201209241209 10dhwl

explained decrypted filler

3DES(name+title) ECB, 16 GUIDs, seed 187

Metadata

Post ID: 10dhwl
Title: 201209241209 → 2012-09-24 12:09 on A858's clock
Posted (UTC): 2012-09-24 03:09:10
Timezone: UTC+9 · title 12:09 against posted 03:09 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,040 hex characters · 520 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201209241209) = 5797d390840ded27ca660ee647784f8e (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 16
Filler GUID seed: new Random(187).Next(9) ✓ verified
Run: Run 34 (seed 83,105,000) (seed)
Draw: 145 · predicted N = 16 ✓
Machine boot: 2012-09-22 10:23–10:24 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 1 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+titlerun: seed

From the post to its content

As posted (encrypted)

80A6371FBAFF107B 9A646650464F069F 267CD9164FDB88D1 07ACDBE9B58DD369 1B6326AAF65C3AFB 484D5E33B454DCE5 961E97FC7AE250D8 9984C5171D9AE57F EEBE7A6D577EF4D2 871A6B86AD11A36B 914701933E15967D 9A0961F98C143FBE E968A4B82509A70B 8A1F80C26D6EA91F 5968E06263BAAC9B 432C876F5FB10C8E 57D7C75F4FCB2792 C718E7E291E15400 480F90CF94C850AC 092E47F1F72ED70A 8F16B426AC1F65C5 06731EF0B90E896F 10198B3CA5DBC7B3 C56642FFE208CB74 D39CB8C1D9B3B6C9 F6D832523BE76347 B6AC35F58824BA82 780623B65BA6F6FB 2C6BE944B96BED94 A72D1C7ECAA2AE2F D23DA1735C9E508F 2193DB6CA9712B3D ECEBC3D5FEF386B4 4ABC29176341B793 1B6ECBED7FC5D758 C5DB6C1B70992A04 862CC2BDE2BD881B 3D431CE54354F1FF A638020041D54339 D349B011BE3B2E67 31FC7BBE8B594B94 1DBF6513FC75731E 6567008DC13A1F57 DA2580BD391C1DAC 0CD28D5CF5669CE4 AFA57561F9D26999 A2721431D5FE71B1 A43E94693C3B37FE 53A78BB219CFBEDB B48D07615B8A4AB7 8D48D1DA9951453F 9DDFBE3ABF7E3F9E 5CDF3C2E26C5C3EF 573AFA21D2D47FB6 DD9CE1653CB4886B D55C73422AC3D691 893DF002D1191169 1DD0A69A97D3F121 82A5E62904A85BD9 E2F730277AED7023 C2F71EC8073C827C 5ED3F79A1C80926F 28C9085E2E16014D 04005989B1C160F7 EDF6591D3885C633

Read the ciphertext. Strip whitespace: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209241209 (name+title). Key = MD5(password) = 5797d390840ded27ca660ee647784f8e, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 16 GUIDs as hex (shown below).

Decrypted: GUID list

  1 66826fac-7d38-37f2-a4ae-74f725d1a13d
  2 f937fc9e-5747-60a2-b23f-1507adac55a4
  3 9c2212c3-3ae2-4c9c-941d-67e4193fd4bd
  4 f07d4951-bb4b-4991-9023-7ff62859c077
  5 cec5475e-e91e-52b7-aaad-3889e11dcfad
  6 c2540e6a-0868-88e7-8f9b-ee19e876caab
  7 3881263e-6ff4-69bc-ae59-08c26fa07c98
  8 7f2a1187-a527-2107-95e1-bf0d7173d887
  9 e53f8306-feb9-1a10-9c58-502497097ece
 10 3ac67f20-b8cb-2140-8575-07b342f9cf34
 11 6569dd57-58b4-03e4-8106-5cef78b9fb17
 12 f06669a5-34d1-425c-b038-2b8e4b95b3a3
 13 3e21125d-0215-1686-b9c8-867bf7685c2e
 14 965815c4-e081-689e-82eb-ad0be6cfc1e4
 15 a2435f12-7c1b-78ee-aec8-b0368c7df015
 16 a62e7907-bf12-7436-bdd7-636fa72af7e9

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 3644586212041677. Exactly this sequence comes out of new Random(187).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 145 of Run 34 (seed 83,105,000): new Random(83105000), Next(8,64) per post. The RNG predicts N = 16; the post has N = 16 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:23–10:24).
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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