201206272244 von46

explained decrypted filler

seed 349

Metadata

Post ID: von46
Title: 201206272244 → 2012-06-27 22:44 on A858's clock
Posted (UTC): 2012-06-27 13:43:04
Timezone: UTC+9 · title 22:44 against posted 13:43 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 912 hex characters · 456 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
GUIDs: 14
Filler GUID seed: new Random(349).Next(9) ✓ verified
Run: Run 7 (seed 629,367,141) (seed)
Draw: 24 · predicted N = 14 ✓
Machine boot: F 2012-05-15 18:57–19:13 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 15 · 8
Tags: automated (decryptable)2012Encrypted masked GUID listkey: namerun: seed

From the post to its content

As posted (encrypted)

479053817E8AB8C6 73A5464E53E114E4 1151F60F89C2CD34 337FD21F0C738DFE 7A4349243F5020BF AF004406D9AB3867 CE6C98FBE8A52344 D0F77422885E67C6 D2CE8AACECE12921 61C46333F95600C2 17A24AF83F8ECA04 20E20DF67A0C5228 F0B294B276F6A699 80BB4E97A08B5D50 5EF227398ED61DE1 6139A7F56E63EF5A 92CC842DFA80D63A C9034CBFB4FBFA13 FE0009932C9E7742 89B456A7BC276F9E D1A2816C8D2D8E5A 32A0FB3C212F1EED 67303C93F0951151 FD7DAF8B7AD26BFC 6973F462C7D2954B BAD785424086EB15 A74735EAF07F3B83 6D47EC2FDF3454B1 078D51F6C8CB9130 3304D8A303E34EE0 3E07C3495A45E8F2 A4973A48788470B5 FCFC8191BB7732F5 2329415E5261B82F 94D9FFBF0679B793 97A48A9C8079CFEA ABEA3855BDEA8D44 7E54CD459E3A399A B934150C0A4BE89E DD1E8895FDABAD06 21DADEA01632172B 1BC440D593B904D8 B96523A03BC93D36 CD943A0AA7AAF25A 95C54777231A35D9 0E8AF98B1BB97771 D282C0EF2499564D 4F62535797507655 D2F7BD81234688A6 97AC60885C8893AF 2F113F930ECF2318 449288DA34F1AD83 7FBC718A682F79A4 B4C3C6233E962522 5EBECA36EEC79FA9 867A9CC64E8A28F3 5DACFFBA8FF64DBD

Read the ciphertext. Strip whitespace: 912 hex characters = 456 bytes = 57 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9 (name). Key = MD5(password) = 34a14a42e98ff96095af56604e290cae, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 14 GUIDs as hex (shown below).

Decrypted: GUID list

  1 fe9dce9d-29b0-05f3-b873-f8c32627d7e0
  2 2ea51181-176b-14ae-84f2-272195eb5380
  3 c39b7900-d576-606d-8698-1af92357e1dc
  4 b9d2f3d4-460d-0421-8e62-a333bb89b9ad
  5 ee24255f-7093-6bb0-b38f-94544f3b5840
  6 d272787e-ab69-4346-86e9-0d4b5dcb8406
  7 282147b3-d687-223c-826b-a00db6ef6ee9
  8 f53bbf3a-69ad-4740-8bd3-7ae852cb2a59
  9 d1414c05-8b7e-1716-802f-ebb643a6520c
 10 a4ab05d4-d5db-8bf1-86be-6c8b76c35abe
 11 6564a6dc-e0c1-3923-ac63-c8e6f2cf63ca
 12 fd790997-8b04-8a80-b49a-afd8f31fa98f
 13 45036e6f-01db-41bd-9f79-1ce3ca18e8ff
 14 d03dfcab-51ef-013d-a4d8-ea203b646e1b

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 01606424183840. Exactly this sequence comes out of new Random(349).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 24 of Run 7 (seed 629,367,141): new Random(629367141), Next(8,24) per post. The RNG predicts N = 14; the post has N = 14 ✓. The seed is the machine's uptime in ms when the app started (boot F 2012-05-15 18:57–19:13).
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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