SU-CTF Crypto200 one Line encoder

oneline_encoder.py

suctf_enc = lambda text, key: reduce(lambda x, y: (x[0] + str(int(y) ^ int(x[1][0])), x[1][1:] + str(int(x[1][4]) ^ int(x[1][0]))), ''.join(map(lambda x: bin(ord(x))[2:].rjust(8, '0'), text)), ('', key))[0]

def split_n(s, n):
    return [s[i:i+n] for i in range(0, len(s), n)]

def enc(text, key):
    r = ''
    text = ''.join(map(lambda x: bin(ord(x))[2:].rjust(8, '0'), text))
    for (t,s) in zip(text, gen_key(key,len(text))):
        r += str(int(t) ^ int(s))
    return r

def dec(text, key):
    r = ''
    for (t,s) in zip(text, gen_key(key,len(text))):
        r += str(int(t) ^ int(s))
    rr = ''
    for c in split_n(r, 8):
        rr += chr(int(c,2))
    return rr

def gen_key(s, n):
    r = []
    for i in range(n):
        r.append(s[0])
        s = s[1:] + str(int(s[0]) ^ int(s[4]))
    return r

print enc('hoge', '101010101')
print dec('11000010111011100010110110010111', '101010101')

encrypted = '11010001011100101100100101011110000110100111111101101001101101111000001010100100011000001001011111011111101000111011111000110111010111100110000000100000101101001000011010111111101010101111011110100011101100001010000010100110001000010100001001110011011011100010011011101110100111011011101011111110001101011101010110001001111101011011011011100000001001110101010101101010111010100001010011010011110001001011010000101011010001111010111111010011011111100100110110111001000011010000111000111100011000110011000111100011010100000100101110110111000111011000001101010111010001111110000010011111101110100110101010001001100100000111010011011011000011100000110101111100111011011101011010111011101110110111011101001010111110011000101111100000111110111010000000100011000100001111000011000010011000111000110011011000011001100000101100101001101011000100101111011100010100101100111100001111010111111011010000000110000110010110010111100111110001101011110000111111000001000110100010111110110001100011001110010101110111010110011110001111010111011001010000010010110100001001000011110100'

for key in range(2**9):
    key = bin(key)[2:].rjust(8, '0')
    decrypted = dec(encrypted, key)
    if 'is' in decrypted:
        print decrypted
        print 'key:', key