201309161832 1mj6j1

explained decrypted filler

seed 701

Metadata

Post ID: 1mj6j1
Title: 201309161832 → 2013-09-16 18:32 on A858's clock
Posted (UTC): 2013-09-16 22:33:00
Timezone: UTC−4 · title 18:32 against posted 22:33 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(A858DE45F56D9BC9201309161832) = cfbd6235ccbf161f55e8506ff81c13f6 (name+title)
GUIDs: 16
Filler GUID seed: new Random(701).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 101 · 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: 0 · 0
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

FB0923BD00CEA754 65D44D97DCC19AD6 F9491D77A30385A8 31982DA078AA38C2 B276659326F313AC 37CFC9AEF4EB2EF0 C8975C992D5EEE0C B5AD8141D1D3C776 417D8496AA84D891 1CC4055B07503D79 5C0770E7192FC464 41FF90A195BBBA35 FC652008B7819CE8 1CE8425448CC113B 7D2C5DAD7F2D5FF5 EB70E7D065572C45 805D89E9D6A449D9 57432A34BC880D93 DE5D57FB508B306A A54C72A5D864419F F23C85898E57C4C0 1232A4299B4C2BDB 58E9C5A32C36DAF1 1979754F9E031031 2F99690049749BE9 EFFAB94FABF1C671 D9A6AB517412CE67 412F1F5035CFD75D EBE6F236198B8BB1 DF7501CA890FD6AF C594FC30EE118844 96DEA6E03E30B108 03D0BDD63CBBED86 D7F3FFAFBD494954 32754A238E58E711 2F326BA120E2800F CA8CA17E4C93FFB4 CE52AEB8E72E6C4B A011CE56FA1CE6FD 840AC711884C551A 442F3295E6BF82F8 BB4C4E675E28A982 B094F47556EF41DA 18C10F905704E0B6 DAE3D31A8FF40E71 41D9D2222CFB093A CE8885D19E81DB93 48A6623CB6367FE7 76A11130CD5A9C8D 9C0807CD9355F093 E5D8F6A5C9EC1985 B0DC033350173413 47005CAA13DEB614 47773415B81754E9 5EC02410FDE7D95A 53D5ED426C42C049 753C9ABF95441BF0 6307425E81B405BF BD92389F3DD7C521 4BBE6C458384E15D BDAF08F3DB23E98A EE5BD077E54140F9 AEB53FD2ABF31F51 6A466F6FF08585BE 7C94EE56B68786B2

Read the ciphertext. Strip whitespace: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309161832 (name+title). Key = MD5(password) = cfbd6235ccbf161f55e8506ff81c13f6, 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 87151fe6-8ce4-8ba9-ac4f-253786d89021
  2 fb02962f-782f-4597-b8c9-43629a075161
  3 5b079eaf-fcbc-65d2-b0fe-e9b1be7b4f76
  4 eff16842-347e-148c-86cc-f418d84f488e
  5 9e4fe8c9-bb84-676a-afc9-c4a21219a449
  6 18869cdd-0cf3-1aac-b518-b6eb406038e0
  7 e008005c-32f7-8cac-85fc-61ec2fe6ba5e
  8 3ed224e5-d398-16d2-84d6-7eecbfce0cdc
  9 3b9a1601-be97-6c29-ae8d-e9f315a7eaa8
 10 ad6bdd4b-5330-6b59-8d24-19609590a15f
 11 83bba687-ddf3-6ebc-964f-2e1a951508e9
 12 5eddd606-a936-62c6-8bba-a99d4b95603e
 13 acd3c7fc-406a-4136-9b4f-ee252d2b97c9
 14 ad302e5d-9165-1da8-acd5-c1a2b69bf8c6
 15 2d58bc02-d0db-5f2f-a7a3-643ab12bb362
 16 67aed799-4e95-75c8-8baa-610761e23338

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 8461618166664157. Exactly this sequence comes out of new Random(701).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 101 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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