201309081859 1lz0zj

explained decrypted filler

seed 843

Metadata

Post ID: 1lz0zj
Title: 201309081859 → 2013-09-08 18:59 on A858's clock
Posted (UTC): 2013-09-08 14:59:50
Timezone: UTC+4 · title 18:59 against posted 14:59 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(A858DE45F56D9BC9201309081859) = 76e000d201ee5cb9f516c8ed76fc9328 (name+title)
GUIDs: 4
Filler GUID seed: new Random(843).Next(9) ✓ verified
Run: Run 52 (seed 1,430,705,843) (seed)
Draw: 70 · 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: 1 · 0
Tags: automated (decryptable)2013Encrypted masked GUID listkey: name+titlerun: seed

From the post to its content

As posted (encrypted)

0E2BAD6942C1F934 F69DA35E110FFE82 15B7747793190386 A5EDB03FF92274D0 DBEC78E62EE42AB1 72008697518C085B 0DB748E9E7DE2722 9E60E41DFC3ACB70 0012900B2322833E 3091F4F076D80F0C DBAF16C8EB9598DA 3007CE098619599D BFE310C011E8F518 685F07C45A06767E E742764DA7F5E74A 149E557C5FCA80EB 2BA5ADCE04D6019D

Read the ciphertext. Strip whitespace: 272 hex characters = 136 bytes = 17 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201309081859 (name+title). Key = MD5(password) = 76e000d201ee5cb9f516c8ed76fc9328, 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 3bab2b6a-0069-1c99-81be-08c50b0c445b
  2 847f8070-18b9-1580-9f66-a6d62573d911
  3 176dd75b-84ae-0b4c-bea6-d2f8d28f30f9
  4 f2fb962a-c068-4161-bf11-adee40ac5814

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 1104. Exactly this sequence comes out of new Random(843).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 70 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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