201208131910 y4znh

explained decrypted filler

3DES(name+name) ECB, 29 GUIDs, seed 670

Metadata

Post ID: y4znh
Title: 201208131910 → 2012-08-13 19:10 on A858's clock
Posted (UTC): 2012-08-13 10:07:30
Timezone: UTC+9 · title 19:10 against posted 10:07 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,872 hex characters · 936 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9A858DE45F56D9BC9) = 0dcc4bd9e114ebc42078977dc9125404 (name+name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 29
Filler GUID seed: new Random(670).Next(9) ✓ verified
Run: Run 22 (seed 528,385,484) (seed)
Draw: 82 · predicted N = 29 ✓
Machine boot: 2012-07-27 19:02–19:13 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 7 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+namerun: seed

From the post to its content

As posted (encrypted)

F183F7A03620657B 46C7AEEA3AF7BFC8 D552161BD7DDF7A8 C9EBB3A2CF456EA2 C93239AAEC310B6A 72B4E1AD211C77FF CC0041C1C8CC917E EE3B4E527BEC1FDB C06F068B517E9EB4 76614DB7CC29175F 1D4951CF47C9EDDC 7CB1AD152DD13D71 ED00826C11995313 B6D6DF2B38417020 1A2B4067E1E116DD 3D4C686CC92B9518 11D66C2B2CB41097 BF7F8122C223A093 0FB2D1A1A6E19F4A C8FCA51BF96AC2B5 1A8450924C858914 2C4686FD7ECE1D07 F2B02A2B5CABC4AF 2FC0E7D2913D187E 27B2E281470B33F9 6FB07A8B5291D046 97325D5279BDF292 FAC5DE9F5A7DCCE7 B8F0DD0D56D6ECEF 3CD011086A30509D 6C4A62EF4031E150 782262FFA6FFA870 D7BBEE01E2C565D5 4E0C563B811A7344 3F1C4447B702D116 DBE22E6573EFA74A C7BED70967855FA3 F1CD9B2B3BD57267 736AE7EC11C81947 CF8017AF59364A22 D7E98C7E5E6474FD 7BF07B6DD8095F4B 4C4BBBF6DEA15A6F 3308E9D0651FE5F0 FDA0D73E975069E3 E52CB3EF61DD4652 C4F8C78EC681FE67 7428D2A5C3ACF562 503E718AD89D9AED 9ECA2F9403BC6824 1823DA77422E5078 8370EF9C183185D4 3A0041EE2F52E2AB F18EB5B8456B6397 D1919DD5B95C3CB7 1C2757FC7522ADBF B7447AC8333B3526 E012994798F1645A 2B78639B05549EE5 96025FA4D6E47D14 8208A2A4C4B45709 B3B0E0259370A486 3E9F3592EED68166 5B87A71B9A0AE4D7 98F12F7F42DB2EAB 4BA9D42F4363DC31 B4AC6207A66C130B D26817EA78C2ED41 81EB79A5DFB8A278 073420DCF64F893D 968FFF1960E7C567 25849B254DE64143 810F0F129529AEF1 E31B28F6BD83041F 60AA1FD4E79D83D4 6C631D3E26BD9DB3 24B84A14E834ED20 E8C0438BB63FBD1C 3422B9EAAC5CFF0F 5D4EEF6752761D2B BA6E4F79A63B6599 2C47F53BED949DE3 B49D5FC1397764AE CE431FB23E4735A4 930F9D92BE770675 45A8F3E69634A533 FD27C1870E5F1E8D BC20704D72BB8BA9 7F4F32D420E52362 ECB0CD082F550BFC D9F2FEBB63880965 ADC0BE97DA67980F 0D761F85CA418848 FB6B951B707011C0 EA9124BAA5B9BFE9 1127D562B05C7D18 0BD533008927E8A9 02A0CEF9F783F51F A38B0AADC5736A35 2E127FE2EC209AA7 99430F3930C799F1 E03477387A48B833 C0252151A04CBA08 AEBBA2B3DA59E281 E107F65C8170B5D3 34085A0418F4B91A 6D5531267D0B0993 EDB3BFE649B0A4CD E335F1E93C4D73FE 2E61031A078CCE5C 13B281BB8B90CDCA AB7BEFF6622EEB7B 0071DF2B4995B1CB 8CFD1A723C1C307A E3CC75DDD7E641B1 38C38BC348707874 12ECFFDF2899BD4C

Read the ciphertext. Strip whitespace: 1,872 hex characters = 936 bytes = 117 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9A858DE45F56D9BC9 (name+name). Key = MD5(password) = 0dcc4bd9e114ebc42078977dc9125404, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 29 GUIDs as hex (shown below).

Decrypted: GUID list

  1 f62de41b-b9ca-69f4-b071-789fc8c07242
  2 f23b6f50-392b-3374-abbd-13a18ec36492
  3 e6de2f78-e246-0410-b876-34f0de9e1f36
  4 edd821e4-9f3e-5e48-81fd-4a97a3f122b8
  5 d6452261-2d99-66b5-b0fd-ffeb67824f09
  6 fec9f9f5-5c99-0fb7-bec3-11f6449ccd6c
  7 dd2d5767-dc22-0c27-b26e-b5d3342bac84
  8 d139aa49-acba-5a3a-8a87-7326929a3c9c
  9 dfc2d410-a3b0-7db1-b1b0-df515dbd8d10
 10 bb4b974f-6524-3d57-a7d6-0bf239749925
 11 10a8a890-2594-8d33-abe1-1613b2e0945e
 12 f1c86a6b-4fbb-4b6c-a617-9255fcdc5afd
 13 ae22b973-66ae-2185-8b59-e42e4aa8456f
 14 eddbee62-8e7b-0df1-a274-a9fef7084d30
 15 ee6a2176-aa33-8e4c-b57d-166157b6bc92
 16 566b8302-1854-44d0-8f82-e3f4ceecae28
 17 86bcf0d8-4f89-4eca-9ba8-540316029176
 18 a51ea729-85dd-3e0c-aeff-f148049a4742
 19 505e5f71-ca21-7b80-9c13-51d0ab255870
 20 b02de753-223c-67bd-8ff4-cfcd6767a88c
 21 bcdd4c2e-ac1e-79d9-9001-34de20e15900
 22 604194c3-b30e-2683-93d0-fc9d686154d5
 23 33884ed7-b57d-201b-adf3-bad61f16e3ff
 24 b99c1522-272b-0fcb-b708-ff7ceeedf31e
 25 a4a71af0-825f-3bb2-bc8f-7f622fe559b4
 26 a91fc3c7-a57b-46a2-a88d-c5ff8af4fb39
 27 15738c6a-9fff-80b5-a517-ecfdc79379dc
 28 8d0bfb09-b53a-7201-8f09-6d0accd1712e
 29 68f55a2c-df16-516f-b09d-5478d809a5ff

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 63056005738420844376722034875. Exactly this sequence comes out of new Random(670).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 82 of Run 22 (seed 528,385,484): new Random(528385484), Next(8,64) per post. The RNG predicts N = 29; the post has N = 29 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-07-27 19:02–19:13).
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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