201206290024 vsb5p

explained decrypted filler

3DES(name) ECB, 13 GUIDs, seed 768

Metadata

Post ID: vsb5p
Title: 201206290024 → 2012-06-29 00:24 on A858's clock
Posted (UTC): 2012-06-29 07:23:15
Timezone: UTC−7 · title 00:24 against posted 07:23 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(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 13
Filler GUID seed: new Random(768).Next(9) ✓ verified
Run: Run 9 (seed 449,725,219) (seed)
Draw: 18 · predicted N = 13 ✓
Machine boot: F 2012-05-15 19:12–19:12 (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: namerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 848 hex characters = 424 bytes = 53 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 13 GUIDs as hex (shown below).

Decrypted: GUID list

  1 0d786111-0b63-80bc-b32d-22b3c91701d9
  2 fe1cd9cc-31f8-15f5-b3b1-1113b2dbbfd1
  3 073d77ee-f209-50b0-9936-ad2d5b1a9e4e
  4 5cc1e4b2-7e14-4226-8da6-7edb790db083
  5 95b4fc6c-0126-86c8-bfb1-0dfec91bc805
  6 a5deaac2-be53-614a-ab51-a364a1ea3eab
  7 b74ce651-782a-0933-a992-05f492a8f089
  8 a972dfdf-df91-6490-8dda-3c7936ed9934
  9 8097ef8c-b690-8ddb-9d24-a22149d0a97c
 10 b0108985-e6ed-4cb3-af4b-fe3bbdbe7156
 11 74b83945-2bbc-0c96-b65c-c9415765e30c
 12 b3c52b14-4413-0ad1-9c73-2b71abe9edf8
 13 0274afb9-c335-52b2-aa61-39041a795ad4

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 8154860684005. Exactly this sequence comes out of new Random(768).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 18 of Run 9 (seed 449,725,219): new Random(449725219), 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 F 2012-05-15 19:12–19:12).
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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