201212031847 1489t7

explained decrypted filler

seed 646

Metadata

Post ID: 1489t7
Title: 201212031847 → 2012-12-03 18:47 on A858's clock
Posted (UTC): 2012-12-03 23:47:06
Timezone: UTC−5 · title 18:47 against posted 23:47 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,232 hex characters · 616 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201212031847) = a8ba0d33bf6bf710f14af7ba25fcff9d (name+title)
GUIDs: 19
Filler GUID seed: new Random(646).Next(9) ✓ verified
Run: Run 39 (seed 1,106,402,812) (seed)
Draw: 8 · predicted N = 19 ✓
Machine boot: 2012-11-20 22:02–00:02 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 1 · 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: 1,232 hex characters = 616 bytes = 77 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201212031847 (name+title). Key = MD5(password) = a8ba0d33bf6bf710f14af7ba25fcff9d, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 19 GUIDs as hex (shown below).

Decrypted: GUID list

  1 b83c935a-f329-157c-ac28-67d3191ad7b3
  2 f5f8f392-e658-33d2-a64c-549383b54ad9
  3 06a45e84-5044-22b1-adb6-f3df01fa522c
  4 1aa8ac8b-2440-36c4-a84d-633788861d81
  5 bfb46670-9432-746d-8498-489f05a1d160
  6 87479dec-73ad-0890-8eb1-f9f8d956d895
  7 3f37af17-9071-3a0b-add8-5118654346cd
  8 dded6cc5-3b9a-45fa-8423-49805bb6c525
  9 1117ecfc-4a0f-8db6-98c9-0fc462afd01b
 10 d8c3c025-fe39-409a-b622-69e7eff342bb
 11 76aec910-8bd7-103b-927b-c98edb4338df
 12 74563cf0-20cd-72fa-b5bb-c77d4747f670
 13 7d4c5e9c-ca81-60b7-91fc-9527ff5ac6fc
 14 592361a2-3b79-4c20-9635-c6088a053c31
 15 2d22c4ca-86aa-1d09-bfa6-ad7cb280f98a
 16 a5b46018-92b9-4c6d-a66c-cbe3e2371604
 17 e172a895-06ed-3e65-96de-e0300506a819
 18 6d3dc0f3-fbf9-4388-a872-16695cc776d6
 19 6222c2d6-f795-1747-923c-a3bced5ed9d2

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 1323703484176414341. Exactly this sequence comes out of new Random(646).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 8 of Run 39 (seed 1,106,402,812): new Random(1106402812), Next(8,64) per post. The RNG predicts N = 19; the post has N = 19 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-11-20 22:02–00:02).
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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