201309042159 1lq85r

explained decrypted filler

seed 294

Metadata

Post ID: 1lq85r
Title: 201309042159 → 2013-09-04 21:59 on A858's clock
Posted (UTC): 2013-09-04 17:59:54
Timezone: UTC+4 · title 21:59 against posted 17:59 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(A858DE45F56D9BC9201309042159) = d2f8649a469d28d638bd6f4488e02090 (name+title)
GUIDs: 8
Filler GUID seed: new Random(294).Next(9) ✓ verified
Run: Run 52 (seed 1,430,705,843) (seed)
Draw: 39 · predicted N = 8 ✓
Machine boot: 2013-08-14 07:34–10:34 (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 = A858DE45F56D9BC9201309042159 (name+title). Key = MD5(password) = d2f8649a469d28d638bd6f4488e02090, 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 9bb597b4-732b-23ac-95ab-23dfaf423ed9
  2 9b80a5d0-3b15-09fc-88a3-e15651869d02
  3 b1e7ac21-2061-2c7b-a5ab-d224e0ee4866
  4 052dbd4f-92e4-22a1-ad7c-f1fe91ec48b1
  5 0f1a92ee-7a97-82c8-a511-ce7e2d01df74
  6 ff3190e8-d0df-4849-be1e-18da4b107cbc
  7 74ccbada-a87e-5942-8c11-d5ecfad7f2fa
  8 c8556ca8-525b-851c-b783-06aaa4ce648e

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 20228458. Exactly this sequence comes out of new Random(294).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 39 of Run 52 (seed 1,430,705,843): new Random(1430705843), 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 2013-08-14 07:34–10:34).
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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