201212040547 1499bw

explained decrypted filler

seed 514

Metadata

Post ID: 1499bw
Title: 201212040547 → 2012-12-04 05:47 on A858's clock
Posted (UTC): 2012-12-04 10:47:19
Timezone: UTC−5 · title 05:47 against posted 10:47 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 592 hex characters · 296 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201212040547) = ad4b22e5ffda02dbb9e2f06599bd7475 (name+title)
GUIDs: 9
Filler GUID seed: new Random(514).Next(9) ✓ verified
Run: Run 39 (seed 1,106,402,812) (seed)
Draw: 28 · predicted N = 9 ✓
Machine boot: 2012-11-20 22:02–00:02 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 0 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 592 hex characters = 296 bytes = 37 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201212040547 (name+title). Key = MD5(password) = ad4b22e5ffda02dbb9e2f06599bd7475, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 9 GUIDs as hex (shown below).

Decrypted: GUID list

  1 9987be97-8a08-24fa-86a8-af3609761555
  2 95df5862-f254-5c82-959d-37a09f7b1168
  3 430e2872-7244-0bb4-b2b0-7c394f7f0214
  4 87c413fd-2366-24fd-bb97-b0fb2d0d9ed3
  5 a2db8c2a-39a9-2817-ab33-78207e8171df
  6 058edd0b-ead6-6014-beff-5cf1932acb09
  7 2be380a4-6f51-1df6-b194-4a37a823e3f8
  8 24ede5b9-5f42-252b-b2df-988e168a0a94
  9 d115065f-b6d6-5547-b8ff-4dec696c94cc

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 250226125. Exactly this sequence comes out of new Random(514).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 28 of Run 39 (seed 1,106,402,812): new Random(1106402812), Next(8,64) per post. The RNG predicts N = 9; the post has N = 9 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-11-20 22:02–00:02).
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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