format PE GUI 4.0

include 'WIN32AX.INC'

section '.data' data readable writeable

junk dd ?
time SYSTEMTIME
timedec rb 20
nullbyte rb 0

section '.text' code readable executable

entry main

proc main

     push 10
     call random
     invoke MessageBox,0,timedec,timedec,MB_OK
     ret

endp

proc random ecx

     invoke GetSystemTime,time      ;get current system time.
     xor eax,eax                    ;zeroing eax for some reasons.
     mov ax,[time.wMilliseconds]    ;saving milliseconds in AX register.
     push eax                       ;saving eax value in stack.
     invoke GetSystemTime,time      ;getting another system time after some millseconds.
     xor eax,eax                    ;zeroing eax again.
     mov ax,[time.wMilliseconds]    ;saving milliseconds in AX register.
     pop edx                        ;poping first milliseconds in edx register
     mul eax                        ;multiplying them.
     mov edi,timedec                ;moving buffer here for conversation (not using here)
     mov ebx,[ecx]                  ;moving in ebx 1 argument (for division)
     xor edx,edx                    ;zeroing edx.
     div ebx                        ;dividing edx:eax to ebx.
     ;add dl,0x30                   ;nothing special here.
     ;mov byte[edi],dl              ;-- --------------------
     ret

endp

section '.idata' import data readable

library kernel32,'kernel32.dll',user32,'user32.dll'

include 'API\USER32.INC'
include 'API\KERNEL32.INC'

section '.reloc' fixups data discardable    

proc rand uses ebx,store,length
       local   context:DWORD
   invoke  CryptAcquireContext,addr context,NULL,NULL,PROV_RSA_FULL,CRYPT_VERIFYCONTEXT
        test    eax,eax
     jz      .done
       invoke  CryptGenRandom,[context],[length],[store]
   test    eax,eax
     setz    bl
  invoke  CryptReleaseContext,[context],0
     test    eax,eax
     setz    al
  or      al,bl
       movzx   eax,al
      dec     eax     
    .done:
  ret
endp