A858 AMA Decoder

#!/usr/bin/env python

import sys

with open("key") as f:
        key_lines = f.readlines()

msg = sys.argv[1]

outchars = ""
for i in range(len(msg) / 4):
        x = int(msg[i*4:i*4+2], 16)
        y = int(msg[i*4+2:i*4+4], 16)
        line = key_lines[y]
        outchars += "%c" % line[x]

i = 0
while i < len(outchars):
        if outchars[i] == '1':
                num = outchars[i:i+3]
                i += 3
        else:
                num = outchars[i:i+2]
                i += 2
        sys.stdout.write("%c" % int(num))

print