201206261139 vn4hf

explained decrypted filler

3DES(name) ECB, 18 GUIDs, seed 827

Metadata

Post ID: vn4hf
Title: 201206261139 → 2012-06-26 11:39 on A858's clock
Posted (UTC): 2012-06-26 18:37:31
Timezone: UTC−7 · title 11:39 against posted 18:37 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(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 18
Filler GUID seed: new Random(827).Next(9) ✓ verified
Run: Run 3 (seed 1,063,142,882) (seed)
Draw: 35 · predicted N = 18 ✓
Machine boot: 2012-06-14 10:25–10:26 (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: namerun: seed

From the post to its content

As posted (encrypted)

4200CA506353D19E 4DD4787F657A9160 F3CAE0E6A1E49592 65681392BD7CEC9D 7D8A351BE41A0BD8 5A0F7DF429B33ACF D1514BCF1ECCAD89 10EBCD886EDFAF29 5FA7D8C9C13DD73E BC0232DEDCEDD2E0 CEC900FF0737D0FE BDC7EAF94E4A2D46 28A84A672C445F60 EDCA4AE21A2585B5 3AE47F0BD313FFE8 5A11B0AD0A31E296 1EF882F1163D5890 C1211D5BC3360BB5 A85D884DC2F6E183 8C8ED0197B724FD9 C1BE14BD885605C0 0772AC16CAFD17B7 592338089112080B 5BDE0C9931CFDD75 4A2F25E373C3FAC0 F6A6B774B521E10B D76F3233E1B6EDD0 B72F696E7E566C5B 96570D4138AFBEC9 09ABDBC13208FD4A 796C88BCDD815596 391026525C77445B B28990D505F89373 9A2546523A451E58 BB9C896B1662C2D2 DBC6493D532604EE FE5D3E000F75ED3C 48DBF4B47DF0A483 1D6023063F1C9E87 C9E62E009270B6C0 B1A021F946E14441 262D7D6AF0135561 9DCFCC4E22F3CF7C 11F1F6AFB6EF15B9 80B499A54F44FB6A 0BF7C061CDC584E5 7EF11551D953E843 3F7D9A1205F71964 B47A1140C83BF22D E313B93CA0247493 25ACEBE58A414974 26B3A1D7684B7206 E9DE196637FED632 B20B9D9E5F07628A 33834534F7705751 FAE5DD7E81E0222F F9E9E0EB55D7D9AF DBA8591A86E7BFF4 4260FFF16EFBA93A 91690863A33D7D2F 6ED373457A8974EF 2785867A6FACAAFE DEDF7E3ACDE22ADB EBA7C2D48D442A0B 1E53F541313307F8 5EFBA8537D459DDA A556276884E84592 25B3BE9D1F4A3187 FDB58AD8B7E5F7DE 0A291B38F69A0548 6C9208BE84D0779C C79DFB8BAF3C9C76 5DACFFBA8FF64DBD

Read the ciphertext. Strip whitespace: 1,168 hex characters = 584 bytes = 73 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9 (name). Key = MD5(password) = 34a14a42e98ff96095af56604e290cae, 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 c5915603-6879-6a48-b51e-8593ab684d95
  2 fb6c288f-e1e9-41a1-afb3-13bb73f4feea
  3 7566f9d5-fa7a-7016-8e46-94ed04dd92c8
  4 84c20b15-93ec-0d8c-a5a4-30e8759e7ead
  5 74a1f080-01de-5092-9c1e-0f7325846a81
  6 feb452b8-0a83-2f31-9eb1-c0cf2f603c33
  7 35bae150-ff02-41ee-b6b6-2c0cfe64ffff
  8 1f72b5d1-cbba-3aac-84d7-e5929b07bb6f
  9 d2fe6ebc-2e42-285b-b7ef-bae2b9dd8109
 10 d749e682-3587-24dd-b065-a728c430b213
 11 2ce96a57-f772-5b6c-b960-38622166be31
 12 55f4a17a-5ad7-1151-a448-a67d0db4cb57
 13 c767f3fc-8abe-12f2-a9d8-0858e8618a67
 14 bbcc2fbe-97b8-6a28-8ac8-c3fcbf26ec89
 15 418d4820-f0d2-7c53-8f3b-30a43fbc667f
 16 6bd5a3d0-e119-4b2b-9ee5-5d48623b108e
 17 a7bc2c68-6b92-4c0d-9501-2bbc01e3b477
 18 92570e0c-1bd3-63a6-b8aa-a39d3a8c34ed

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 647052432251167446. Exactly this sequence comes out of new Random(827).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 35 of Run 3 (seed 1,063,142,882): new Random(1063142882), Next(8,24) 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 2012-06-14 10:25–10:26).
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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