secret_message.py

from random import Random

def generate_bytes_for_seed(seed: int, message: str) -> bytearray:
    data = Random(seed)
    garbage = Random(34988394)

    data.seed(seed)
    result = bytearray()
    i = 0
    while i < len(message):
        c = message[i]
        if data.randrange(2):
            result.append(data.randrange(256) ^ ord(c))
            i += 1
        else:
            result.append(garbage.randrange(256))
    return result

seed = 69420
message = 'Your secret message!'
print(f"""import random
random.seed({seed})
print(''.join(chr(random.randrange(256) ^ c)
    for c in bytes.fromhex({repr(generate_bytes_for_seed(seed, message).hex().upper())})
    if random.randrange(2)))
""")

Really cool ! Good job

Isn't the line 7 redundant as the seed was already set in the line 4?

@Ernest1338 You are right ! That seed definition in line 7 is redundant