201208112330 y2ty9

explained decrypted filler

seed 219

Metadata

Post ID: y2ty9
Title: 201208112330 → 2012-08-11 23:30 on A858's clock
Posted (UTC): 2012-08-12 03:27:44
Timezone: UTC−4 · title 23:30 against posted 03:27 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,296 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(219).Next(9) ✓ verified
Run: Run 22 (seed 528,385,484) (seed)
Draw: 65 · predicted N = 20 ✓
Machine boot: 2012-07-27 19:02–19:13 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 2 · 1
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 7f19fba4-110b-107d-9e99-b5eb6584b7b8
  2 59218783-8d96-0d8b-b4c9-9b96cedaaf8d
  3 6ca95c55-eb5e-778f-908e-c5ea2158b89b
  4 3fded652-8ee5-229c-88f1-71172de5af66
  5 1a81630e-b325-0609-8101-9c1b7b12365c
  6 66486654-700e-8bbb-b1a6-3581ec52abc4
  7 82eb0156-47fd-0542-b81e-a011f88a567a
  8 4746394c-212b-2f5d-b509-8c1014571979
  9 898160ae-ea02-001e-899b-c0878b705aa9
 10 9efd44f8-f1e9-02bb-9f47-642acec6c271
 11 b440c62c-40a2-5106-8640-09839428486a
 12 84c64ae9-2048-31b4-b673-7b8be3c24d0c
 13 61463343-dd28-1d25-8c7a-afc0f51fcd57
 14 5a9d2648-4a1b-3b0e-ae55-33d9d3a6007f
 15 a596a213-2f09-2622-9602-9c2ff2b4641a
 16 6c8c905f-c11a-7856-be54-1b7cb43c3590
 17 5cdcf23e-a360-8aae-a8c2-f8cf39a24087
 18 01f8f510-faa7-6240-8032-74184acc709e
 19 e9789933-9961-5a85-8c47-acb7921aa84b
 20 08187048-4357-1296-8314-a43068860f64

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 10720802005313278651. Exactly this sequence comes out of new Random(219).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 65 of Run 22 (seed 528,385,484): new Random(528385484), 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 2012-07-27 19:02–19:13).
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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