201206270835 vnqoe

explained decrypted filler

3DES(name) ECB, 16 GUIDs, seed 642

Metadata

Post ID: vnqoe
Title: 201206270835 → 2012-06-27 08:35 on A858's clock
Posted (UTC): 2012-06-27 00:33:47
Timezone: UTC+8 · title 08:35 against posted 00:33 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(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 16
Filler GUID seed: new Random(642).Next(9) ✓ verified
Run: Run 6 (seed 652,173,660) (seed)
Draw: 13 · predicted N = 16 ✓
Machine boot: F 2012-05-15 19:06–19:16 (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: 1,040 hex characters = 520 bytes = 65 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 16 GUIDs as hex (shown below).

Decrypted: GUID list

  1 9da84c9c-77f6-1fc1-9c02-9facf16b4921
  2 8af80085-8b25-13fb-a729-65516adcab24
  3 ecfd8491-20f9-4076-9b43-c249b162962b
  4 97d22f07-c5b8-5502-b0fd-d3d495bddf29
  5 10a5c758-abfa-020b-ac2e-59708e9e6b31
  6 25bf54fe-26ca-5f82-94d2-c8fa158e9ab6
  7 f27b081a-54f7-5709-af50-c3ad57760269
  8 7bf59612-a749-4c63-a768-b7f833942a86
  9 8ea59b13-6541-378d-a25d-a566503a5b7e
 10 a814d18c-a601-01b8-abee-0412eaca708f
 11 9dc2cddf-eb86-2ec6-beb1-4d6d08080677
 12 5d4fea36-3410-6dbc-ac0d-38ea5bf2b010
 13 c7b12605-6e4d-8743-baf4-a7ef3261c5c6
 14 8d8d1ca1-db61-467a-a48d-bde303b89125
 15 0fe0e223-702f-336c-a600-3e6a56de3b7e
 16 50e9a0de-57cf-84a8-82ac-9bfa5d81e5f2

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 1145055430268438. Exactly this sequence comes out of new Random(642).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 13 of Run 6 (seed 652,173,660): new Random(652173660), Next(8,24) 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 F 2012-05-15 19:06–19:16).
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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