201309140859 1mdgr5

explained decrypted filler

seed 792

Metadata

Post ID: 1mdgr5
Title: 201309140859 → 2013-09-14 08:59 on A858's clock
Posted (UTC): 2013-09-14 12:59:58
Timezone: UTC−4 · title 08:59 against posted 12:59 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(A858DE45F56D9BC9201309140859) = daeeb92203f67f1f3923af3c52440820 (name+title)
GUIDs: 8
Filler GUID seed: new Random(792).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 44 · 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: 2 · 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: 528 hex characters = 264 bytes = 33 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309140859 (name+title). Key = MD5(password) = daeeb92203f67f1f3923af3c52440820, 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 12010145-48b5-4e83-ac8c-20ccfd038ab8
  2 104e228e-5ce2-1396-b092-483db9dcc795
  3 3f300b7c-5a2e-3c3e-ab6a-397e9f44f825
  4 6d591444-4b5f-5f38-abe8-dd9326170b0f
  5 8946832c-5ef2-7d9f-ae24-cb2c5f89a784
  6 6a516e6b-cc62-64c4-b750-48f2f8e064b1
  7 a004034a-64d2-6058-8026-0ec3f367cf69
  8 6fade82d-9f9c-6168-b634-e11d50719412

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 41357666. Exactly this sequence comes out of new Random(792).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 44 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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