This time, however, I decided to expand on its methods and basically make an all-in-one stop for encryption / decryption.
So its something I wanted to make for my own use and figured I might as well share it with you guys. 🙂
Beware though: recursion can be dangerous if used without knowledge. You could end up encrypting your entire system. Also this script will automatically delete the old files after encryption / decryption.
Download link is at the bottom of the post!
Script Requirements
I won’t go into any details regarding the code since I’ve already made a blog post and video going into detail for this exact code.
Anyway, you will need to install pyAesCrypt. This is easiest using pip:
We’re off to part five of our little Python control server.
I had been postponing this, but its time we implement multiple clients!
I knew we had to do this right and that it would most likely bloat the scripts as well, so it would also require breaking it down into specific modules.
So yeah, that’s what we’re doing, lets get into it!
But before that, let me give you guys some context into the code…
Modular Programming
Many times when working on a project, as it begins to expand and get into a few hundred lines of code we need to start breaking it up into modules.
For our project, so far, it seems most of the functionality is divided between server configuration and data encryption.
I figure, just for the sake of development and teaching proper methods to keep working in a program without feeling like its a labyrinth, we’ll go ahead and separate our code into a few modules.
In this part we’ll be implementing file transfer and encryption.
I use these programs on my own system and you absolutely have to be able to download and upload files in order to get anything done.
Now some of you might remember in part three I mentioned that our encrypted channel wasn’t stable enough to handle several megabytes of data without any mishaps.
Because of that, I had to implement file encryption and decryption in the client as well, since we’re already working with pyAesCrypt anyway.
This allows us to, at the very least, encrypt files locally before sending them over a standard tcp tunnel – or keep them encrypted on the system.
Like much of the functionality we’re going through here, these functions could be copied and used in other code without much hassle.
[ Part 1 – Part 2 – Part 3 – Part 4 – Part 5 – Part 6 – Part 7 – Part 8 ]
What’s going on guys?
Welcome to part three of the Python control server series.
In part one we created our simple server and client with about 20 lines of code each (Python 3). Then in part two, we’ve added basic AES encryption to our traffic using pyAesCrypt.
Given the nature of encryption using pyAesCrypt, we we’re unable to receive any data on the server over 1024 bytes with encryption. The main reason for this is that length needs to be passed for the decryption method.
In this part we will be fixing this issue, so let’s get with it.
Traffic Encryption
What exactly is the issue we have here? Why is less than 1024 bytes ok?
Both in our server and client we are sending 1024 bytes at a time. This means that whenever we send a message containing less than 1024 bytes, we won’t run into any issues.
Now considering we have to pass a length argument for decryption, if we send a message that is 1500 bytes, the server will receive the first 1024 bytes and attempt to decrypt it – resulting in an error.
This is where we have a few different options: receive all the encrypted data and then decrypt it all at once; or, receive smaller chunks of data and decrypt on-demand. Both options have their merits, I decided this latter one would be easier to program for a encryption noob like me. 🙂
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