201206261115 vn2vf

explained decrypted filler

seed 559

Metadata

Post ID: vn2vf
Title: 201206261115 → 2012-06-26 11:15 on A858's clock
Posted (UTC): 2012-06-26 18:14:09
Timezone: UTC−7 · title 11:15 against posted 18:14 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)
GUIDs: 16
Filler GUID seed: new Random(559).Next(9) ✓ verified
Run: Run 3 (seed 1,063,142,882) (seed)
Draw: 21 · predicted N = 16 ✓
Machine boot: 2012-06-14 10:25–10:26 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 10 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: 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 885ece44-9cd4-6c5e-8f56-f8a1ccbf1f2a
  2 d7c0249c-c77a-7201-b122-1df440d0a54e
  3 e7e4b547-fa0f-4bbb-89c9-5d52fe69b0f6
  4 3888a80b-1089-70b0-bd2e-9bf3353ed9c0
  5 5ff22202-660f-520f-bdfc-78573c108dfc
  6 d002b39e-741f-0452-ac13-876956a7b670
  7 ceec8f20-add2-3a9d-a26b-6a4caa84529a
  8 1b0b88bb-e9d5-7b34-b965-03d89a348d2a
  9 dfe7fc30-517f-1e2f-bc32-5a042e16d763
 10 a0b3f514-98c2-363d-9dc6-000ffe9e5eab
 11 7754390b-9d99-15d5-be1c-56e9116836dd
 12 27885f0b-bdae-7271-a19e-5e58cd809f16
 13 cef2cf8f-16e1-8dda-804e-8c51cd6f500a
 14 a05b50a2-574f-2e9c-8c94-8ba727b11d3f
 15 4979756f-a1aa-2d9d-96ed-5ce2891464f4
 16 646416f7-ca5c-1ced-9b59-fc6588c1d699

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 6747503713178221. Exactly this sequence comes out of new Random(559).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 21 of Run 3 (seed 1,063,142,882): new Random(1063142882), 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 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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