Last year sometime I had written a simple text encryption program for windows using C#. It has a box to type in a message, another box to type in a key, and an output box that combines the two using essentially a viginere table. The neat thing is that if one uses a one-time pad as a key, in other words, the key is illogical and never repeating or reused, the code is 100% unbreakable. For the less "security minded", I did add a checkbox that allows the use of a passphrase which will internally repeat as necessary, although that would make for a weak encryption and its use is not recommended for any serious messages. Also build in is the ability to salt the key with a password (in the event your one-time codebook was compromised) ~ call it an added bit of security. With that function is a checkbox that will hide the salted key from the key window so onlookers will not see the true key. There is a help button detailing the use of each function which essentially calls open the help.txt file in the unzipped folder ~ deleting this file will make the help button not work. There is an option to import and export text files into the windows for those confident (and crazy) enough to keep keys stored on their computer, but I wouldn't recommend that unless the PC never sees internet.
I had originally thought I had lost the program, but luckily found the final stable version of the exe sitting in my google drive account. I no longer have the code used to make it, but a free program called JustDecompile is able to let someone see the code it runs on. I originally wanted to edit it because my ham callsign is in the main window of the program, but I decided it wasn't worth removing and, IMO, supports the fact there is nothing shady about the program (for those not interested in using a decompiler to look into it for themselves). I will try to attach it here, not sure if that will work. Any questions about it, id be happy to answer. Heres a screenshot. Some day soon I will be rebuilding this and adding a com port option for sending the output box to a USB to UART serial converter and interface that with my radio, just need to find the time.
I had originally thought I had lost the program, but luckily found the final stable version of the exe sitting in my google drive account. I no longer have the code used to make it, but a free program called JustDecompile is able to let someone see the code it runs on. I originally wanted to edit it because my ham callsign is in the main window of the program, but I decided it wasn't worth removing and, IMO, supports the fact there is nothing shady about the program (for those not interested in using a decompiler to look into it for themselves). I will try to attach it here, not sure if that will work. Any questions about it, id be happy to answer. Heres a screenshot. Some day soon I will be rebuilding this and adding a com port option for sending the output box to a USB to UART serial converter and interface that with my radio, just need to find the time.

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