201206270915 vnswa
explained decrypted filler
3DES(name) ECB, 13 GUIDs, seed 650
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 968d9504-0cbe-22f6-b838-b3dacd52e7c4 2 3e6d432c-be14-401b-a243-f94337b15469 3 efe8f08f-e224-00c5-9ec4-98658ef739f0 4 0b9aa4aa-fea1-27ab-a564-877ec24fdd09 5 fe2319db-df41-6fe1-a165-db6419e5fa76 6 c6a8c58f-d91e-5256-9d09-f7a53e8815af 7 833fb4e8-fc25-13d8-b8c8-7110f62f08a9 8 6924bcd0-d725-417d-8431-6ccaed183f45 9 c1103a0c-717f-329c-b5d1-acbe63f4ea63 10 33cd8b85-9f56-818d-b14d-9c393777830b 11 69afa4a2-142d-1f9f-8ec1-b00835d7ddda 12 96f0d1f0-cf31-885a-b3d1-158415f8ddc1 13 c0271455-5264-4ac7-8a46-555a4ccc0d54
Explanation
- Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives
2402651438184. Exactly this sequence comes out ofnew Random(650).Next(9): the per-post millisecond seed of the mask generator. The other 30 hex digits of each GUID areGuid.NewGuid()output and carry no message. - Explain the count. This post is draw 17 of Run 6 (seed 652,173,660):
new Random(652173660), Next(8,24) 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 19:06–19:16). - Conclusion. Filler. The content is fully explained by the two RNGs.