201309181832 1mo8lb

explained decrypted filler

seed 412

Metadata

Post ID: 1mo8lb
Title: 201309181832 → 2013-09-18 18:32 on A858's clock
Posted (UTC): 2013-09-18 22:32:57
Timezone: UTC−4 · title 18:32 against posted 22:32 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,296 hex characters · 648 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201309181832) = 8d858ec5817a98ff64baab2e3b17a162 (name+title)
GUIDs: 20
Filler GUID seed: new Random(412).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 110 · predicted N = 20 ✓
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: 3 · 0
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,296 hex characters = 648 bytes = 81 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309181832 (name+title). Key = MD5(password) = 8d858ec5817a98ff64baab2e3b17a162, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 20 GUIDs as hex (shown below).

Decrypted: GUID list

  1 2f13776d-e6bd-87f9-88d8-c82d6e8a6d88
  2 12d82271-621e-623c-a419-c8700c7dcdd3
  3 5b687cfc-9c5a-61a6-9821-5e98547e3b92
  4 36ee1632-5ea1-4908-914d-90302f9626bd
  5 5ab967b8-641e-1698-9157-71d055da8e96
  6 96f7e869-d048-5123-9cd6-847e5e832486
  7 66db9e33-344d-4252-8b97-0fcab2de427e
  8 1b73da3e-ae55-1c5a-888a-1e99fddb60e3
  9 540dea8e-1f52-8cbe-aac0-86b9395c9cc4
 10 95519e5d-bbdd-1437-b108-7491cf24f856
 11 d823fa9e-b314-7dea-88d4-e1e3073036dc
 12 5e608fa1-c701-1970-847b-62cd67df02be
 13 1857c44d-192c-7d96-9a13-e8b970317b4c
 14 ec2ea799-a8a3-721b-8f27-371f74f527e7
 15 449ddd04-b2c6-37e1-b4de-385ea1df9b21
 16 12013a46-625d-29c7-b11b-e75dfb547d9f
 17 4fb4431c-920c-0dbc-b2a7-f2b366c826d3
 18 a1846e9b-2851-3e36-b697-9e59ec6046b8
 19 d40013c1-aad4-79a8-914b-e25488a62adc
 20 f325a3cb-0387-748a-ae5e-136751326cc9

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 86641541817177320377. Exactly this sequence comes out of new Random(412).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 110 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) per post. The RNG predicts N = 20; the post has N = 20 ✓. 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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