201206302251 vv2r5

explained decrypted filler

seed 540

Metadata

Post ID: vv2r5
Title: 201206302251 → 2012-06-30 22:51 on A858's clock
Posted (UTC): 2012-07-01 02:49:48
Timezone: UTC−4 · title 22:51 against posted 02:49 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,296 hex characters · 648 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
GUIDs: 20
Filler GUID seed: new Random(540).Next(9) ✓ verified
Run: Probable run 1 (seed 293,378,646) (probable)
Draw: 4 · predicted N = 20 ✓
Machine boot: F 2012-05-15 19:11–19:12 (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: probable

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,296 hex characters = 648 bytes = 81 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 20 GUIDs as hex (shown below).

Decrypted: GUID list

  1 19eb6260-b357-7e06-8729-26ff669464b5
  2 aa522f35-2376-2094-b789-b106f6bde52d
  3 f4fab30a-3395-1ab9-bab6-0fb715c1813d
  4 42bedae1-d610-7765-929c-965323952eb0
  5 0708431f-1e59-036c-9a34-296c7bee4759
  6 d1a4d657-d3da-4cce-bf96-3db92bcb46c3
  7 9d8e059e-9e6f-7748-846e-d34bce966d8f
  8 d5ae3aba-bff2-30e7-9a38-f2bd31ed2d28
  9 7a440bee-1717-7471-b1b0-de1115f8697a
 10 41d992f0-a529-31ae-9300-2e2175810fa7
 11 711fc4a2-7b7e-1a1f-88b3-7418993e7d76
 12 76872854-27cd-0666-abe9-09a56ff2d117
 13 35ffec87-dc62-7d4d-86a4-da85364f8c4e
 14 c9ecaf23-2f27-3306-adab-16b2b74b9913
 15 3bcd5565-273f-884a-9220-07045ce38e65
 16 cd4e9b0f-2dc0-22f2-911e-2208abc3afb0
 17 ad1b7766-4cf9-76c0-9c56-681df09b69e0
 18 52514810-2366-7018-bcaf-5972da1161c4
 19 55207daf-a6b4-2523-8e42-10a326f24e4d
 20 4863e75b-75a0-3b42-a2da-ee2601c92015

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 72170473731073827723. Exactly this sequence comes out of new Random(540).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 4 of Probable run 1 (seed 293,378,646): new Random(293378646), Next(8,64) per post. The RNG predicts N = 20; the post has N = 20 ✓. The seed is the machine's uptime in ms when the app started (boot F 2012-05-15 19:11–19:12).
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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