201210072125 11456y

explained decrypted filler

seed 82

Metadata

Post ID: 11456y
Title: 201210072125 → 2012-10-07 21:25 on A858's clock
Posted (UTC): 2012-10-08 01:25:34
Timezone: UTC−4 · title 21:25 against posted 01:25 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 592 hex characters · 296 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210072125) = d37f310b49268638b673c0e7e283f690 (name+title)
GUIDs: 9
Filler GUID seed: new Random(82).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 412 · predicted N = 9 ✓
Machine boot: 2012-09-22 10:16–10:36 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 2 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

625B02261097158F C47F03861D164A58 95A135A6309D3424 60F9B36907D92041 5D24180718C8F08C 7BFBD8E54A8A2391 D3EF63A7B2BF8245 761FA7489B9D4CFC 4A7E56536B03E725 63F9DFA4A4CE1E46 1AD1C21A00B9D9DC 2EDF1BF6C95E1534 888F0DAE596B99E4 95C09719F723B069 4A79C96DDC77102F 77CA2F317AD66F35 1F580548CCE2E5CC D57B8FABE2C0835A AB86BACBC342D9FD 088835BE53128697 171F58012046EFCB 5CFFD3633BA1DAAD F71880071986CA64 792ADC1CCA2812B5 C7F4AA27B139D37B 2A4BC147F039A4FB DD944FBB5CD61D08 001FBFDC80BAE0D4 0EDABBD94C87FBA3 99899A98F5F7C955 A7EDA3B998C02F60 A48ED6C9F6D470D6 957C3D8E39099834 6B1E265606AFAB12 FE5C526D7EF3D21F F509054B0B2FDD0A 6656CC12C646D4D7

Read the ciphertext. Strip whitespace: 592 hex characters = 296 bytes = 37 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210072125 (name+title). Key = MD5(password) = d37f310b49268638b673c0e7e283f690, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 9 GUIDs as hex (shown below).

Decrypted: GUID list

  1 50c81ea5-206b-5b23-aff6-08e09b8e9e56
  2 e870d109-d188-7edd-ad44-5a6815a9236f
  3 cf29bbed-bb9e-0896-acc1-4d617c148dd5
  4 f9a9b966-5332-0d09-8f9d-50c956d6e57d
  5 bcaffacd-2141-250e-ba57-fbc1ce26e89d
  6 78737519-9355-1d8c-b757-fcb4654e5dc7
  7 5925a654-0dc8-504a-a542-c204280c7081
  8 3d0fc0cc-65e4-56b1-a66b-d38c533341b1
  9 d87f38ca-bc3c-1232-8fae-abe889e7980a

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 570021551. Exactly this sequence comes out of new Random(82).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 412 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 9; the post has N = 9 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:16–10:36).
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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