201210020540 10t5a0

explained decrypted filler

3DES(name+title) ECB, 8 GUIDs, seed 544

Metadata

Post ID: 10t5a0
Title: 201210020540 → 2012-10-02 05:40 on A858's clock
Posted (UTC): 2012-10-02 09:40:05
Timezone: UTC−4 · title 05:40 against posted 09:40 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(A858DE45F56D9BC9201210020540) = d1cf3b2fa5ad8cbef93f0749f0e66710 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 8
Filler GUID seed: new Random(544).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 5 · 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 = A858DE45F56D9BC9201210020540 (name+title). Key = MD5(password) = d1cf3b2fa5ad8cbef93f0749f0e66710, 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 fa74a359-01c5-810e-9391-7b28a6109de9
  2 e102b9cf-1d7a-3657-99fa-afeb1c8cec66
  3 ee7211e3-fad6-059b-b6c4-4b2a5489aa91
  4 8a305e18-7867-6cf3-ac12-70f02df5fe06
  5 f575b5d9-d278-7bf1-add8-3ec66154ba48
  6 31b53501-ad4d-8bea-bee4-41d1c4336b78
  7 ed3e1d07-20f8-5776-89f8-a126acb9b1a5
  8 95735d9b-5586-36c3-9a38-281e60c77ddd

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 83067853. Exactly this sequence comes out of new Random(544).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 5 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

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