201210070124 112sex

explained decrypted filler

3DES(name+title) ECB, 14 GUIDs, seed 855

Metadata

Post ID: 112sex
Title: 201210070124 → 2012-10-07 01:24 on A858's clock
Posted (UTC): 2012-10-07 05:24:48
Timezone: UTC−4 · title 01:24 against posted 05:24 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 912 hex characters · 456 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210070124) = 55534484a7d2f35cb2f38b4113274bd1 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 14
Filler GUID seed: new Random(855).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 352 · predicted N = 14 ✓
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: 8 · 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: 912 hex characters = 456 bytes = 57 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210070124 (name+title). Key = MD5(password) = 55534484a7d2f35cb2f38b4113274bd1, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 14 GUIDs as hex (shown below).

Decrypted: GUID list

  1 fcf94fc5-d5c2-3882-9432-9c4bee019617
  2 87e547ab-e781-6266-bdc5-1d02f78a11f3
  3 6f73b49e-19a6-3d8b-a7b6-74124d8c497b
  4 9bb79178-1abe-0ea6-b107-73785e6863f4
  5 e42a2967-67d2-2e90-84a3-dc5dee4e5793
  6 3b6f040b-ec12-695b-98c1-2cd9d18cf162
  7 a3c88aa9-4b84-811b-a63c-4636667e69c9
  8 bb4ba73b-7e25-3a35-8aeb-0f147c841955
  9 a3273c8a-4635-6ffc-ac91-b58b1fdada9a
 10 a59b86eb-e625-5218-ba41-b6e02344d534
 11 6198d5c0-24ed-12ce-86a8-9cc3d7d27fb6
 12 9a266f3b-c1c5-87f2-aa54-a486a9ef32e7
 13 6c58634d-6564-3d84-857d-f9a38596de70
 14 d0659c06-2ca8-233c-92eb-577c747adc4c

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 36302683651832. Exactly this sequence comes out of new Random(855).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 352 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 14; the post has N = 14 ✓. 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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