201211081755 12umxq

explained decrypted filler

seed 604

Metadata

Post ID: 12umxq
Title: 201211081755 → 2012-11-08 17:55 on A858's clock
Posted (UTC): 2012-11-08 09:55:19
Timezone: UTC+8 · title 17:55 against posted 09:55 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(A858DE45F56D9BC9201211081755) = bc00b6abdd0568160d667c69ec6778df (name+title)
GUIDs: 18
Filler GUID seed: new Random(604).Next(9) ✓ verified
Run: Run 38 (seed 1,045,884,937) (seed)
Draw: 105 · predicted N = 18 ✓
Machine boot: 2012-10-11 03:41–03:51 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 7 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

9445E24E79F07944 A1592AD7F8D77825 6E3D6DCC0998E6D2 2E25C213945AB95E 474AA78E4493EE44 EAF20EAA637ECCC6 45949EDF07D00EAF 10A3D1BCEFA40002 28C0B25B33D96E55 775C556063FD2D33 F3E97495142977F3 A184272F2AC08ABC 1636D500860C7026 F9578322FF26A33F EEC59466541A2CF0 7A05B9F3CA53EC04 DA9082C2C5655AE9 B981E3ED1F288F63 9BE6E69A52202592 8C7B659D48834420 4816B216353B72A0 A353D12172F295BA D6A5CD4A55B4EA8B EF151B2E8127AEE4 262962928B593B83 15833D29EFF9BF6B 419E942A3F359EC5 037DE730FD1198ED 7DCD13324EBB2CF5 53C8D113835495F3 5ADA3734BB1B1F96 959535ED8E2DAF3E FA233E58CFD2B30C 25DAA95DDE66AC92 DBB4DBD55C77E104 CC473E7CDB99DDF6 54C622D5AB15DE30 696DE439813079D5 5179501B9192B0E6 7902FFC2BA5585F5 B1FBDB98239731F8 88697475A07946A5 1B634DE61B3AA38A 19CC370867AC895E E1C1C1ECA88051F7 03BBAB82DA07FDE3 FF0BD857BEEBB606 C2AD6881AC0790D8 46208B9F8B396991 51DEF3E34A953B01 96093A10174CFDCE DE4990828CFD8B20 5753DDF49675E59B 5AF96418816B0817 58FF36DBCB7DEEBE ED983A4D133613AE B9997851B1CC19DA 2A3895C1E068597C 1DAA904DF623F526 62059F41578F5B14 17B0A545D35B54F0 6E659321091AC2C3 3FA9CB1B961B7527 9F5DD4327BE31298 5117B032C2BE41A7 363AA504FA47BF4A F6303FEF22CB6BC9 75BCB3E833285E5D 77C982DEE51B387B 3C26CD685BA30C23 03D793432422D467 C63A84AF12810DE6 1EF5C28FF9BE7273

Read the ciphertext. Strip whitespace: 1,168 hex characters = 584 bytes = 73 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201211081755 (name+title). Key = MD5(password) = bc00b6abdd0568160d667c69ec6778df, 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 1a81a647-3c60-2846-9299-9c9744deec67
  2 02cddb6a-369b-0b1e-90db-e2c333686215
  3 ade92a5f-6aa6-8c65-8d3a-1542117c8003
  4 03e72206-52b3-49e1-8973-0bc7c70c8612
  5 b53579da-7c11-89b5-8150-c50e0c5881f2
  6 e09865d2-c85c-3f7f-8306-8e43c8c5f5e4
  7 72388fcd-b5c3-42fa-a3ce-0bc2e6a946c6
  8 9bc906a2-c829-4ae3-ab0d-29c5e76ef058
  9 1ee48364-0cf7-6237-a800-97371d5465d5
 10 96aa51fd-1c51-86fb-b29d-6598212c900d
 11 5057592c-1175-2f43-b111-68f2bb3d63f3
 12 35712201-ad79-031c-bb27-2efabcfbb78a
 13 8caeb29b-edd8-7db8-a392-963f0811f198
 14 0541563b-2661-6c74-a5f3-912b63fdc043
 15 c8f4412a-1178-6601-a367-8702567807d4
 16 e5492343-6d44-270f-8678-fbfb0396fcfc
 17 8b30c619-cfba-658f-8cbc-efc4420c369c
 18 7fc59309-296e-44c3-b508-81915bd08e28

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 208483446820766264. Exactly this sequence comes out of new Random(604).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 105 of Run 38 (seed 1,045,884,937): new Random(1045884937), 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 2012-10-11 03:41–03:51).
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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