201309211832 1mv2ig

explained decrypted filler

seed 611

Metadata

Post ID: 1mv2ig
Title: 201309211832 → 2013-09-21 18:32 on A858's clock
Posted (UTC): 2013-09-21 22:32:54
Timezone: UTC−4 · title 18:32 against posted 22:32 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(A858DE45F56D9BC9201309211832) = bf4cd531135c93b93f79c3522b903f55 (name+title)
GUIDs: 16
Filler GUID seed: new Random(611).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 122 · predicted N = 16 ✓
Machine boot: 2013-09-12 09:30–10:30 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 6 · 3
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

FCB6EE66414BC9E0 6076139DD6DB0247 2D3CA3BC6D88B3CB 524699D5E5ED8166 8BC5B8A7CB7AB075 EDE12C0BA4377AA2 31D2ACA5ADCE53BC CFE193AE5E444644 8EE0A2FC97D55321 C607D733CCDA9DB6 094D29EF80AF575D 7FF0AF332D9C342D 4175C896F5E8EA50 DA1AFF441AD8FF80 E378A940B431909A 677568BE5F0685E7 E952D448FE65E0F3 3B05931F9BF91956 B6C74F96F14E9740 7CED1B6BBEEC7272 B707D309BF523518 3F1AFF5E78A504A2 7D64B2D9D52D024D D568FEE358650C57 8315CB4A76C94727 E3DD0151751DC98D 2A520C9A7B5CF475 F0F762CA1A9AA569 3C48D123B7D9F596 9D8F507E4231B875 8C9FB53E9D53D94B D709946345F6A99F 38A99CC090A71181 5B0063CC9712F2EF 19F8733422820E76 DCFA72A12F540EB6 7588EFFF48188308 2FD70D9561835156 CD69A1BA46496C61 1E0B257E415B14F5 74B45C5FFCA16689 A108C4CE2C719024 80D40FC98B0EDF4D 6050A39412B77E27 85793C65E63A7632 A0699376306BC873 2ABB30610D75F121 0C29D8B2DB4F0918 3043D0EEE443C1B3 4DE2902F66192586 6FAB5DCDA07C8C10 15BB26F2050CF239 0A5506B4835C08B1 0FFD968333AD9255 6DC559747E6B4E82 30BC42B68CEF5F26 AEB4CC8E4A5CD593 1F8A3DAC50F05F34 EBF8BD87B73BBC7D 98528701B15E1231 BF87282F765D649D CE4209E3D0B9AF73 3F66CD3EE1F0F7E3 1EA3FA5129518199 5A6D48E7C01F6472

Read the ciphertext. Strip whitespace: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309211832 (name+title). Key = MD5(password) = bf4cd531135c93b93f79c3522b903f55, 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 19a55c8c-91ff-8417-8452-65aedd8af44f
  2 e56e6ea7-3063-000d-b22c-b251b74fb309
  3 c44d30b5-eca4-70b4-ad58-c20e15331d2c
  4 b91bdfc0-e5bd-8b1f-bf11-1ea806841240
  5 af702c04-ccb5-0b36-a21d-662e2fbb497b
  6 a98bb022-7a6e-4b2d-8d88-bf20c04838e1
  7 5347c696-a117-644e-a203-a4df333f7e06
  8 c687e2c8-5d46-888b-97f9-39addfca9d65
  9 569200aa-da09-583f-a89e-9724d7d4f86c
 10 c17e7a26-976b-5a9d-b1d8-b151a9e45b06
 11 fbf18688-ac2c-33ab-85dc-06940569c5d4
 12 c3a5a92c-cc4b-4021-a1bd-1539e2196393
 13 0f18c84a-2104-5a3b-97d0-7f25fc52e80b
 14 7402f888-94b1-31e7-87d5-a0b75f491016
 15 2777879f-61e2-5932-93fc-8c862a92fb2e
 16 37b97b69-7dab-5a5e-9d13-8bc48d6bc88c

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 8078046855345355. Exactly this sequence comes out of new Random(611).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 122 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) 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 2013-09-12 09:30–10:30).
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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