2 steps text encrypting with USB key - C#

It is a 128-bit encryption program that is encrypted by two keys, the second key is stored in external memory such as USB, and the first key is encrypted inside the program. The first key is needed to open the text you were encrypting, but the first key is encrypted with the second key, so to open the first key, we need the second key, which is inside the USB flash drive.

After connecting USB to the computer, the program automatically reads the key and can open the encrypted text! USB is needed for both encrypting and decrypting.