I want to design an application that reads some a folder of text files and shows the user its contents. Three problems arise: I need the folder containing the text files to be encrypted which I don't know how to do, two, I need a way to read the encrypted files without revealing the key in the python code, so I guess C would be the best way to do that even if I don't like that way(any suggestions are welcome,using python if possible), and three, I need a way to add files to the folder and then send the encrypted folder along with the program.
Is there any way to do those things without ever revealing the key or giving the user the possibility to read the folder except using my program?
Thanks in advance for any help!
EDIT: Also, is there a way to use C to encrypt and decrypt files so that I can put the key in the compiled file and distribute that with my program?
I think the best thing to do would be to encrypt the individual text files using GPG, one of the strongest encryption systems available(and for free!) You can get several python libraries to do this, and I recommend python-gnupg. Also, you can probably just reference the file where the key is located and distribute it along with the application? If you want to include a preset key and not have your users be able to see where that key is, you are going to have a very hard time. How about using a key on a server you control that somehow only accepts requests for the key from copies of your application? I don't know how you'd make this secure though through Python.
About adding files to the folder and sending it along with the program, perhaps you aren't thinking of the most optimal solution? There are plenty of python data structures that can be serialized and accomplish most of the things you are talking about in your post.
Related
I have saved the game data to an ini file, how can I protect it from being edited by the user?
Strictly speaking, it's not possible. You can't do anything to a local file that user is unable to undo.
However, you can obfuscate or encrypt (however simply) that file, so that at least a casual person with a Notepad is likely to give up. The simplest thing to do is to save data as a pickle file, so that it's easy to manipulate in Python, but looks baffling to a non-techy user/player.
Make somehow a hash / control sum of your ini-file and store at separate file. It will not prevent the ini-file from modification but you'll be able to know if modification occured and react on such user's behaviour.
I would like to store some information for a game I'm making in python using text files. Some of the information stored shouldn't be changeable for the user. Is there any easy way to make the files unopenable/unreadable for a user, however it would still be saved in the same directory. (Preferably without the use of external libraries, however if that is the easiest or only way then that's fine)
This might help:
You'd need to make the files not readable for users other than you, so the mode should probably be 0o700.
import os
os.chmod(path, 0o700)
Alternatively, you can also use chmod with a terminal: chmod 700 path/to/your/file.
You can't make the file unopenable or unreadable its the users computer so they can do whatever they want.
however, I have an Idea, but it won't stop a smart one
use
Ceaser Cipher also called Shift cipher
This vid Will How to Use the Caesar (Shift) Cipher
simply it is swapping letter with another, like
if your file is like
{
"name","Joe"
}
apply a ceaser cipher with key = 6,you will get
{
"tgsk","Puk"
}
however if he is smart, its likely he is gonna be able to decrypt it easily and know the key
at the end its their computer they can do whatever they like with you file
I am currently working on a script that automatically syncs files from the Documents and Picture directory with an USB stick that I use as sort of an "essentials backup". In practice, this should identify filenames and some information about them (like last time edited etc.) in the directories that I choose to sync.
If a file exists in one directory, but not in the other (i.e. it's on my computer but not on my USB drive), it should automatically copy that file to the USB as well. Likewise, if a file exists in both directories, but has different mod-times, it should replace the older with the newer one.
However, I have some issues with storing that information for the purpose of comparing those files. I initially thought about a file class, that stores all that information and through which I can compare objects with the same name.
Problem 1 with that approach is, that if I create an object, how do I name it? Do I name it like the file? I then would have to remove the file-extension like .txt or .py, because I'd run into trouble with my code. but I might have a notes.odt and a notes.jpg, which would be problem 2.
I am pretty new to Python, so my imagination is probably limited by my lack of knowledge. Any pointers on how I could make that work?
So I made a python phonebook program which allows the user to add contacts, change contact info, delete contacts, etc. and write this data to a text file which I can read from every time the program is opened again and get existing contact data. However, in my program, I write to the text file in a very specific manner so I know what the format is and I can set it up to be read very easily. Since it is all formatted in a very specific manner, I want to prevent the user from opening the file and accidentally messing the data up with even just a simple space. How can I do this?
I want to prevent the user from opening the file and accidentally messing the data up...
I will advise you not to prevent users from accessing their own files. Messing with file permissions might result in some rogue files that the user won't be able to get rid of. Trust your user. If they delete or edit a sensitive file, it is their fault. Think of it this way - you have plenty of software installed on your own computer, but how often do you open them in an editor and make some damaging changes? Even if you do edit these files, does the application developer prevent you from doing so?
If you do intent to allow users to change/modify that file give them a good documentation on how to do it. This is the most apt thing to do. Also, make a backup file during run-time (see tempfile below) as an added layer of safety. Backups are almost always a good idea.
However, you can take some precautions to hide that data, so that users can't accidentally open them in an editor by double-clicking on it. There are plenty of options to do this including
Creating a binary file in a custom format
Zipping the text file using zipfile module.
