201207271434 x9oh7
explained decrypted filler
3DES(name+name) ECB, 19 GUIDs, seed 688
From the post to its content
As posted (encrypted)
7686795BEA30AD88 77BE128ED08B7FFD 83736DFE0C4F4D81 914F94419E23C190 AA22E496E7380992 9FFD30D7EA24B51D AEF85DA112DE8730 2897767260081352 E34E3343B28495F9 065ED813148F16F5 1D793496E0A72AE3 C57DE4D16687CD55 E9B56D765060D055 3E1C2AD0C827C814 DD2A8C655314EC85 8025704ABD946C5C 88B981EE00D48629 11FC52F83D2AB4FD 0244F1D399E23003 EB5A7A4AAA154353 4A22DB5B3CF99EF6 04021FF39AFA1326 05882526F5920931 DEB7E4901D87366A 52B7E21A7D4F840B A04F4FF0215D50F0 023F266AEAB0242B 46BE3FABE205329D BB49A70B2C4763EF 7C0F8B4233EEB891 5C3D84ADFDAD8E2B 2547F6E68E5F8ED8 25A003DA1F60E93A EDD14D30A843D724 9178B568B17DDED4 FBF6D534AB2FF539 FE5DBC9370FEFE86 D4F7EF7BA707A5A5 FF0F43D9277F1D68 F92A5F9E076853F9 75750538CE8FF163 7290A1BCF6AB8797 F06AC50F6E58DD97 31D46ED5DF71E880 8094B4F8C2781893 E4064A81794428C6 2A33FF9F158D3EDB D8DB7646A4C1047C 80BABDE7618066BC 0742457BA67F9C41 00EF2166B51CC539 42573CBB0FD8A0B5 868BEABDBC549861 9B4D50B69125B02D 1F10CE93362915F3 F68D0BD26CBD8DAA 22A765345DC8F4C3 06059AB4AB74D8C3 60D746A82348CC6C B7F721B547D7CA36 A55DD54068E73C5C AEB6FCCA0F514631 029175C24C50A7F9 F48044065B007D90 F5161C44EBDF3F29 40C41E43C543C00F 3C192793A56A1E07 E16F49A95A0D0D74 619B3DA3822F9A4B 0B22789A256B6573 FFB3A4AF9E0C5EB6 8CDF53F9204974D7 AE2496448BBDFBB6 DA4BBB46311B70E2 2153F2FAC764CA1B 7B96D0DD53976D04 12ECFFDF2899BD4C
- Read the ciphertext. Strip whitespace: 1,232 hex characters = 616 bytes = 77 8-byte 3DES blocks.
- Derive the key. Password =
A858DE45F56D9BC9A858DE45F56D9BC9(name+name). Key = MD5(password) =0dcc4bd9e114ebc42078977dc9125404, used as a two-key 3DES key. - Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 19 GUIDs as hex (shown below).
Decrypted: GUID list
1 c7371443-a632-1006-91ec-203eb3a31247 2 71c182ca-015f-6674-b567-908c1e487678 3 c3e5c0df-a726-63ac-a638-909e81e1091f 4 a4da730f-aee7-356b-965f-d70594b3ed0d 5 3758d5a5-3961-7328-bab6-f2259b84ecf3 6 00f63bd4-0569-7f68-a843-66f6f0d3e701 7 ab0a1ae6-3034-144f-88a7-5c308e312b30 8 95d77853-86ab-5597-8661-9624f75cdeff 9 fa050457-9c3a-0607-ab8b-a89bc670ffd6 10 855ddb77-803b-8aa1-b8a7-9887f35b1c42 11 2530d825-5d4a-1864-aa07-bb13acb14245 12 97303117-c34e-5d7a-b3a3-0cbbc6b53e0b 13 d2944e77-d33f-534b-bb2b-1ff080873b79 14 19311074-cda1-34ca-bc5c-a964261f73d6 15 296e7205-4686-5ee2-b557-d59a018844e4 16 5577d4b5-33cb-6cc4-a82e-4626c599a86f 17 da14872b-1b2b-0172-a4fe-a2973183a848 18 5b3364f2-097d-4653-93bb-10d2a3430fc2 19 34377115-90c4-2890-9c20-cb9fde8107a7
Explanation
- Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives
1663771508155356042. Exactly this sequence comes out ofnew Random(688).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 34 of Run 18 (seed 6,051,781):
new Random(6051781), Next(8,64) per post. The RNG predicts N = 19; the post has N = 19 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-07-27 19:15–19:16). - Conclusion. Filler. The content is fully explained by the two RNGs.