201210160559 11j4y6

explained decrypted filler

seed 822

Metadata

Post ID: 11j4y6
Title: 201210160559 → 2012-10-16 05:59 on A858's clock
Posted (UTC): 2012-10-15 21:00:00
Timezone: UTC+9 · title 05:59 against posted 21:00 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 528 hex characters · 264 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210160559) = 42e2ed5544bb9b110902a41445b3a503 (name+title)
GUIDs: 8
Filler GUID seed: new Random(822).Next(9) ✓ verified
Run: Run 37 (seed 425,468,968) (seed)
Draw: 0 · predicted N = 8 ✓
Machine boot: 2012-10-10 14:48–22:48 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 26 · 3
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: 528 hex characters = 264 bytes = 33 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210160559 (name+title). Key = MD5(password) = 42e2ed5544bb9b110902a41445b3a503, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 8 GUIDs as hex (shown below).

Decrypted: GUID list

  1 448b5f64-6801-182b-bfaf-5eeef36c20b1
  2 a9c276c3-21d4-0888-89f1-caf050a8e894
  3 62f9331b-46cf-36de-8314-d926e03ae34a
  4 026d4660-c5f2-0a6c-ad13-c764661a0a2c
  5 eb6d0536-e91c-2b18-85d6-6af2a9b48673
  6 05d889d9-5f12-85f9-b047-cf1a7e1a0b38
  7 e9073a34-fb15-1dc3-8890-be9215e4eac2
  8 3f9d7cd9-562f-7689-8d8f-affc33bd7152

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 10302817. Exactly this sequence comes out of new Random(822).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 0 of Run 37 (seed 425,468,968): new Random(425468968), Next(8,64) per post. The RNG predicts N = 8; the post has N = 8 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-10-10 14:48–22:48).
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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