201209231318 10cjdk

explained decrypted filler

3DES(name+title) ECB, 14 GUIDs, seed 271

Metadata

Post ID: 10cjdk
Title: 201209231318 → 2012-09-23 13:18 on A858's clock
Posted (UTC): 2012-09-23 17:18:20
Timezone: UTC−4 · title 13:18 against posted 17:18 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(A858DE45F56D9BC9201209231318) = 252fa2ae5c9033fbff823c47bc5a2157 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 14
Filler GUID seed: new Random(271).Next(9) ✓ verified
Run: Run 34 (seed 83,105,000) (seed)
Draw: 36 · predicted N = 14 ✓
Machine boot: 2012-09-22 10:23–10:24 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 1 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 912 hex characters = 456 bytes = 57 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209231318 (name+title). Key = MD5(password) = 252fa2ae5c9033fbff823c47bc5a2157, 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 400e0896-6c13-28fd-88d8-d8dda91e08f1
  2 1dd268de-6678-3e84-beca-73a6ed09202d
  3 19f37a8a-ee68-1795-9e0e-de0f4545d6f7
  4 206cf10a-96d5-350a-8d1e-b8c7f97fdace
  5 18a0652a-326a-5ef7-8c80-4008a76d5f10
  6 680bb9ce-2fa2-37f9-b932-f9f358923bf6
  7 e36fbe5d-3c86-2b30-8060-7610ed2ef7b0
  8 d9cf23b0-b6a0-3982-84c8-30a874c060ea
  9 1ca07402-d493-489b-935c-f7d5f069eaf7
 10 dd02e45c-9608-11aa-8edd-ce2139aa0b7d
 11 fa00ad2d-dc8a-8b14-81a9-23bbfc4ddecb
 12 14ac8c35-a608-0846-9bc5-89132788ebcc
 13 5c90c057-fe8d-81df-86a9-b8439469e936
 14 6594b13c-c0fe-4651-9ea2-3c9c68e7e48a

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 23135323418084. Exactly this sequence comes out of new Random(271).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 36 of Run 34 (seed 83,105,000): new Random(83105000), Next(8,64) 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 2012-09-22 10:23–10:24).
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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