201210052043 110rzq

explained decrypted filler

seed 525

Metadata

Post ID: 110rzq
Title: 201210052043 → 2012-10-05 20:43 on A858's clock
Posted (UTC): 2012-10-06 00:43:40
Timezone: UTC−4 · title 20:43 against posted 00:43 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 848 hex characters · 424 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210052043) = 07bb999746dd4c7a593c8147fe7b7da5 (name+title)
GUIDs: 13
Filler GUID seed: new Random(525).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 266 · predicted N = 13 ✓
Machine boot: 2012-09-22 10:16–10:36 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 2 · 0
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: 848 hex characters = 424 bytes = 53 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210052043 (name+title). Key = MD5(password) = 07bb999746dd4c7a593c8147fe7b7da5, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 13 GUIDs as hex (shown below).

Decrypted: GUID list

  1 d8ea7215-0ee4-87c6-9cd4-e5eef20e165d
  2 becd401b-0df2-743a-bad6-f5efbf69592a
  3 1a6b41c1-277b-6640-863f-9c0bda881165
  4 6894d64d-a284-5b1f-8fc2-d5301d0a7202
  5 4b7e1560-11d8-209d-ba62-87590177b9d2
  6 bf93d2fe-d80b-34a3-8cf2-149c375f57cf
  7 98378a7e-444e-185a-8edc-8d2dd29ca520
  8 cf007d14-b5a3-7e33-8688-c9eb23dda3c5
  9 75691a15-476a-87f6-a39f-bdf4954456c3
 10 469d17b1-571d-71ad-9762-bfd4c18d8b2b
 11 9a3107fd-6184-03f3-9488-8dcb06653d14
 12 f12490cb-7290-3f5a-9cf6-eca8293f5dbc
 13 3e98c038-0089-4a58-8de8-5b971b13de9c

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 8765231787034. Exactly this sequence comes out of new Random(525).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 266 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 13; the post has N = 13 ✓. 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