201206261141 vn4nf

explained decrypted filler

3DES(name) ECB, 15 GUIDs, seed 477

Metadata

Post ID: vn4nf
Title: 201206261141 → 2012-06-26 11:41 on A858's clock
Posted (UTC): 2012-06-26 18:39:57
Timezone: UTC−7 · title 11:41 against posted 18:39 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 976 hex characters · 488 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 15
Filler GUID seed: new Random(477).Next(9) ✓ verified
Run: Run 3 (seed 1,063,142,882) (seed)
Draw: 57 · predicted N = 15 ✓
Machine boot: 2012-06-14 10:25–10:26 (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: namerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 976 hex characters = 488 bytes = 61 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9 (name). Key = MD5(password) = 34a14a42e98ff96095af56604e290cae, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 15 GUIDs as hex (shown below).

Decrypted: GUID list

  1 3ca99644-239a-8c52-8d88-98ee6f06a7ff
  2 c1b1c357-53cc-716e-8557-30999c9b441a
  3 0a505abe-00a6-118d-8c2d-e182d26f3570
  4 fd116af2-9101-32a0-8186-2666cd4f03b4
  5 cf127a98-cbf3-56b3-ace4-729c912a7c54
  6 f8ba57ac-acca-3591-a587-bb619acbf8c0
  7 5afa15e0-063d-552a-88bb-dab8a21699fa
  8 4edf531c-c988-6e42-a7b5-41e62352a0de
  9 630307a5-89c8-8697-988f-61863b47287d
 10 82ff0147-5e6b-1d2b-8d46-1e2be552ee8a
 11 68b76562-3f8e-60ef-8837-1e001119c562
 12 03cad666-2520-7315-bb28-c78f13533e52
 13 41f9fdfe-15c2-4e83-a364-a56ad2d6727c
 14 1d34e87a-fdce-57e4-9f4d-2c46e0609e21
 15 57394192-b197-7936-9450-007f7d3e0fcf

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 871353568167457. Exactly this sequence comes out of new Random(477).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 57 of Run 3 (seed 1,063,142,882): new Random(1063142882), Next(8,24) per post. The RNG predicts N = 15; the post has N = 15 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-06-14 10:25–10:26).
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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