/*

   randy (bin100) BKPctf

   We get x64 binary which ask for password
   after quick reversing, we can find that it have to be 0x1c long and its passed to
   function called `keygen`  which determin what to print ':)' if ret == 0 or ';(' if not
   keygen is simply bunch (7) calls which looks like that:

   do_1:
.text:0000000000400A2D                 mov     rax, [r13+r12*4+0]
.text:0000000000400A32                 mov     rdi, rax        ; seed
.text:0000000000400A35                 call    _srandom
.text:0000000000400A3A                 call    _random
.text:0000000000400A3F                 cmp     rax, 7358837Ah
.text:0000000000400A45                 jnz     bad
.text:0000000000400A4B                 call    _random
.text:0000000000400A50                 cmp     rax, 6E1B2658h
.text:0000000000400A56                 jnz     bad
.text:0000000000400A5C                 call    _random
.text:0000000000400A61                 cmp     rax, 3C00C5FFh
.text:0000000000400A67                 jnz     bad
.text:0000000000400A6D                 call    _random
.text:0000000000400A72                 cmp     rax, 8C0D4AAh
.text:0000000000400A78                 jnz     bad
.text:0000000000400A7E                 inc     r12

  the seed is taken from input, it split it on 7 4 byte numbers and do abowe
  since result of random is determistic and based od seed passed via srandom
  we reep of first 2 numbers to do some corretnes check and fire up
  brutforcer and after few minutes (or more;])we get our answer:

  n0t s0 r4nd0m0 4ft3r a11!!!!

  --
  mak

 */


#include <stdio.h>
#include <stdlib.h>

int ans[8] = {0,0,0,0,0,0,0,0};
int i=0;
int foo(unsigned int *s,long int r1,long int r2,int n){
  long r=0;
  srandom(*s);
  r += random() == r1;
  r += random() == r2;
  if(r==2) { printf("%d seed%d: %x %s\n", i,n, *s,(char*)s);fflush(stdout);ans[n]=*s; i++;return 1;}
  return 0;
}


void asdf(unsigned int x){
  srandom(x);
  printf("%x\n",random());
  printf("%x\n",random());
  printf("%x\n",random());
  printf("%x\n",random());
  exit(0);
}


int main() {
  int c1,c2,c3,c4;
  char b[4];
  for(c1=0x20;c1<0x7f;c1++){
    for(c2=0x20;c2<0x7f;c2++){
      for(c3=0x20;c3<0x7f;c3++){
	for(c4=0x20;c4<0x7f;c4++){
	  b[0] = c1;b[1]=c2;b[2]=c3;b[3]=c4;
	  if(i==7) { printf("%s\n",(char*)ans);fflush(stdout);exit(0);}
	  if(foo((unsigned int*)b,0x7358837A,0x6E1B2658,0)) continue;
	  if(foo((unsigned int*)b,0x34D8C3B5,0x5B56DCA1,1)) continue;
	  if(foo((unsigned int*)b,0x1F49456C,0x27C0FA1D,2)) continue;
	  if(foo((unsigned int*)b,0x1FEA6614,0x41CDB864,3)) continue;
	  if(foo((unsigned int*)b,0x4E81ABC7,0x792CE075,4)) continue;
	  if(foo((unsigned int*)b,0x683D3F5D,0x0CAAE38D,5)) continue;
	  if(foo((unsigned int*)b,0x28c9a8fe,0x3324b23,6)) continue;
	}
      }
    }
  }
  puts("wrong!");
  return 0;
}