201206270735 vnnc0

explained decrypted filler

3DES(name) ECB, 17 GUIDs, seed 42

Metadata

Post ID: vnnc0
Title: 201206270735 → 2012-06-27 07:35 on A858's clock
Posted (UTC): 2012-06-26 23:33:40
Timezone: UTC+8 · title 07:35 against posted 23:33 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,104 hex characters · 552 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 17
Filler GUID seed: new Random(42).Next(9) ✓ verified
Run: Run 6 (seed 652,173,660) (seed)
Draw: 7 · predicted N = 17 ✓
Machine boot: F 2012-05-15 19:06–19:16 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 5 · 1
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: namerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,104 hex characters = 552 bytes = 69 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9 (name). Key = MD5(password) = 34a14a42e98ff96095af56604e290cae, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 17 GUIDs as hex (shown below).

Decrypted: GUID list

  1 6ec153da-b449-6dab-9c31-988668a48ae5
  2 1f94a9a3-b4a4-1255-9717-29ec53b5e9fa
  3 a367992b-24cb-11ea-81a3-b374f04a3c9d
  4 050d700e-7676-42e8-988d-ecedf61839ec
  5 1902e5e1-8fab-12e8-a74e-6532e5f8a7e8
  6 29e782e1-9079-2cfb-bddd-d323f8413300
  7 6b1069fe-fd1a-6101-ae49-1eebee8e4f0c
  8 f6f89cea-785e-49ab-aa43-02dd039fa642
  9 aaf730a4-f852-16a2-88f8-ed41237d3a0d
 10 d744720f-e37d-62bd-80b1-252ad88e55f7
 11 a2d2b0b7-e840-211e-a861-09d55dd45772
 12 853ced2c-b496-2c65-bcb2-4f5459ebd6f6
 13 53a0b431-9f58-4c2b-9771-5cdfe13204f2
 14 0ac51052-f2d7-2a7a-b3e6-0383c56284f4
 15 9d676050-02d6-3829-ac31-042a9cb640b8
 16 6abdc073-2989-25d4-8747-1e30d81306a1
 17 578ee349-cddc-4b75-b5b3-6f6de4a0ef15

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 61141264162242324. Exactly this sequence comes out of new Random(42).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 7 of Run 6 (seed 652,173,660): new Random(652173660), Next(8,24) per post. The RNG predicts N = 17; the post has N = 17 ✓. The seed is the machine's uptime in ms when the app started (boot F 2012-05-15 19:06–19:16).
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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