Reversing : The Hacker's Guide to Reverse Engineering

00402300 SUB ESP,24

00402303 MOV EAX,DS:[405020]

00402308 PUSH EDI

00402309 MOV EDI,SS:[ESP+2C]

0040230D MOV SS:[ESP+24],EAX

00402311 LEA EAX,SS:[ESP+4]

00402315 PUSH EAX

00402316 PUSH 0

00402318 PUSH 0

0040231A PUSH 8004

0040231F PUSH EDI

00402320 CALL DS:[<&ADVAPI32.CryptCreateHash>]

00402326 TEST EAX,EAX

00402328 JE cryptex.004023CA

0040232E MOV EDX,SS:[ESP+30]

00402332 MOV EAX,EDX

00402334 PUSH ESI

00402335 LEA ESI,DS:[EAX+1]

00402338 MOV CL,DS:[EAX]

0040233A ADD EAX,1

0040233D TEST CL,CL

0040233F JNZ SHORT cryptex.00402338

00402341 MOV ECX,SS:[ESP+8]

00402345 PUSH 0

00402347 SUB EAX,ESI

00402349 PUSH EAX

0040234A PUSH EDX

0040234B PUSH ECX

0040234C CALL DS:[<&ADVAPI32.CryptHashData>]

00402352 TEST EAX,EAX

00402354 POP ESI

00402355 JE SHORT cryptex.004023BF

00402357 XOR EAX,EAX

00402359 MOV SS:[ESP+11],EAX

0040235D MOV SS:[ESP+15],EAX

00402361 MOV SS:[ESP+19],EAX

00402365 MOV SS:[ESP+1D],EAX

00402369 MOV SS:[ESP+21],AX

0040236E LEA ECX,SS:[ESP+C]

00402372 LEA EDX,SS:[ESP+10]

00402376 MOV SS:[ESP+23],AL

0040237A MOV BYTE PTR SS:[ESP+10],0

0040237F MOV DWORD PTR SS:[ESP+C],14

00402387 PUSH EAX

00402388 MOV EAX,SS:[ESP+8]

0040238C PUSH ECX

0040238D PUSH EDX

0040238E PUSH 2

Listing 6.5 The Cryptex key-generation function.

214 Chapter 6