solve_iam_so_random.sage

from sock import Sock
from gmpy2 import *
DIGITS=8

def getNum(seed):
	seed = str(seed**2).rjust(DIGITS*2, "0")[DIGITS//2:DIGITS +DIGITS//2]
	return int(seed)
def get_random_number(x):
	arr=divisors(x)
	for i in arr:
		if len(str(i))==8:
			seed1=getNum(i)
			seed2=getNum(x/i)
			result=seed1*seed2
			return (result,seed1,seed2)
while True:
	p=Sock('crypto.2021.chall.actf.co', 21600)
	tmp=p.read_until(b'Would you like to get a random output [r], or guess the next random number [g]? ')
	print(tmp)
	p.sendline('r')
	number=int(p.read_line())
	tmp=p.read_until(b'Would you like to get a random output [r], or guess the next random number [g]? ')
	print(number)
	print(tmp)
	nextnumber,seed1,seed2=get_random_number(number)
	p.send_line('g')
	a=p.recv(1024)
	print(a)
	p.send_line(str(nextnumber))
	result=p.recv(1024)
	print(result)
	if result ==b'Incorrect!\n':
		p.close()
	else:
		print(result)
		print("correct")
		p.send_line(str(getNum(seed1)*getNum(seed2)))
		tmp=p.read_line()
		print(tmp)
		flag=p.read_line()
		print(flag)
		break