201210062324 112n76

explained decrypted filler

3DES(name+title) ECB, 13 GUIDs, seed 127

Metadata

Post ID: 112n76
Title: 201210062324 → 2012-10-06 23:24 on A858's clock
Posted (UTC): 2012-10-07 03:24:44
Timezone: UTC−4 · title 23:24 against posted 03:24 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 848 hex characters · 424 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201210062324) = daaf870ea600910516041014712cb208 (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 13
Filler GUID seed: new Random(127).Next(9) ✓ verified
Run: Run 35 (seed 854,622,578) (seed)
Draw: 346 · predicted N = 13 ✓
Machine boot: 2012-09-22 10:16–10:36 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 3 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+titlerun: seed

From the post to its content

As posted (encrypted)

5BC6CB4240F445F7 0F24AC899AECA2A1 72A8166417F82E34 2066F54BE531A8FA 3004B44E021C0025 0E04CE1F44217CC8 CEABC939FB2204D2 2C13FDE46FBFE940 808568135DB3DB5F 403616036DE1D590 A6050D1321EFE167 E58D4393BBF03A4D 3E8E3AC7C930F416 DCCFAD9C8848FEE8 D439E4F740660D24 4C5E7E80D201372D BF34F1981D01AB8C BC67CCA609A77462 1A1B607140D9A54E 7594731056204507 B81F916D232E081B 9DF3F3E6C1B20918 A6A21FBC67EC9F0C 871C65377B6A5491 BB723E09252B113C DCCFC96F6340D464 A1349F8BD5CECD1A 1729716605646B74 411772997A83CF2E 9BCCF912BCAF1124 C826486E3C8C4414 A9EB896603290F55 C0CC4CABB3121B15 348F02EABAE19F3D 8A63AEF1B58CFA87 C0F2069993EA46C7 5A9C8A0FAB990C86 329B326358DF01D9 DD85F7F5A1E54051 38AFB41472D88336 5950C8F016A73F72 0E25148112A37EA5 E40E75F6F67B974E 6F57EAF085A07128 1FC915D7817204E2 90E7D5470C567B1E 18A360FA46C2B544 1AEF7090B2BAEB14 6B2B67CE39AC4D83 4EE29FE7433E76BA A6EF7363DEFF4807 1DE02BE1AC690A38 8B99C480AAF07D14

Read the ciphertext. Strip whitespace: 848 hex characters = 424 bytes = 53 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201210062324 (name+title). Key = MD5(password) = daaf870ea600910516041014712cb208, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 13 GUIDs as hex (shown below).

Decrypted: GUID list

  1 80b5357c-31a8-03f3-a4c6-76eff162130f
  2 73d1a063-313b-0ef5-831a-6dd505465544
  3 fbb87858-2815-43a0-94dd-93228b94ac02
  4 780fdfa2-6db9-5847-a11b-e8b332b21de8
  5 deccce92-c888-4e73-9031-38f46aaf9f62
  6 4a66c093-2507-4530-a633-02e30584c92b
  7 f8442f7e-b9cc-7c64-a098-345343a2634c
  8 50ec9731-6002-12fb-a727-eb753a777e9f
  9 0f505bd9-f046-6f5a-816f-99102aa4eda6
 10 703006ba-e6e6-0041-b54b-3d61e65f0d41
 11 31ae9484-473e-764f-a0c2-bce1ae22a142
 12 d8638946-784c-5e66-b285-77c48342c0a1
 13 30610a69-eb5d-8396-84b6-c4fcedd733cb

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 0045447160758. Exactly this sequence comes out of new Random(127).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 346 of Run 35 (seed 854,622,578): new Random(854622578), Next(8,64) per post. The RNG predicts N = 13; the post has N = 13 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-09-22 10:16–10:36).
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

Related