So, what my program does can be deduced from the images above. The third reason was to better understand all the operations on bits, bytes etc.I thought about encrypting with bigger keys (because currently the safe RSA key is considered to be 2048 bits), and to encrypt the file on multi-core machines. It was then that I thought to create an RSA example, more close to that what is used in practice, and to provide it for all that want to understand how it works. The harder part was that we were supposed to calculate the approximate time of encryption and the decryption at runtime, like in the case when Windows explorer calculates how many minutes you have to wait until all the files are copied. In 2010, when I was doing my master degree at another university, there were some requests from my fellow students at the original University to provide them my RSA project as an example, so for them to be easier to understand how to implement it.Anyway, I didn't do anything in this direction al all. This was enough for the practice lessons, the single problem was that the key was very small, and I wanted to know how to encrypt with bigger keys. The enc/dec key had several bits, no more. So I implemented this algorithm, and encrypted every byte using it. This was not so hard, but a little challenging for the one that never did any kind of encryption. At university, in 2009, I had the task to implement the RSA algorithm.There were many reasons why I wanted to do this:

At the end of december 2010 I started to do some research on the RSA implementation with big encryption/decryption keys.

C# rsa example