201210281459 128b02

explained decrypted filler

seed 800

Metadata

Post ID: 128b02
Title: 201210281459 → 2012-10-28 14:59 on A858's clock
Posted (UTC): 2012-10-28 19:00:00
Timezone: UTC−4 · title 14:59 against posted 19:00 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,104 hex characters · 552 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210281459) = 5ab932c248d1daacbfd9120a202497aa (name+title)
GUIDs: 17
Filler GUID seed: new Random(800).Next(9) ✓ verified
Run: Run 38 (seed 1,045,884,937) (seed)
Draw: 66 · predicted N = 17 ✓
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: 26 · 20
Tags: automated (decryptable)2012Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

85486A2E40510870 2C49086DE942B4E8 CF76B2168D5C0759 5DD513485845948E BE06922480CDE181 407B5D51DDBD7CF3 8F4A62A7E731524E BAEB09808F4955A8 A3BD9585AC933D06 C1CABF456EB9F623 0E372F2DA09367F0 5409CF48F5A28F49 95AB469F061A274D 93B73267329D4E71 04792D9A7190B166 5AAA3633D931056A 4B5071E1B53B3D21 DF726EB536C5C917 A775FA271F8D13D2 564DD8D9659FC5E8 59F5DB90489CEFD1 85FB68D209D954BC 677A18FE73AF2E63 34BB06CC5AFE2759 ABE1C40DD16FD8F8 91431E8E01B76346 81D38AB4D82E2D76 AFC768ACFCDB2CA6 437F1F576E1BC7E7 69102A7D213641E9 36E3CC6DD5EB9889 AA4D71DF24D719FA AF9845B13EBC0632 83BB38C8D762991A 8B1CB0F48A246364 1A52F938A139CE95 5C39B49B2B9A2D36 2D9ED80F0D140084 32606D7DBB387163 CDF3350E4D94214E 21AF086074F74F18 AFBA3E6217213CB2 3A12C69FE82A076C 43F806B8E84B73B9 38B4B8BAFB8A7492 FB105E5B86A26371 E5D31C92600F95B3 DCD013B9F7CDDF29 3B9E8CDA0DBD3568 72EF6589FD24568F AE5CD3DF020A70EB D26DA0F780E81F4C F65B9AC8DBD8C5C5 71841D483EE1D293 BF7DC21B70F1F7FB 1C8B683EAD9FD7DF 5BA178211947EB96 EEA8CED9C187ADAD 7372401777EABF57 92C96C666B022DB9 4889FB6FEAB6A5A1 2E92B380066AFDB9 041E76643D5CBF12 AAE93420A2BF9D53 3D663696CC91C89F 7892B4DD008E8F9A 48C2B2AC97AB9F67 75B09D85B34299B1 4062F71F54CDBDB5

Read the ciphertext. Strip whitespace: 1,104 hex characters = 552 bytes = 69 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210281459 (name+title). Key = MD5(password) = 5ab932c248d1daacbfd9120a202497aa, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 17 GUIDs as hex (shown below).

Decrypted: GUID list

  1 f84c615c-f88e-55fe-a8cf-2d5878a39d52
  2 6e05409b-ea65-46d5-a0cb-8e9655d6df5d
  3 31e30143-e689-8ff0-ac88-f2e1a7fc7298
  4 75b74eb9-55af-2f5d-aaab-1c7b91cb9ba6
  5 2444f241-9003-3d8a-8ab5-3d26fab586f1
  6 3ea6e900-1945-61dd-b0c7-db407f30088b
  7 91df167e-6b59-3d4c-b5f4-ea2e333a31fb
  8 097ec1f6-dc1d-7dea-932d-fac0da073fcd
  9 1330aa73-26bb-86a5-bd01-c6c852741a70
 10 0f7ed624-fe3d-2034-9d1b-0dac73860365
 11 3b2b5b3c-a7b2-6e1d-8801-0f0cdd877055
 12 04cc154a-1920-0947-9be5-4fe15ad09f3f
 13 716d8d39-4ad8-5583-963e-89765de9a0a1
 14 e9e827ab-65eb-653d-9d57-2c243c25e7e4
 15 0cf2a738-0278-8f36-929d-96567a372ad3
 16 28f3ee7e-31e6-5aa7-bba6-e7b3178ceae2
 17 d90a00bf-8657-1d7f-bf09-5675372c9196

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 54823637826056851. Exactly this sequence comes out of new Random(800).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 66 of Run 38 (seed 1,045,884,937): new Random(1045884937), Next(8,64) per post. The RNG predicts N = 17; the post has N = 17 ✓. 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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