201210021220 10tm6v

explained decrypted filler

3DES(name+title) ECB, 11 GUIDs, seed 12

Metadata

Post ID: 10tm6v
Title: 201210021220 → 2012-10-02 12:20 on A858's clock
Posted (UTC): 2012-10-02 16:20:20
Timezone: UTC−4 · title 12:20 against posted 16:20 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 720 hex characters · 360 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210021220) = 416d7cfb9395e9a138d8744aa267a075 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 11
Filler GUID seed: new Random(12).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 25 · predicted N = 11 ✓
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: 720 hex characters = 360 bytes = 45 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210021220 (name+title). Key = MD5(password) = 416d7cfb9395e9a138d8744aa267a075, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 11 GUIDs as hex (shown below).

Decrypted: GUID list

  1 b8a5379c-fb63-87bb-a017-ae8b453a9c38
  2 da6b83db-91fd-3f55-84db-5be8a302b7c0
  3 9b08096f-f4da-1f3c-a8dd-ae63f8d42cba
  4 8a386ae4-3913-1dc2-af49-fc3b9be88a85
  5 4074e42b-11e3-5987-913b-628005b5ae1d
  6 353a1710-f0dd-01de-9473-1472d2ea8f32
  7 5931a4b9-4a5a-264e-81ba-1650239158c9
  8 d68e0eb3-2551-4615-bd8a-59b9ee2363e3
  9 e73e0fc2-dc66-421a-9d41-f8f21c28212e
 10 cd0abac8-8b3c-6165-a0a1-719adc8c6e51
 11 c78b5086-b856-1d3c-8e4f-a4ecf2ac32e9

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 83115024461. Exactly this sequence comes out of new Random(12).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 25 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 11; the post has N = 11 ✓. 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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