201309131859 1mcgh3

explained decrypted filler

seed 482

Metadata

Post ID: 1mcgh3
Title: 201309131859 → 2013-09-13 18:59 on A858's clock
Posted (UTC): 2013-09-13 22:59:59
Timezone: UTC−4 · title 18:59 against posted 22:59 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,040 hex characters · 520 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201309131859) = e86c4cd8d312247d8e486dcb4708ba68 (name+title)
GUIDs: 16
Filler GUID seed: new Random(482).Next(9) ✓ verified
Run: Run 53 (seed 26,950,390) (seed)
Draw: 30 · predicted N = 16 ✓
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)

0FE16383FDF8AAAA 76F58D44E4200228 46EE230949C38559 533FB135C993AA28 C9CDD3B17AD70FCD 5316A240FED78166 3B19402AB54B9D3F 3B1B6A75ECB544C9 A23C8F6614E513E9 9BB7AE812E84CD1B F6AF220D89A57E3C 90540FECE910DB81 798F92F140FA8FF2 F78CD5F8E25A54E5 EAA424FEE1F49118 D0D92036EF4881ED BAAF41F6EB59C4F9 E81628214E318A64 9EEFA16F49191D26 015244AC6FA78376 64CB67862C7B3652 E899881DDC20A843 EBE1B125816D4297 9B5A0A7EA42F5550 2BE0AD597221A97F 3D67491DFF0405A4 CC5DFEB274EF1DB8 16B8CDB70CEF3404 5AFAFE38FA78A826 4DE20757448DC53A 28DE513352810716 D9A89BB6D5C2923F B76343A00872E236 32332F707F5D0C81 BEA7BD9384AF568C 6D619866C12115EE 79AB50AE295B5C14 42A5C2730D36F847 B217D842577E053B 892A78E9736374E9 3025E7FC4DCBD96A C5042B2DC590F35A 93028358149945F7 7D08AB15A68581C9 EA520B5AE204BF95 0A64E7ACCBE6AAA5 EBD9EEC2459D882D 09B99D97989CACC8 8F90B61B47C0C11B C094DCC749C64B8E C86E0FC7A38C2DAD E6EB7E52881BC742 3B3125A2E9FF92A7 297588FEB29D39C7 6C98B640BF83ED06 05E04AAD3C7C345C 6CA51DF70DDF040C C137CF860ACA7CB6 90E8668FF785EAEF 52F90266D45F2ECE 7ADAE0479BBF9062 ECC4E31C30D335F5 A00B447F0B58C577 BAC066CDC9A51058 2A8CEFF397F1E242

Read the ciphertext. Strip whitespace: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309131859 (name+title). Key = MD5(password) = e86c4cd8d312247d8e486dcb4708ba68, 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 c338b7f7-3379-47d3-9680-ba9560f0b3da
  2 c6dddbf3-cba4-28d1-9830-5de56ffe46ae
  3 b8cca3fb-a599-678b-aecb-031daa0f300c
  4 e9ee08ed-9f3b-3570-ab4c-20b336d9ec30
  5 3adc9188-141f-71ab-90df-ad40f878454d
  6 a6854aff-92de-6a92-80ed-958ecfef8722
  7 8a266b22-238b-7a93-89b2-0a90f4bcec31
  8 e21dcbc0-aa88-2ae1-9ae4-d98954a3a4c1
  9 006bc825-60e3-5eae-8afe-e739b0eb4cd0
 10 0b560f6a-4523-0be3-8b22-6e939846cc6c
 11 be4b1ef7-7a38-3369-9e78-f6042aec3f5b
 12 7bd3cb72-a1f2-61c5-bcaf-30bfa6a5046b
 13 edc91599-f7a3-86d1-8374-1190e7f2b706
 14 0ac73b4a-49fd-26f0-a453-11ef99c6195a
 15 ea6b357b-3694-3e7d-a21c-ff656922a118
 16 fac4389b-cd5b-06bf-bda9-de219bb15933

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 4263767250368230. Exactly this sequence comes out of new Random(482).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 30 of Run 53 (seed 26,950,390): new Random(26950390), 4·Next(1,12) 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 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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