201206290023 vsb4r
explained decrypted filler
3DES(name) ECB, 17 GUIDs, seed 954
From the post to its content
As posted (encrypted)
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
- Read the ciphertext. Strip whitespace: 1,104 hex characters = 552 bytes = 69 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 17 GUIDs as hex (shown below).
Decrypted: GUID list
1 1a8efdcd-8653-1b85-8826-7d1077c5cfe0 2 ce4c4bf9-56bf-6c63-bc5e-773c0f17920b 3 62d184dd-be4d-5d3d-ae59-c7749bd53fba 4 6de68b93-4927-1760-96d6-7b6117924846 5 8ae31d3a-e4a9-85b2-a58d-0b744dae3621 6 74cbba3e-511b-26f6-99b7-bcd3caa84396 7 1bbf7b4a-08dc-3a8f-aa69-62326cc38713 8 3380d9c8-0894-048e-a5f9-00acf9286b0e 9 8d00614d-1c85-089d-9f0a-bf4a7e79000b 10 42926c9e-a26d-01c2-a7c8-b9ad94cea7de 11 ef003e2a-c44d-1cea-b211-b664a7118440 12 6ba69c2a-6f74-2024-a9f6-66efeff8bb04 13 11ef0b90-a034-45ef-b836-d6fb98a2e09c 14 39464d77-e49f-7078-a96a-ea9ec6269b8e 15 3c83199e-5b74-6028-aa23-03e00d8e6287 16 49a51b05-10f7-7dac-9224-7ef21668e1ad 17 365b9d55-8715-7de2-a9f7-19b28acc4c9e
Explanation
- Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives
16518230001247677. Exactly this sequence comes out ofnew Random(954).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 8 of Run 9 (seed 449,725,219):
new Random(449725219), Next(8,64) per post. The RNG predicts N = 17; the post has N = 17 ✓. 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.