201206261107 vn2bl

explained decrypted filler

seed 360

Metadata

Post ID: vn2bl
Title: 201206261107 → 2012-06-26 11:07 on A858's clock
Posted (UTC): 2012-06-26 18:06:10
Timezone: UTC−7 · title 11:07 against posted 18:06 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 656 hex characters · 328 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
GUIDs: 10
Filler GUID seed: new Random(360).Next(9) ✓ verified
Run: Run 3 (seed 1,063,142,882) (seed)
Draw: 16 · predicted N = 10 ✓
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: 7 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: namerun: seed

From the post to its content

As posted (encrypted)

037614246081CD12 FD66D61F210EC9EC 2E6A1CB9D0547164 EDBF08A92835F69F 8ECB79CB44D3F030 A869CD60B8358595 AD525A1CC5B5FFF3 932BC4CB49D3E118 CD7D2020784D9F45 50C986AA1AE6BC3E 11F7FF7BEDDC3D8B 2D1FC020D8A8D9B5 FD8D911C80033039 EF536F5BDA00B56F 4012C4F141FD5D78 8EC9F2F3D4EC2E7D 138A904A35EE856F 06810F9B34A98DCB 38BD40129DB30123 BE2D4065FD88391C 26A4DD73AE7531F4 B5B1B966D0E1A86F 9224B9E43F060856 49408CD7D604BAA1 656C1A6095C15FC5 D0244D7242E20A2C F1238E1550B229E3 66DD4552FCFE910F E98FC4A6954C17CE 346C21762D52ADD1 EF55E81D85D9F4C2 8D0CD42ABFB00EB2 DF250C23D95D8805 4131E7AD285CDA2D E37494A7A8D7123E 422F35A891C4A23F ED5F3BFF52672BE6 0BDAB11A33978B26 6D23922C66464DAC 2EF18CCFA1D2B0A9 5DACFFBA8FF64DBD

Read the ciphertext. Strip whitespace: 656 hex characters = 328 bytes = 41 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 10 GUIDs as hex (shown below).

Decrypted: GUID list

  1 4347420e-babb-72ef-8f1c-4bb962c906fe
  2 1a1b1b20-c29e-4f61-8d8b-d94104dfa035
  3 2fd0e957-c62d-3043-a783-e81de1d5a835
  4 5d0d8aac-bc44-3379-aa7d-9862a381ed2c
  5 c795676e-377d-64ed-8ee4-dd08e0d68a0e
  6 4a5b9c9b-8670-1a70-ba92-c31967704adb
  7 15ea0672-8997-14e5-9edc-dde57e55a03f
  8 168217d0-2562-0425-9347-387a23d699d9
  9 0a4b0713-a447-4e76-ba81-1771c06d56e3
 10 215277a0-2e57-0732-9352-5bac4a52ece0

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 7433611040. Exactly this sequence comes out of new Random(360).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 16 of Run 3 (seed 1,063,142,882): new Random(1063142882), Next(8,24) per post. The RNG predicts N = 10; the post has N = 10 ✓. 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

Related