Fun crypto problem: Exploiting a vulnerable encryption scheme with Python
The conversions to bit-strings, then ints and back to strings are unnecessary.  m and k are bytes, so the elements (e.g., m[0] or k[i]) are already integers in the range 0-255;  bitwise operators can be applied to the elements directly.

I think routines in the Crypto library return strings, so the encrypt() return value might need to be encoded before using it.

from Crypto.Cipher import DES

m = b'secret!!'
k = b'qwerty!!'
E = DES.new(k, DES.MODE_ECB)
C = E.encrypt(m)

C = C.encode()  # &lt;- needed if encrypt() returns a string (i.e., not bytes)

C_alpha = bytes(x^y for x,y in zip(C, m))

C_beta  = bytes(x^0xff for x in C)

C_omega = C_alpha + C_beta