201210072325 114c0c

explained decrypted filler

3DES(name+title) ECB, 15 GUIDs, seed 600

Metadata

Post ID: 114c0c
Title: 201210072325 → 2012-10-07 23:25 on A858's clock
Posted (UTC): 2012-10-08 03:25:39
Timezone: UTC−4 · title 23:25 against posted 03:25 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 976 hex characters · 488 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210072325) = 39694b6b33e391b3576a17393a12198d (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 15
Filler GUID seed: new Random(600).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 418 · predicted N = 15 ✓
Machine boot: 2012-09-22 10:16–10:36 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 1 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 976 hex characters = 488 bytes = 61 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210072325 (name+title). Key = MD5(password) = 39694b6b33e391b3576a17393a12198d, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 15 GUIDs as hex (shown below).

Decrypted: GUID list

  1 7fd6f29c-65f8-1e2f-8745-6a7e8605faf5
  2 51f5fe68-4c68-71e9-9b5d-e9db34f8ec11
  3 d8ffa41a-5339-121c-8aeb-432249b7fd8f
  4 9b67c784-a33b-56cf-8686-ed184510fbfd
  5 c58d4c62-cadb-0db7-b442-5df26eb90bd1
  6 2c247d7a-f471-8fda-8af7-429b2517305f
  7 df794fb7-8673-6d40-bfb8-7d3f180ca5b1
  8 41cbdc27-dc2e-4239-99b4-f4f86e7d6401
  9 504713d4-401d-1622-9804-8da0a841bd55
 10 3b66aff0-3e64-4f8d-a246-6a0c99bfe874
 11 bcc9a207-c2ec-25e2-8ac0-b87241835aa1
 12 b403e36d-ed4e-84a6-84a7-8f588f70f39f
 13 4053232c-b678-008a-8883-2489e28e6ead
 14 5eec5c70-3118-5145-a3f6-4be6d0227beb
 15 5534d328-d3c0-8843-9f69-bbb791f419c6

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 171508641428058. Exactly this sequence comes out of new Random(600).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 418 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 15; the post has N = 15 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:16–10:36).
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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