[CSAW 2016] Coinslot

coinslot.py

from pwn import *

r = remote('misc.chal.csaw.io',8000)

# Create an array of dollars and coins values
money = [10000.0, 5000.0, 1000.0, 500.0, 100.0, 50.0, 20.0, 10.0, 5.0, 1.0, 0.5, 0.25, 0.1, 0.05, 0.01]
count = 0

while(True):
	count += 1
	amount = 0.0
	
	# Recieve the wanted amount of money
	amount = float(r.recvline()[1:])
	print "Wanted amount is " + str(amount)

	# Send the number of dollars and coins for each value
	for m in money:
		print r.recv()
		ans = int(amount/m)
		print "Sending %d" %ans
		r.sendline(str(ans))
		amount = round((amount - (ans*m)), 2)
		print "Left with " + str(amount)
	print "[+] Finished %d" %count
	print r.recvline()