The called "Key Manager", now has the random function, so that you can now have the letters randomly chosen.
(It can sometimes happen that the boxes are all empty. This is because the program would be in a weird endless loop. If this happens just press it again).
As well as that you can assign the letters duplicate. Which of course makes the decryption impossible!
There are 2 versions available:
"Standalone" is optimal if there is NO .NET 6 on this machine. (is bigger)
"Not Standalone" is good if there is .NET 6 on this machine. (is smaller)