import struct

def lcg(m, a, c, x):
    return (a*x + c) % m

m = pow(2, 32)
MAXL=15000
list_x=[];
def encrypt():

    with open('lcg') as f:


        a = int(f.readline())
        c = int(f.readline())
        x = int(f.readline())

    d = open('nghia.txt').read()

    e = ''
    d += '\x00' * (-len(d) % 4)
    d = [d[i:i+4] for i in range(0, len(d), 4)]

    e = ''
    for i in range(len(d)):
        e += struct.pack('>I', x ^ struct.unpack('>I', d[i])[0])

        print struct.pack('>I', x ^ struct.unpack('>I', d[i])[0])
        x = lcg(m, a, c, x)


    with open('nghia.enc.txt', 'w') as f:
        f.write(e)
        f.close()