def has_repeated_cipertext(hex_string: str, key_bytes: int = 16) -> bool:
    """Identify if there is repeated ciphertext in a hex string."""
    key_size = key_bytes * 2
    hex_length = len(hex_string)

    blocks = set(hex_string[b : b + key_size] for b in range(0, hex_length, key_size))

    return len(blocks) < hex_length / key_size