201309131959 1mckee

explained decrypted filler

seed None

Metadata

Post ID: 1mckee
Title: 201309131959 → 2013-09-13 19:59 on A858's clock
Posted (UTC): 2013-09-13 23:59:59
Timezone: UTC−4 · title 19:59 against posted 23:59 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(A858DE45F56D9BC9201309131959) = 8cf782b731f834021f5e08552199dcdb (name+title)
GUIDs: 4
Filler GUID seed: ambiguous: 310, 446
Run: Run 53 (seed 26,950,390) (seed)
Draw: 31 · predicted N = 4 ✓
Machine boot: 2013-09-12 09:30–10:30 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 2 · 0
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

12E8E14CFBEAB260 8345D313806E9EDE D5606510B77574BD 00AAB88C0CB3BFD9 DAA315009AF59CC6 DBECC85D61DDD6FD 8241DC45FC4778E2 A2656B806B0D5C10 5417E5877CD86850 D036B9110FC8B418 0D3A28C8E8C636D6 A4705048664F9E39 5BA83CFD03F556C8 C507E6DDDD742361 79BA4F378EC83834 EBA851979F7F7124 0E2E54A205CA6EA1

Read the ciphertext. Strip whitespace: 272 hex characters = 136 bytes = 17 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309131959 (name+title). Key = MD5(password) = 8cf782b731f834021f5e08552199dcdb, 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 99e0053e-5dbb-6783-80cf-b4bda44f95ed
  2 84d72d45-a023-663a-bd92-9417417fe5d5
  3 07036aa9-4a82-4f8b-afcd-9273e5e58eb1
  4 9f91d262-8daf-63b0-b7ed-c2dfa37eb3e9

Explanation

Explain the mask digits. The mask digits 6646 fit several seeds (310, 446); too few GUIDs to pick one.
Explain the count. This post is draw 31 of Run 53 (seed 26,950,390): new Random(26950390), 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 2013-09-12 09:30–10:30).
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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