201208281625 yzahp

explained decrypted filler

seed 43

Metadata

Post ID: yzahp
Title: 201208281625 → 2012-08-28 16:25 on A858's clock
Posted (UTC): 2012-08-28 20:25:00
Timezone: UTC−4 · title 16:25 against posted 20:25 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,424 hex characters · 712 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201208281625) = 6b52f6f136ecf8a5bd1318a9970ed30b (name+title)
GUIDs: 22
Filler GUID seed: new Random(43).Next(9) ✓ verified
Run: Run 26 (seed 1,159,248,375) (seed)
Draw: 0 · predicted N = 22 ✓
Machine boot: 2012-08-15 10:21–10:24 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 3 · 1
Tags: automated (decryptable)2012Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,424 hex characters = 712 bytes = 89 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201208281625 (name+title). Key = MD5(password) = 6b52f6f136ecf8a5bd1318a9970ed30b, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 22 GUIDs as hex (shown below).

Decrypted: GUID list

  1 e31abaea-e2f7-1ef2-b260-2cb95f720ba4
  2 c2440253-14f0-3cd4-9c2f-7344088c25ae
  3 e3ac00d7-8801-710e-bf64-eb9952df3195
  4 7f958058-6149-6a4b-82e4-cd849b228729
  5 c93f4e32-591b-5707-9f3f-94476d1e292b
  6 e342b927-9699-1752-9a89-049b02b617e9
  7 a4aea870-a38b-15d6-8cee-6bce1ddb6ba4
  8 cee59362-c42b-0136-b867-620d1b722fd6
  9 8d4c6bc1-5ae5-2374-b9ed-ec320690b481
 10 cdacbcd4-7515-10bf-8e18-07c3a53fce22
 11 f6f5b562-593b-86b5-a07a-dc6b87fffc13
 12 35ba5d93-587c-0362-86cc-56ed2c1f8af9
 13 54dfe6f2-a5f7-1376-9c93-5dae24676c90
 14 fffb7cb9-a53e-7aff-b589-f864c0bc87c9
 15 32ee6b4e-5d9d-0d3b-be15-86037b440e64
 16 c3686ec3-09d4-7521-bf2e-0aea7a20b1c9
 17 465f373e-3df1-8d18-bdaa-8af8d3ed91df
 18 8e2143b7-c58a-5cd4-a225-0c62c6efacb6
 19 ec2e2472-7e35-706e-a54d-2455bd533b5c
 20 24bb46bc-208b-862a-8ec3-b7a449ee1390
 21 3d1f9781-8ff4-4296-87a4-52882eaa178a
 22 9ec42a3b-81f5-33a6-af08-4f3066fcfc27

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 1376511021801707857843. Exactly this sequence comes out of new Random(43).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 0 of Run 26 (seed 1,159,248,375): new Random(1159248375), Next(8,64) per post. The RNG predicts N = 22; the post has N = 22 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-08-15 10:21–10:24).
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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