Using tempfile module to create a temporary file, and zipping it using the previous option. (easy to discard if no changes needs to be saved)
Encryption
Everything from here on is not about preventing access, but about hiding the contents of your file
Note that all the above options doesn't have to be mutually exclusive. The advantages of using a zip file is that it will save some space, and it is not easy to read and edit in a text editor (binary data). It can be easily manipulated in your Python Script:
with ZipFile('spam.zip') as myzip:
with myzip.open('eggs.txt') as myfile:
print(myfile.read())
It is as simple as that! A temp file on the other hand, is a volatile (delete=True/False) file and can be discarded once you are done with it. You can easily copy its contents to another file or zip it before you close it as mentioned above.
with open tempfile.NamedTemporaryFile() as temp:
temp.write(b"Binary Data")
Again, another easy process. However, you must zip or encrypt it to achieve the final result. Now, moving on to encryption. The easiest way is an XOR cipher. Since we are simply trying to prevent 'readability' and not concerned about security, you can do the following:
recommended solution (XOR cipher):
from itertools import cycle
def xorcize(data, key):
"""Return a string of xor mutated data."""
return "".join(chr(ord(a)^ord(b)) for a, b in zip(data, cycle(key)))
data = "Something came in the mail today"
key = "Deez Nuts"
encdata = xorcize(data, key)
decdata = xorcize(encdata, key)
print(data, encdata, decdata, sep="\n")
Notice how small that function is? It is quite convenient to include it in any of your scripts. All your data can be encrypted before writing them to a file, and save it using a file extension such as ".dat" or ".contacts" or any custom name you choose. Make sure it is not opened in an editor by default (such as ".txt", ".nfo").
It is difficult to prevent user access to your data storage completely. However, you can either make it more difficult for the user to access your data or actually make it easier not to break it. In the second case, your intention would be to make it clear to the user what the rules are hope that not destroying the data is in the user's own best interest. Some examples:
Using a well established, human-readable serialization format, e.g. JSON. This is often the best solution as it actually allows an experienced user to easily inspect the data, or even modify it. Inexperienced users are unlikely to mess with the data anyways, and an experienced user knowing the format will follow the rules. At the same time, your parser will detect inconsistencies in the file structure.
Using a non-human readable, binary format, such as Pickle. Those files are likely to be left alone by the user as it is pretty clear that they are not meant to be modified outside the program.
Using a database, such as MySQL. Databases provide special protocols for data access which can be used to ensure data consistency and also make it easier to prevent unwanted access.
Assuming that you file format has a comment character, or can be modified to have one, add these lines to the top of your text file:
# Do not edit this file. This file was automatically generated.
# Any change, no matter how slight, may corrupt this file beyond repair.
The contact file belongs to your user, not to you. The best you can do is to inform the user. The best you can hope for is that the user will make intelligent use of your product.
I think the best thing to do in your case is just to choose a new file extension for your format.
It obviously doesn't prevent editing, but it clearly states for user that it has some specific format and probably shouldn't be edited manually. And GUI won't open it by default probably (it will ask what to edit it with).
And that would be enough for any case I can imagine if what you're worrying about is user messing up their own data. I don't think you can win with user who actively tries to mess up their data. Also I doubt any program does anything more. The usual "contract" is that user's data is, well, user's so it can be destroyed by the user.
If you actually won't to prevent editing you could change permissions to forbid editing with os.chmod for example. User would still be able to lift them manually and there will be some time window when you are actually writing, so it will be neither clean nor significantly more effective. And I would expect more trouble than benefit from such a solution.
If you want to actually make it impossible for a user to read/edit a file you can run your process from a different user (or use some heavier like SELinux or other MAC mechanism) and so you could make it really impossible to damage the data (with user's permissions). But it is not worth the effort if it is only about protecting the user from the not-so-catastophic effects of being careless.
I'm looking to store some individual settings to each user's computer. Things like preferences and a license key. From what I know, saving to the registry could be one possibility. However, that won't work on Mac.
One of the easy but not so proper techniques are just saving it to a settings.txt file and reading that on load.
Is there a proper way to save this kind of data? I'm hoping to use my wx app on Windows and Mac.
There is no proper way. Use whatever works best for your particular scenario. Some common ways for storing user data include:
Text files (e.g. Windows INI, cfg files)
binary files (sometimes compressed)
Windows registry
system environment variables
online profiles
There's nothing wrong with using text files. A lot of proper applications uses them exactly for the reason that they are easy to implement, and additionally human readable. The only thing you need to worry about is to make sure you have some form of error handling in place, in case the user decides to replace you config file content with some rubbish.
Take a look at Data Persistence on python docs. One option a you said could be persist them to a simple text file. Or you can save your data using some serialization format as pickle (see previous link) or json but it will be pretty ineficient if you have several keys and values or it will be too complex.
Also, you could save user preferences in an .ini file using python's ConfigParser module as show in this SO answer.
Finally, you can use a database like sqlite3 which is simpler to handle from your code in order to save and retrieve preferences.