201209241421 10ejp1

explained decrypted filler

3DES(name+title) ECB, 11 GUIDs, seed 877

Metadata

Post ID: 10ejp1
Title: 201209241421 → 2012-09-24 14:21 on A858's clock
Posted (UTC): 2012-09-24 18:21:18
Timezone: UTC−4 · title 14:21 against posted 18:21 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 720 hex characters · 360 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201209241421) = c4485bc2e2021755259881bc09d64fa2 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 11
Filler GUID seed: new Random(877).Next(9) ✓ verified
Run: Run 34 (seed 83,105,000) (seed)
Draw: 246 · predicted N = 11 ✓
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: 720 hex characters = 360 bytes = 45 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209241421 (name+title). Key = MD5(password) = c4485bc2e2021755259881bc09d64fa2, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 11 GUIDs as hex (shown below).

Decrypted: GUID list

  1 50bb3d6e-f706-8c48-82c7-2245e77ff910
  2 133194aa-7610-1369-b458-9030f8cb6d28
  3 497e7d66-24d1-79a7-b075-7c46090f3635
  4 05b97dcf-9f6b-69a6-824c-12af09b8c4f1
  5 d30a0bcd-14ce-11c3-8a82-1e986695a405
  6 c30d1742-f8b5-85a3-8436-c5ddf21fc458
  7 7c54862b-0d63-78ad-a231-35c310b30c42
  8 74aaa429-bb92-3f52-8f48-4995efdb74c8
  9 3c7f5ff1-2df3-4165-8f36-946b98da9a5d
 10 b5ac7131-038c-65e6-99af-b079d2002e78
 11 e75b2546-499a-3f6c-ae9a-3cb4bbdcc8eb

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 81761873463. Exactly this sequence comes out of new Random(877).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 246 of Run 34 (seed 83,105,000): new Random(83105000), Next(8,64) per post. The RNG predicts N = 11; the post has N = 11 ✓. 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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