201309011559 1lihbj

explained decrypted filler

seed 314

Metadata

Post ID: 1lihbj
Title: 201309011559 → 2013-09-01 15:59 on A858's clock
Posted (UTC): 2013-09-01 11:59:58
Timezone: UTC+4 · title 15:59 against posted 11:59 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 272 hex characters · 136 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201309011559) = d626be9a05eff9e5fc173a9ec02ce4bf (name+title)
GUIDs: 4
Filler GUID seed: new Random(314).Next(9) ✓ verified
Run: Run 52 (seed 1,430,705,843) (seed)
Draw: 13 · predicted N = 4 ✓
Machine boot: 2013-08-14 07:34–10:34 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 3 · 0
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

A85EBC1EEFC3D67B 12E081AB3D9A927D DACA20B1840C3FB0 8D68C8A4FA91DD98 8DFBA7A5AA3D76F5 9BC542D5723E9746 158D2B153C901693 43735502AA566066 07F4DDB6FF97D7F2 FABECEC6B4B44464 406F7B6EAAA49430 D43328951B25C86E BFF7A441410268CE F43B84C07484E783 230724C11248E8E1 F3CC951410B26F4B C9BC18DC0DA9FAE4

Read the ciphertext. Strip whitespace: 272 hex characters = 136 bytes = 17 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309011559 (name+title). Key = MD5(password) = d626be9a05eff9e5fc173a9ec02ce4bf, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 4 GUIDs as hex (shown below).

Decrypted: GUID list

  1 a47a5edc-c547-6084-8517-febe20598ff6
  2 db01366f-ea5e-8263-96f0-0cd11a1c825d
  3 e7c446ba-eb1e-2f30-bd7b-d441b7f277be
  4 45fc1622-6edc-531e-bfee-4cff68aba507

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 6825. Exactly this sequence comes out of new Random(314).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 13 of Run 52 (seed 1,430,705,843): new Random(1430705843), 4·Next(1,12) per post. The RNG predicts N = 4; the post has N = 4 ✓. The seed is the machine's uptime in ms when the app started (boot 2013-08-14 07:34–10:34).
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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