tomkol's strange crackme 1
| Download strange_eng.zip, 7 kb (password: crackmes.de) Browse contents of strange_eng.zip name/serial (tricks)
Difficulty: 6 - Hard, for very professionals only | RatingWaiting for at least 3 votes View profile of tomkol » |
Solutions
Solution by redoC, published 07. sep, 2010; download (33 kb), password: crackmes.de or browse.
redoC has not rated this crackme yet.
Discussion and comments
| redoC 26. Aug 2010 | In the description it is promised that "Everything is reversable." But I think it's not. Here is algo which should be reversed. If anyone known how pls send PM. void HashASM() { #define FILEDATA 0x34333231 // any 4 bytes number, should be determined by reversing the algo char szDate[16]={0}; SYSTEMTIME systime; GetLocalTime (&systime); wsprintf (szDate, "%02u-%02u-%u", systime.wDay, systime.wMonth, systime.wYear); __asm{ MOV EAX, FILEDATA XOR ECX,ECX MOV CL, 0x0C // cycle counter MOV EBX, EAX LEA ESI, dword ptr [szDate] loop_adr: BSWAP EBX XOR EAX,EBX ADD AX,BX XOR AH,BL XOR AL,BH XCHG AX,BX BSWAP EBX ROL EBX,CL ADD EAX,EBX RCL EAX, 0x10 SUB EAX,EBX BSWAP EBX XOR AX,WORD PTR DS:[ESI+3] // month RCR EAX,CL XOR EBX, 0xB2A916C4 SUB EAX, 0xB2A916C4 ROR EBX, 0x0C ROR EAX,CL ADD EAX,EBX XOR EAX, 0xB2A916C4 SUB EBX, 0xB2A916C4 XCHG AX,BX BSWAP EBX ADD EBX,DWORD PTR DS:[ESI+6] // year RCR EBX,CL XOR EAX,EBX SUB AX,WORD PTR DS:[ESI] // day ADD AL,CL SUB AH,CL ROR EAX,CL ADD EAX, 0xB2A916C4 XOR EAX,EBX RCL EBX,CL ADD EAX,EBX XOR EAX,EBX LOOP loop_adr } // EAX = some known value // we should determine FILEDATA by reversing the algo if we know final value of EAX } |
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| Coderess 26. Aug 2010 | Everything is bruteforceble :) |
| redoC 26. Aug 2010 | Yes I probably go that way. |
| tomkol Author 27. Aug 2010 | I still have solution written by goolum that was posted here before. But it's missing. Maybe some mod deleted it for some reason. If mods will accept it i can send it back. |
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