201210040441 10xelh

explained decrypted filler

3DES(name+title) ECB, 8 GUIDs, seed 968

Metadata

Post ID: 10xelh
Title: 201210040441 → 2012-10-04 04:41 on A858's clock
Posted (UTC): 2012-10-04 08:42:00
Timezone: UTC−4 · title 04:41 against posted 08:42 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(A858DE45F56D9BC9201210040441) = 5844283264b5da7c78ba4fbcff919fa6 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 8
Filler GUID seed: new Random(968).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 146 · predicted N = 8 ✓
Machine boot: 2012-09-22 10:16–10:36 (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: 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 = A858DE45F56D9BC9201210040441 (name+title). Key = MD5(password) = 5844283264b5da7c78ba4fbcff919fa6, 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 21d2a226-0e7d-3df9-ab1b-fe4fd837f831
  2 fad059b4-6b50-7ac1-b46f-d501c85bcfe3
  3 6300efc3-9f5a-3361-ab0c-d5dc5c0ab105
  4 07968e5e-7400-19d3-a929-9043b45a1987
  5 0a9c5366-b5ab-2987-bad6-6991c6308e57
  6 b7e93849-b2de-4bfa-950d-f6e56da940e0
  7 127650f8-f40c-5e75-9e5a-942737d7e84a
  8 be1fa44d-8406-00a7-ac9f-f4bd21adca5f

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 37312450. Exactly this sequence comes out of new Random(968).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 146 of Run 35 (seed 854,622,578): new Random(854622578), 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 2012-09-22 10:16–10:36).
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

Related