201209241237 10djjb

explained decrypted filler

3DES(name+title) ECB, 10 GUIDs, seed 820

Metadata

Post ID: 10djjb
Title: 201209241237 → 2012-09-24 12:37 on A858's clock
Posted (UTC): 2012-09-24 03:37:26
Timezone: UTC+9 · title 12:37 against posted 03:37 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(A858DE45F56D9BC9201209241237) = 0845e98761ac00b1ee6cd7b259ca4c5c (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 10
Filler GUID seed: new Random(820).Next(9) ✓ verified
Run: Run 34 (seed 83,105,000) (seed)
Draw: 173 · predicted N = 10 ✓
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: 656 hex characters = 328 bytes = 41 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201209241237 (name+title). Key = MD5(password) = 0845e98761ac00b1ee6cd7b259ca4c5c, 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 c5d60ed5-8442-1fac-a766-3a11347521f3
  2 1b315159-67dd-3714-ba3b-998ac9a6f83c
  3 a45a41ad-8760-8996-a1cf-f22b2d487c6d
  4 6f792a2d-a21a-52de-993d-91d164e03c80
  5 ccc0866f-ef5e-3d4a-9311-afec8777dd8f
  6 04e7d476-e1f9-1c70-89ca-2ec755af840f
  7 5ba0922a-2ad3-2abb-a14b-660ba637d125
  8 e70e7a33-0f58-73c1-aad9-c11107cb9794
  9 29137f77-c12d-3bc7-bfb6-46ff276daf9b
 10 913e2b34-efc0-52a5-8a88-09f22e73b386

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 1385312735. Exactly this sequence comes out of new Random(820).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 173 of Run 34 (seed 83,105,000): new Random(83105000), 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 2012-09-22 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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