201210020420 10t3b4

explained decrypted filler

3DES(name+title) ECB, 20 GUIDs, seed 661

Metadata

Post ID: 10t3b4
Title: 201210020420 → 2012-10-02 04:20 on A858's clock
Posted (UTC): 2012-10-02 08:20:01
Timezone: UTC−4 · title 04:20 against posted 08:20 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,296 hex characters · 648 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210020420) = eef4beeee08bc37bba9ffd9898dee6bd (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 20
Filler GUID seed: new Random(661).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 1 · predicted N = 20 ✓
Machine boot: 2012-09-22 10:16–10:36 (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: 1,296 hex characters = 648 bytes = 81 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210020420 (name+title). Key = MD5(password) = eef4beeee08bc37bba9ffd9898dee6bd, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 20 GUIDs as hex (shown below).

Decrypted: GUID list

  1 56cbc41b-e250-0d5e-8621-c8b4ae094d89
  2 dcea863e-ed71-60e2-a8e2-a6852f3e4932
  3 7ef73c8f-dcd5-75fc-ab81-54d9e14c89a7
  4 b2545555-6738-539d-9015-d145215bf0a7
  5 4883bf89-43ad-5b7f-9280-3ac8e3dc6d8f
  6 7c583913-6871-1ec9-aa8c-426821fb16a2
  7 7b90444d-99c0-0561-bdb5-05be36ac0030
  8 1b2e745e-e8ef-071a-bf4f-94bb2e326993
  9 71bab808-5f19-6383-8d36-44952b83ff96
 10 72cb8def-2009-02cf-9d88-6f3b10f540c8
 11 d1d4d040-5c0c-277a-bb6e-33731064942e
 12 7b14d100-5d70-4240-8565-b5d2e27c5db9
 13 e53c6abb-0a24-006e-bd7f-bbaeee90f5a9
 14 cdbab22f-098c-32cf-aaea-19dce7814cab
 15 1b377c2e-2c02-5a44-be05-8d8ca97e828b
 16 a06475cd-98d7-7e98-87d6-384f410252ad
 17 6bc29170-cc25-6d27-8294-fb1b645af10d
 18 aa96e275-468b-7812-a98b-5c527e80b88e
 19 8bfcd8cc-01e1-56d7-8332-e3ca6f2c8d87
 20 92614b0b-f4e5-2399-9b60-c542f21bdafa

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 06755100602403576752. Exactly this sequence comes out of new Random(661).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 1 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 20; the post has N = 20 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:16–10:36).
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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