201206271229 vow8j

explained decrypted filler

seed 954

Metadata

Post ID: vow8j
Title: 201206271229 → 2012-06-27 12:29 on A858's clock
Posted (UTC): 2012-06-27 16:27:17
Timezone: UTC−4 · title 12:29 against posted 16:27 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,040 hex characters · 520 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
GUIDs: 16
Filler GUID seed: new Random(954).Next(9) ✓ verified
Run: Run 8 (seed 593,707,075) (seed)
Draw: 3 · predicted N = 16 ✓
Machine boot: F 2012-05-15 18:59–19:19 (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: namerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9 (name). Key = MD5(password) = 34a14a42e98ff96095af56604e290cae, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 16 GUIDs as hex (shown below).

Decrypted: GUID list

  1 75439feb-ef6f-1568-b527-fdd9d553661e
  2 94d6f224-6763-6ea9-8305-d78a97fb16e6
  3 91760805-ca0a-5df5-9b34-1383186f814f
  4 8eb68690-9dc5-1144-b406-b4c73edd86a3
  5 095f2c30-1fd0-8423-af07-1f3d2e9a8678
  6 9254dced-9117-2351-8313-af5f55ca8d55
  7 c4095fca-5994-3a95-b983-b114c8d18552
  8 8c19f222-72f0-0433-b426-c78049d25915
  9 d194232e-670b-008a-a5f3-5eecf5c1774a
 10 551326f7-206b-0ea1-b4fd-8d3036f68ff2
 11 b5b3bee7-54f1-17c7-b737-581af2c2527b
 12 8e9ba412-32ff-28e1-a1f9-257ba3921501
 13 6149b3cf-2bb3-4812-bd39-9c841452df83
 14 2e4eca4b-f4e8-7cc1-a581-f890ad0c66ff
 15 5bd64622-d39e-6b6f-b461-df9a7f706fad
 16 e8d740b1-7854-7769-a4ca-452d93c7b8ff

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 1651823000124767. Exactly this sequence comes out of new Random(954).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 3 of Run 8 (seed 593,707,075): new Random(593707075), Next(8,24) per post. The RNG predicts N = 16; the post has N = 16 ✓. The seed is the machine's uptime in ms when the app started (boot F 2012-05-15 18:59–19:19).
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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