201309131759 1mcc9l

explained decrypted filler

seed 570

Metadata

Post ID: 1mcc9l
Title: 201309131759 → 2013-09-13 17:59 on A858's clock
Posted (UTC): 2013-09-13 21:59:59
Timezone: UTC−4 · title 17:59 against posted 21:59 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 528 hex characters · 264 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201309131759) = afa398d240ff1f7a0194afd5584dbebb (name+title)
GUIDs: 8
Filler GUID seed: new Random(570).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 29 · predicted N = 8 ✓
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: 1 · 0
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

A8D96351E7C7369E C4C2BD37AB3B113D 8A94C4A6C9CF4F1A 059F30A23DC88C38 0FF64E3F38109C2C B1BAC0AD1F1052FD 7701D933247B53BD 6698372696B66FD3 60BFD190D0C22691 20BE34E7F7DD8179 F618EC875AA1AD96 B6E8A631767C0035 333D93463C515260 79766396D7E59437 7FBEAA6A79707CE9 D2DB261170E0298A D252ED482DD35B0D F1FC85A1A8021EA6 67DFD551B7C1114F AE880848ABAD764D C4D2C07759E58B00 BD2AB6C9B7309197 E829F532A7D4FD68 283E0832833CD36A 26FCA65B79DA7703 A1C9CE4091C3D6E8 1AFB944C79AE9796 A90E1DF52BCCE23B 29CC29EC71279660 CE37AC5113197F2C EA4262211059BFAF 423A689C4688CE3D 3113233E6C9B915B

Read the ciphertext. Strip whitespace: 528 hex characters = 264 bytes = 33 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309131759 (name+title). Key = MD5(password) = afa398d240ff1f7a0194afd5584dbebb, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 8 GUIDs as hex (shown below).

Decrypted: GUID list

  1 ede9413a-09a5-487a-b345-b26ef3e3e533
  2 7e54d82b-b578-0336-942a-bc3c57c65fa7
  3 11bf0131-4cfa-14ca-a6fd-d7c61a880a27
  4 439e270c-88fb-1fa3-a4fd-31d80278d8c7
  5 7cd68ff9-e16b-48f4-baa0-f3779f4b1e1f
  6 54f1b078-d3c8-6df6-8a91-137af2f62730
  7 4658a73f-4279-24a3-aada-8f963397764d
  8 020329b2-a097-396b-96b4-87f14ee9f4e5

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 40114623. Exactly this sequence comes out of new Random(570).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 29 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) per post. The RNG predicts N = 8; the post has N = 8 ✓. 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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