encryption of the message into zlib

from codecs import encode
from functools import reduce

print reduce(encode, ('utf8', 'zlib', 'hex'), "this is my message on the postcard")
#output: 789c2bc9c82c5600a2dc4a85dcd4e2e2c4f45485fc3c85928c548582fce292e4c4a21400da1a0c9e

output hex, save to file post.txt

78 9c 2b c9 c8 2c 56 00 a2 dc 4a
85 dc d4 e2 e2 c4 f4 54 85 fc 3c
85 92 8c 54 85 82 fc e2 92 e4 c4
a2 14 00 da 1a 0c 9e

decryption of the message

d = open("post.txt", "r").read().strip()
d = d.replace("\n", " ").split(" ")
d = bytearray([int(x, 16) for x in d])
open("post.bin", "wb").write(d)


open("post.bin", "rb").read().decode("zlib")
# output: 'this is my message on the postcard'