201206270524 vnfgj

explained decrypted filler

3DES(name) ECB, 16 GUIDs, seed 366

Metadata

Post ID: vnfgj
Title: 201206270524 → 2012-06-27 05:24 on A858's clock
Posted (UTC): 2012-06-26 21:22:51
Timezone: UTC+8 · title 05:24 against posted 21:22 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(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 16
Filler GUID seed: new Random(366).Next(9) ✓ verified
Run: Run 5 (seed 659,062,118) (seed)
Draw: 7 · predicted N = 16 ✓
Machine boot: F 2012-05-15 19:11–19:13 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 2 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: namerun: seed

From the post to its content

As posted (encrypted)

BFF9A49A698E9859 051B872E8699D4CE C2FC2E271C4B8DA7 B7668365F4E337AB C4281A7E8EB73E16 1BFEDA0CFAE61D73 E7FD690516641ADB CEC2145D6F3ACBF5 EFD817F181472C6C FB37A32445BED578 FF6CE2CFEEBAA6FF D1952D93DBDE558A EBD416B7F8B9F83C BFC7D9C9DE97F130 4E8449487F08C841 627FF2824D2A9F98 AB7F05189D4F123F EB0CA07F93C3EF74 C4C3774D2A45BD60 F9DA9D492ACDAA69 4D073F1D616C8D66 9B56E0B41BD174E3 BB3B357483780CA9 8A0F1D6AC6A757DD 7FCA3968D44A6325 157666FF9DBE4ED6 CECED5A4F9C9349F 92C43D730339275B 129455103632F363 2264E156589CA01E 68D09E7E18C20012 E4F58BC5DF3D8492 A891C8EF9568E315 85BEA34354FBD712 54599FA7897DA8F8 879AD07BFC8C1CF5 EC8584EC5F7D200C B04D92112F527423 07678789C1740833 D6236ECD53D75771 4C851D48BF9848B8 7DEC7758B5947819 46640C3337D5B041 C7B5D1E031508296 C774BAE10B0FDEC2 1E2B1838817742F9 0680F1DC5BF66BCD DC06BAE84EF83889 ECAC354EBF117060 B68F60A31BB0996B ABFE8C7C99F223D1 2D999556C40B5B94 95403BFEDDE5F8F7 6F6887B8C979806C D4A9A34950211B9E 54BC65275D2CB3E4 B9EFBB8730DF78B4 DCC8B4CE440D8FE7 5E7C062646364D8C 7FF4A9626D7E7847 3CEA449AC2EC556E 34ABB885BE11FBCB C4046CE9B29F050B E3CE19CDD5C2A062 5DACFFBA8FF64DBD

Read the ciphertext. Strip whitespace: 1,040 hex characters = 520 bytes = 65 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9 (name). Key = MD5(password) = 34a14a42e98ff96095af56604e290cae, 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 c1e6c65f-2b97-862b-8657-19ba7d0db3dd
  2 aa305d35-f0b5-14d4-a917-0a9c5762cf70
  3 9051dbdf-6421-5674-8906-2dbd0908e433
  4 847769c5-8ef8-6886-b8c8-b703d1e2c407
  5 9f3fe636-7469-4ca5-ac82-3525f0bf719b
  6 55e21eef-70bb-3c81-9c54-d1243c95f232
  7 c03e4e9a-66fc-85b6-8919-8dff91348a0f
  8 544c1f19-65d8-04df-a27c-ae877751037a
  9 d1623eef-b976-2d09-a6e9-720a455bb864
 10 db406f28-6e65-2982-a8b0-dd05f70f0b33
 11 a0c79208-dcbf-8e8a-be94-4bf10af26f3b
 12 4eab8bce-9e74-1581-b33e-981fb68eb012
 13 a71351de-be1d-2c15-ac2a-181f561b621d
 14 d989136f-bbe5-772b-bba0-49065007fe8b
 15 491f9e7b-433d-1404-b8ac-c71d868130a6
 16 5720f0ce-26c7-51d7-8656-5cbfe426b5f1

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 8156438022812715. Exactly this sequence comes out of new Random(366).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 7 of Run 5 (seed 659,062,118): new Random(659062118), Next(8,24) 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 F 2012-05-15 19:11–19:13).
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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