201310080715 1nz6kt

explained decrypted filler

seed 247

Metadata

Post ID: 1nz6kt
Title: 201310080715 → 2013-10-08 07:15 on A858's clock
Posted (UTC): 2013-10-08 11:15:21
Timezone: UTC−4 · title 07:15 against posted 11:15 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 528 hex characters · 264 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201310080715) = 89e5c5223ad108c5ad01de756aa37243 (name+title)
GUIDs: 8
Filler GUID seed: new Random(247).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 161 · predicted N = 8 ✓
Machine boot: 2013-09-12 09:30–10:30 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 8 · 5
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

0EC4FF88AF060A46 30A1898EA680F9CA 4E602DAA465ACE0F 74BCA5C278CD72A5 D9358D4F204F5E10 62DD2C871959ACD0 4D3ED1339BB75A24 F998F287991BAC65 A52D3414C62A5C21 997AC642DAA50140 31E627F725FFEB45 C32F54E92D9FB061 3B6AD69F527B7EB2 63049B66347B8FED 898AEA86D5BF03AE C892C8C4C86E2FA4 E4D19CEA9F2FB2D3 1E81564705111014 B9E4D1CD4DCCC284 B535968852D721BD C95300FFFF0EF744 F8C495F7C3DE5868 E9DF3E27224EB2FC 0A9B104407660CC9 5844DA510852F471 1322F2CF8BAE7DCB C4CD03D47DA83EA3 091709ECB70BDA42 C1BC0D4FBA0A48F2 5C008FC19A77D93F 09A5CDB5ABDD6DF7 7C9F230BBAB07964 9138150D94A5C837

Read the ciphertext. Strip whitespace: 528 hex characters = 264 bytes = 33 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201310080715 (name+title). Key = MD5(password) = 89e5c5223ad108c5ad01de756aa37243, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 8 GUIDs as hex (shown below).

Decrypted: GUID list

  1 74c014af-3131-610c-b298-bd5f6197726c
  2 843619f1-7f88-24b6-af3f-091cc07ad7fa
  3 a9553c29-7708-3cca-8254-5e9b3d274f7c
  4 172078a4-d9da-2737-aeb4-91cc06aa6204
  5 6b3086e3-6019-68c3-a4c2-c6c9df29b091
  6 759ec6e5-cf80-3855-b519-da6b5b8cda20
  7 bf313246-d6c9-566e-b85c-26913a9402fa
  8 c2ad4b14-42e5-31b4-bb90-2dc38a10618d

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 62326353. Exactly this sequence comes out of new Random(247).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 161 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) per post. The RNG predicts N = 8; the post has N = 8 ✓. The seed is the machine's uptime in ms when the app started (boot 2013-09-12 09:30–10:30).
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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