201207211254 wwr7v

explained decrypted filler

seed 330

Metadata

Post ID: wwr7v
Title: 201207211254 → 2012-07-21 12:54 on A858's clock
Posted (UTC): 2012-07-21 03:51:57
Timezone: UTC+9 · title 12:54 against posted 03:51 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,296 hex characters · 648 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9A858DE45F56D9BC9) = 0dcc4bd9e114ebc42078977dc9125404 (name+name)
GUIDs: 20
Filler GUID seed: new Random(330).Next(9) ✓ verified
Run: Run 16 (seed 39,036,328) (seed)
Draw: 29 · predicted N = 20 ✓
Machine boot: 2012-07-11 17:05–17:10 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 3 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: name+namerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,296 hex characters = 648 bytes = 81 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9A858DE45F56D9BC9 (name+name). Key = MD5(password) = 0dcc4bd9e114ebc42078977dc9125404, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 20 GUIDs as hex (shown below).

Decrypted: GUID list

  1 fc12ca8d-4407-1990-8657-3b6a29176074
  2 4827964c-d27a-5544-9ae0-3d034961f962
  3 29365d51-ae18-3b72-b34a-5001657cb1a6
  4 ecbde1e7-d3ce-8c03-a539-bf65d229045a
  5 4c9ec7a0-e95c-1dc7-8af1-debad175dd66
  6 58ac9de8-c725-8fc6-9f47-84d050aab9f9
  7 c48cb71d-a463-63d3-bc54-fbb5c951dff9
  8 7dd9eb3d-bd55-803b-92d8-00eaf780abb0
  9 ea3d08f5-e04a-7dbc-8128-de1cf373f41c
 10 db640f3c-226f-825c-a0f0-b723d0303476
 11 6aa499c6-cc54-3868-8db9-20d489b24bb3
 12 146d1685-f45e-0ac9-a15b-120ffe93a912
 13 2917a24a-9eb9-4998-9cf9-9990245705e2
 14 6259fda6-28e2-10a2-9f5c-47e9450359af
 15 ae49c562-078c-8279-b04c-e67c82477fe6
 16 64c5ccf8-58df-14e5-bc07-3ca8ba8b91ff
 17 da95726b-8f44-576a-8cf3-6064baf46c6e
 18 f87c8f75-45e4-5ace-bc2a-90551886310b
 19 9d2bdf39-aa1a-5e2e-8761-2d6e9d7675d6
 20 e9fb2c2c-0aa9-0b50-9592-7f4fb4c75b54

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 15381868783041815550. Exactly this sequence comes out of new Random(330).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 29 of Run 16 (seed 39,036,328): new Random(39036328), Next(8,64) per post. The RNG predicts N = 20; the post has N = 20 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-07-11 17:05–17:10).
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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