blaise: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=00fb13e98a303dff4159e894942e363208415ba1, for GNU/Linux 3.2.0, not stripped

$ ./blaise
15

$ ./blaise
19
12
24
a
$

def f(num):
	ret = 1
	counter = 2
	while counter <= num:
		ret *= counter
		counter += 1
	return ret

def c(ran, counter):
	num1 = f(ran)
	num2 = f(counter)
	num3 = f(ran - counter)
	return num1 / (num2 * num3)

from pwn import *
from sys import argv

if argv[1] == "r": 
	p = remote("chall.csivit.com", 30808)
else:
	e = ELF("./blaise")
	p = e.process()


rand = int(p.recvline())  # Recieves random number
log.info(f"random number: {rand}")

def f(num):
	ret = 1
	counter = 2
	while counter <= num:
		ret *= counter
		counter += 1
	return ret

def c(ran, counter):
	num1 = f(ran)
	num2 = f(counter)
	num3 = f(ran - counter)
	return num1 / (num2 * num3)

for i in range(0, rand + 1):
	data = int(c(rand, i))  # Gets required number
	p.sendline(str(data))   # Sends
	flag = p.clean()
	if flag:  # I was lazy :p
		log.info(f"flag is: {flag.decode()}")
		exit()

int main(void)
{
  int random;
  time_t tVar1;
  long result;
  long input;
  time_t local_40;
  time_t local_38;
  time_t local_30;
  long number2;
  long number1;
  char *time_to_execute;
  int counter;
  int check;
  
  setbuf(stdin,(char *)0x0);
  setbuf(stdout,(char *)0x0);
  setbuf(stderr,(char *)0x0);
  tVar1 = time(&local_30);
  srand((uint)tVar1);
  time(&local_38);
  check = 1;
  counter = 0;
  while( true ) {
    random = rand();
    if (random % 3 + 4 < counter) break;
    random = rand();
    number1 = (long)(random % 10 + 6);
    random = rand();
    number2 = (long)(random % 10 + 6);
    printf("%d %d\n",number1,number2);
    __isoc99_scanf(&DAT_0040200f,&input);
    result = function1(number1,number2);
    result = function2(result + 3);
    if (result != input) {
      check = 0;
    }
    counter = counter + 1;
  }
  time(&local_40);
  time_to_execute = (char *)(double)(local_40 - local_38);
  printf(time_to_execute,"fun() took %f seconds to execute \n");
  if ((check != 1) || (30.00000000 < (double)time_to_execute)) {
    printf("Nahh.");
  }
  else {
    puts("Hey, you got me!");
    system("cat flag.txt");
  }
  return 0;
}

number1 = (long) (random % 10 + 6);
random = rand();
number2 = (long) (random % 10 + 6);
printf("%d %d\n", number1, number2);
__isoc99_scanf(&DAT_0040200f, &input);
result = function1(number1, number2);
result = function2(result + 3);
if (result != input) {
    check = 0;
}

if ((check != 1) || (30.00000000 < (double)time_to_execute)) {
    printf("Nahh.");
}
else {
    puts("Hey, you got me!");
    system("cat flag.txt");
}

long function1(long num1,long num2)

{
  int counter;
  int answer;
  
  answer = 0;
  counter = 1;
  while ((counter <= num1 || (counter <= num2))) {
    if ((num1 % (long) counter == 0) && (num2 % (long) counter == 0)) {
      answer = counter;
    }
    counter = counter + 1;
  }
  return (long)answer;
}

long function2(long number)
{
  long lVar1;
  
  if (number == 0) {
    lVar1 = 1;
  }
  else {
    lVar1 = function2(number - 1);
    lVar1 = lVar1 * number;
  }
  return lVar1;
}

def function2(number):
    if number == 0:
        return 1
    
    return number * function(number - 1)

two numbers -> highest common factor -> +3 -> factorial -> compared to input

from pwn import *
from numpy import gcd
import numpy

p = remote('chall.csivit.com', 30827)

while True:
    try:
        num1, num2 = map(int, p.recvline().decode().split()) # Cast and assign the two numbers
        log.info(f'{num1} {num2}')
    
        hcf = gcd(num1, num2)
        log.success(f'HCF of {num1} and {num2} is {hcf}')

        fact = numpy.math.factorial(hcf + 3)
        log.success(f'Factorial of {hcf + 3}: {fact}')
    
        p.sendline(f'{fact}')
    except ValueError:
        # If it's ValueError it can't be cast to an int, so we've received the flag
        break

print(p.clean(1).decode())