201310041914 1nr6yp

explained decrypted filler

seed 286

Metadata

Post ID: 1nr6yp
Title: 201310041914 → 2013-10-04 19:14 on A858's clock
Posted (UTC): 2013-10-04 23:14:54
Timezone: UTC−4 · title 19:14 against posted 23:14 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 528 hex characters · 264 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201310041914) = 6e73a0a54fbbeac32ba8a76d3cab908c (name+title)
GUIDs: 8
Filler GUID seed: new Random(286).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 154 · predicted N = 8 ✓
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: 10 · 2
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: 528 hex characters = 264 bytes = 33 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201310041914 (name+title). Key = MD5(password) = 6e73a0a54fbbeac32ba8a76d3cab908c, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 8 GUIDs as hex (shown below).

Decrypted: GUID list

  1 dfc15b7b-2f84-102c-b618-8b2d303a060c
  2 dbdcd18f-94c9-6796-8199-5ffed98f3980
  3 a1f82017-8c78-6732-90b0-54fef7c2fd84
  4 d82688e5-a5f5-5f3b-81f2-91e175895225
  5 4772fa82-43d1-2d41-b1de-e82d3dda1c7d
  6 35f67ee4-ecaa-4b2e-84df-d3519ed5c689
  7 c3d2ecf6-6657-03b4-a7b1-8a42fb2c01cd
  8 7187dae9-4e9f-8541-ba54-905d36cfcc68

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 16652408. Exactly this sequence comes out of new Random(286).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 154 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) per post. The RNG predicts N = 8; the post has N = 8 ✓. 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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