
Posted (UTC): 2012-06-27 00:43:48
Timezone: UTC+8 · title 08:45 against posted 00:43 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(255).Next(9) ✓ verified
Run: Run 6 (seed 652,173,660) (seed)
Draw: 14 · predicted N = 16 ✓
Machine boot: F 2012-05-15 19:06–19:16 (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 a8603b0c-2b90-8da7-931c-04b797898745
  2 c83f9c0b-c4e6-557f-96a5-44f23fbb8769
  3 43a51986-3d37-0284-990c-cded6998769e
  4 49e150a7-8bdd-80b6-9db8-feac207c052e
  5 740f1fe6-62c7-3173-b07f-804649efb629
  6 2a33f0be-a8ce-3969-bda5-20ba53e88dda
  7 9eb07750-9c58-15b9-8f7c-32ff6643bb2e
  8 1114ee36-4395-308c-a9a6-8769f243827a
  9 86469bb8-85aa-42e2-aaf8-0e370dd60b3d
 10 89453a68-fe12-21ee-b726-4e62a1021bb5
 11 e0bd3eb7-1484-1611-a5fe-d77a9a9b0fa8
 12 69b4954d-4764-4048-8ee6-359a1e3ade7f
 13 70bd1895-e438-8caf-8ef1-f4be52df75aa
 14 70f823a9-16cd-1919-b553-0794707bf3f8
 15 96b0440f-b31a-4f1a-abc7-3c37c0622f87
 16 34a0d7c4-b73a-2e98-b120-72e021b59a17

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 8508331342148142. Exactly this sequence comes out of new Random(255).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 14 of Run 6 (seed 652,173,660): new Random(652173660), 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 F 2012-05-15 19:06–19:16).
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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