201210080805 114u1a

explained decrypted filler

seed 42

Metadata

Post ID: 114u1a
Title: 201210080805 → 2012-10-08 08:05 on A858's clock
Posted (UTC): 2012-10-08 12:05:58
Timezone: UTC−4 · title 08:05 against posted 12:05 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,040 hex characters · 520 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210080805) = 5beccd2e989c4cbdbd412a5f17ce9688 (name+title)
GUIDs: 16
Filler GUID seed: new Random(42).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 444 · predicted N = 16 ✓
Machine boot: 2012-09-22 10:16–10:36 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 5 · 0
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: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210080805 (name+title). Key = MD5(password) = 5beccd2e989c4cbdbd412a5f17ce9688, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 16 GUIDs as hex (shown below).

Decrypted: GUID list

  1 df91da79-0b52-6472-b8e8-ed2cec55f7b2
  2 a18a24b6-c878-1aaa-b5b6-8ff596b1676e
  3 8d4ab36f-0175-14b7-8601-a716f7043f50
  4 601ea2db-6d9c-441e-872d-8bb02412bfd5
  5 1215c2e6-6b45-1373-a968-c864e8a82e69
  6 98fbd55e-2375-2a4c-b6d9-34fdf53d58d2
  7 fdf9668a-2843-6754-afed-6df00902c3a9
  8 4dbbaa51-737f-4b25-aa61-3b8a7dc21d01
  9 b6ce2ca3-d50d-19e2-a2ec-ad3a1132f540
 10 de0239fa-53ed-685e-8727-dd9cc0404cb5
 11 96fccc1f-37c1-2458-bd85-98ac8aaed6a0
 12 f1aa7d12-6716-2249-a1d5-cc6ce5a50ceb
 13 cc4dae0a-bd64-4437-8aef-347020cdc381
 14 c5adc64e-41e1-2e6b-a2a6-5ddda7e61bfc
 15 1a99953a-1617-360b-92e4-cbaf93c5496d
 16 f03c88b0-fbe6-2269-a0ef-875c9c8b7629

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 6114126416224232. Exactly this sequence comes out of new Random(42).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 444 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 16; the post has N = 16 ✓. 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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