encrypted text editor

spent about an hour writing the process of setting up plaintext for AES, but then as i tested it, i realized i hadn’t accounted for all edge cases and hadn’t written very efficient or elegant code so I decided to take a step back, write out the process on paper, and then rewrite the methods. Here’s that:

plaintext (string) -> binary equivalent with space between each byte (string) -> add trailing zeros to binary string to make the number of bits divisible by 128 to make full blocks without errors -> create an array of each byte in the binary equivalent string (string[]) -> create an array of 128 bit (4x4 byte) blocks, organizing the bytes from the previous string[] in column-major order into each block (string[][][])

having it clearly written out and having already experimented with it, i was able to write cleaner code by writing a method for each step of this process, each taking the lasts output as input, and then writing a final method which executes each of these methods in the correct order, turning plain text into the necessary blocks of binary data. I have attached this method below as I figure the rest of the code is too long to show and this project doesn’t really have any cool graphics to showcase yet.

next, i have to figure out how to generate salts and write a key generation function. alternatively, i could also take a break from the encryption/decryption aspect of this project and figure out the file management system, since i’ve never worked with that before, or i could also get started on the ui.

after reading up a little more on AES and still not fully understanding all of the processes I’ll need to implement, I figured I should just start writing the parts I do know I’ll need.
I wrote a method that converts a string of plain text to a string of it’s binary equivalent, then another that splits that string of binary into bytes (every 3 digits) and adds each one to an array, and another that prints it in a readable manner for testing purposes.
I’m still not done implementing the binary string to byte[] function as I just realized that the reason the byte variable type has 3 digits and not 4 is because it is not encoded in binary and I did not account for that in my code. I have a feeling I might find more systemic errors and/or redundancies in my code tomorrow as I’ve barely touched java (or coding for that matter) for 2 years, but I’ll work through them tomorrow and then move on the next step, which I believe is turning that 1D byte array into a 2D 4x4 column-major byte array for each 128 bits of text being encrypted.

Today I set up a brand new Github account, made a repository for this project, and connected it with VScode. I settled on using Java over Python, since I figured I needed a refresher after taking AP CSA 2 years ago. Then I spent about an hour researching encryption algorithms. Attached is my best understanding of how the encryption should be implemented/will work.