201210071405 113gl6

explained decrypted filler

3DES(name+title) ECB, 16 GUIDs, seed 824

Metadata

Post ID: 113gl6
Title: 201210071405 → 2012-10-07 14:05 on A858's clock
Posted (UTC): 2012-10-07 18:05:14
Timezone: UTC−4 · title 14:05 against posted 18:05 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,040 hex characters · 520 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210071405) = 67920d35d75e59f1a85adcd413a96d78 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 16
Filler GUID seed: new Random(824).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 390 · predicted N = 16 ✓
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: 0 · 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: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210071405 (name+title). Key = MD5(password) = 67920d35d75e59f1a85adcd413a96d78, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 16 GUIDs as hex (shown below).

Decrypted: GUID list

  1 a9a65579-19da-1d49-809e-36156c8a2e39
  2 e57b57cf-2e88-5644-8cea-85b4143445e0
  3 4a730561-a33c-6fbb-b025-9c1dc870bd14
  4 e8ed73c5-2510-3eeb-b578-17187b2efbea
  5 dc763a8f-4090-2784-8b04-951dc347c8cb
  6 8c4a9bf8-3ab4-53a1-b58a-4b5ce3e94bd9
  7 3a4a5467-73bf-0b1b-84c2-1c65d4a5491b
  8 1f4c6999-8bea-7a8f-8bb2-c71e417f6023
  9 cfe7ffb5-d11b-86f0-80e4-91cb5932aca9
 10 a662dec1-4417-10bf-9aa1-609aa7353375
 11 ffb79c02-a136-3161-8941-b18487fbd951
 12 a15431ad-3fed-6c4f-ba2e-85721b37a8da
 13 7f2afbaa-36da-0cc8-a693-ddedb0e656b1
 14 2d008cb1-8761-14e4-84ef-12e93a454406
 15 822e29b1-246f-6a4d-a92f-cb3209405eb1
 16 32d1c4ff-a677-5cc4-bc6b-dc677ad57998

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 1563250781360165. Exactly this sequence comes out of new Random(824).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 390 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 16; the post has N = 16 ✓. 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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