201210200600 11rn82

explained decrypted filler

seed 595

Metadata

Post ID: 11rn82
Title: 201210200600 → 2012-10-20 06:00 on A858's clock
Posted (UTC): 2012-10-19 21:00:05
Timezone: UTC+9 · title 06:00 against posted 21:00 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,168 hex characters · 584 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210200600) = ac9e39c18b1f9acaaf1c00486957ae69 (name+title)
GUIDs: 18
Filler GUID seed: new Random(595).Next(9) ✓ verified
Run: Run 37 (seed 425,468,968) (seed)
Draw: 12 · predicted N = 18 ✓
Machine boot: 2012-10-10 14:48–22:48 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 8 · 3
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: 1,168 hex characters = 584 bytes = 73 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210200600 (name+title). Key = MD5(password) = ac9e39c18b1f9acaaf1c00486957ae69, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 18 GUIDs as hex (shown below).

Decrypted: GUID list

  1 8a6934ba-3f34-5778-bdd9-e2cdd27a91fe
  2 9690b6d1-d2f6-3b76-8ef8-e38cbf53ebbe
  3 3a2910de-54cd-5aeb-9375-35aa62742363
  4 5c405e70-8ca0-5e17-9848-a99cfb9e52b0
  5 0c8d60ea-cc51-72e0-b18c-bff559238f77
  6 f14a7e69-d4fa-45f0-89e2-43100009d53d
  7 aa9207e7-c211-4d94-bb86-1748a4c03acb
  8 3d88f937-2fd4-8f5f-855b-2e61fa34cf4c
  9 a94740c0-20f9-5afa-9c06-17188582841d
 10 5de0ab8c-c5c5-6620-af91-83467ab8a6d8
 11 428790b7-f5d8-5bf0-a94f-ed0baa22daa8
 12 077a075a-089f-8b72-bf96-5009f7bc0d6c
 13 caed1570-d21c-55bf-b889-48401a528334
 14 6936bfba-897a-0559-982e-81e64526fa3f
 15 bdef539f-6233-4b38-9de6-3a1b865dedd3
 16 ae80a7d1-f650-5098-bc33-6f6b61a99126
 17 9a38c367-ab0e-84a2-975e-9366fc0b68e9
 18 5fcf724b-4be3-8fa1-92a9-ad5d48b6d431

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 535574485658504588. Exactly this sequence comes out of new Random(595).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 12 of Run 37 (seed 425,468,968): new Random(425468968), Next(8,64) per post. The RNG predicts N = 18; the post has N = 18 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-10-10 14:48–22:48).
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

Related