gistfile1.txt

def gen_nonce():
    """Generates a random string of bytes, base64 encoded"""
    length = 64
    string = base64.b64encode(os.urandom(length), altchars=b'-_')
    b64len = 4 * min(length, 3)
    if length % 3 == 1:
        b64len += 2
    elif length % 3 == 2:
        b64len += 3
    return string[0:b64len].decode()