Private key accepted.

You are so close to finishing the challenge...
The 4th secret piece is: fingerprint

You fire up SSHarp with your newly generated private keys, and wait for the communication. After some days Anderson finishes the analyzing of the good code, digitally signs it, and sends the files to VSA. They open a new ssh/scp flow, but don't accept your private key. You are waiting, and waiting, when you hear a police sirene near to you. You almost destroy your computer when finally Anderson accepts your key file. They just needed some time to verify the digits by phone...
After changing the good program to the evil one, you imagine what your virus will do at VSA. Your boss will be very proud of you... You have only one thing left to do: Cover your tracks at the router configuration.