201210260103 123yrq

explained decrypted filler

3DES(name+title) ECB, 10 GUIDs, seed 635

Metadata

Post ID: 123yrq
Title: 201210260103 → 2012-10-26 01:03 on A858's clock
Posted (UTC): 2012-10-26 05:03:31
Timezone: UTC−4 · title 01:03 against posted 05:03 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 656 hex characters · 328 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210260103) = 9b83306279bd45c8d8fc41e2f89653eb (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 10
Filler GUID seed: new Random(635).Next(9) ✓ verified
Run: Run 38 (seed 1,045,884,937) (seed)
Draw: 45 · predicted N = 10 ✓
Machine boot: 2012-10-11 03:41–03:51 (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: 656 hex characters = 328 bytes = 41 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210260103 (name+title). Key = MD5(password) = 9b83306279bd45c8d8fc41e2f89653eb, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 10 GUIDs as hex (shown below).

Decrypted: GUID list

  1 cfd11384-65ac-40ce-a226-918848a6a31e
  2 760eb3f9-852b-1b80-ab04-07c0c52a447d
  3 d6dd90ef-4fc2-5f67-bca4-a17eb1dba2bc
  4 7bae8aba-9d02-0189-8e02-83a46f563099
  5 bed41164-b88c-8753-aca3-4325a3689c43
  6 accd89df-bf9e-466f-80e1-619f657e1dbd
  7 0b49648f-5cfa-38a3-b228-cb48d235b648
  8 006ef969-5237-0322-b26d-5650ba04d77a
  9 d790999d-4855-4eab-9bce-3e84c4ca7044
 10 84e90262-d9d8-3f98-8724-6cd71ed706ec

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 4150843043. Exactly this sequence comes out of new Random(635).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 45 of Run 38 (seed 1,045,884,937): new Random(1045884937), Next(8,64) per post. The RNG predicts N = 10; the post has N = 10 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-10-11 03:41–03:51).
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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