201207071743 w707g

explained decrypted filler

seed 689

Metadata

Post ID: w707g
Title: 201207071743 → 2012-07-07 17:43 on A858's clock
Posted (UTC): 2012-07-07 21:41:22
Timezone: UTC−4 · title 17:43 against posted 21:41 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,360 hex characters · 680 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9A858DE45F56D9BC9) = 0dcc4bd9e114ebc42078977dc9125404 (name+name)
GUIDs: 21
Filler GUID seed: new Random(689).Next(9) ✓ verified
Run: Run 14 (seed 205,976,312) (seed)
Draw: 0 · predicted N = 21 ✓
Machine boot: 2012-07-05 08:28–12:28 (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: 1,360 hex characters = 680 bytes = 85 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 21 GUIDs as hex (shown below).

Decrypted: GUID list

  1 3f1e3178-b4be-6ad2-95f4-75dd6c283157
  2 8330f68c-416a-8895-bb8e-d48cd589d1b1
  3 9d35a1c7-e1af-3af7-893d-5790ec67d416
  4 9429ebd4-debc-53ad-9b1c-d90c2c49380d
  5 7958dc24-0e88-2fd6-a218-883d62c808a2
  6 d935c2ba-4cca-6c3e-8110-971f89ccf14c
  7 c6c31280-08bb-5993-b1ca-6f2ac602dd5c
  8 811bf90a-46d6-0402-8dde-8556166e6683
  9 b798c7b1-d72b-1d16-b62e-14bbfe63a2e4
 10 e570c049-3994-3f30-901c-f24bfdd62bc8
 11 0457a561-f820-874e-9e2b-e869c643c554
 12 36189235-670a-3e83-af64-2641f64da1cd
 13 544b9ff9-3b96-29f1-b2ed-a546bd98c2d4
 14 4ffb3786-4e67-81d5-8f57-64245e6215ec
 15 cac7fcfc-b402-2218-a8ee-25c724e80361
 16 20af02fa-1c29-2fef-87df-8078cdab88f3
 17 44b32ced-b506-40a8-9df6-c9568ec0484a
 18 7a95c671-9c3e-1ee0-afcc-a9579b8d4b6e
 19 b74bdec8-2f17-2363-816a-cd24a57abf87
 20 c0e3e26d-b191-09a4-9af7-2699d9379698
 21 65c13d57-77f5-34d0-b1b6-c39a5070591a

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 683526501383282241203. Exactly this sequence comes out of new Random(689).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 0 of Run 14 (seed 205,976,312): new Random(205976312), Next(8,64) per post. The RNG predicts N = 21; the post has N = 21 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-07-05 08:28–12:28).
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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