201206261140 vn4km
explained decrypted filler
3DES(name) ECB, 13 GUIDs, seed 406
From the post to its content
As posted (encrypted)
7C6D9EC107D04C80 48545AC0E8776C83 763C940537B54CF9 421FD0831055506C DF82FE9F853DD8B2 AD575994B82B3AF8 EB0444A6BEFA48AB A83A1C5CD6E6C144 1E5092A485F4EF28 A1A5111EF52E51D8 A3A7393D4794493F 32D5E6F3D6DD542F 4D0341C70965D811 7085B1153D2909B6 93D9BFEBA502F6B1 98BA950769FA0ADB F5DEF0E55826653C C74C427677DDB56E ED64688826772641 48006D7A48450DE3 D41CDFE59657F3C7 118E7A94E42D1971 6375F71167DCB2E6 7861F1B7BA5BC4D7 708B463C193360D0 C00091CB2EFDB3FE 6DC1F9B250EE7EB8 E07C41388625EAD8 D9C178871389C169 95595E744AE5BD7C 1B5E2FB15011B18A 3760CB77D752D325 0BDD00C526816B68 8A5D8F4436769CEA 0ED01F7455479307 53F47AC0A2778CDA BE64367D34C52A91 73BC73E5FD2213E5 4BC899005D91EE1E AA251349F08FC702 29CE78A714F23C0F 75732CBBC4C7577D 48235D03033E1543 BBE5DCA49193C94C 69205704A52788EF 92CA159C9741B574 4EBBF2DE3E3C0E73 4CB3B51B427DCD42 552D8FE22E5E27B7 C5C5DCA99F0924D8 8EAD7BC9C4B55DE5 3F06AC088ED92E08 5DACFFBA8FF64DBD
- 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 5e733859-45cb-7b8c-8f7d-aa1cc349d638 2 a9a1740b-84df-8336-8c92-84b45508ee89 3 73607c16-e92e-5bb9-b603-4129e6bfac31 4 075814bd-aa42-182d-918c-b5a3a0875178 5 00cb5111-774a-4379-8e01-ead7ebeb7f26 6 f419b91b-4f6f-3a08-b977-4458f9e75fd5 7 0d1bc2a3-dac0-7428-9260-abaa7858e001 8 027516f4-00f6-142d-8110-ce08b862eb11 9 ed2ce426-29ca-1d28-ac4a-dc69721604a5 10 c4ac3b9a-40d7-83c8-9c8c-feb26d4df197 11 a501e6cc-7da8-323a-9185-2e099c54bac1 12 a629f71a-6eda-3179-a848-142bf299b3fb 13 8bdd7732-a21c-613e-9fb7-6a9bdeee5aae
Explanation
- Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives
7851437118336. Exactly this sequence comes out ofnew Random(406).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 46 of Run 3 (seed 1,063,142,882):
new Random(1063142882), 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 2012-06-14 10:25–10:26). - Conclusion. Filler. The content is fully explained by the two RNGs.