I was wondering, is it possible to trace a packet that you send out of your own computer? The idea here would be to build something to protect your data. The packet sent out containing your password and other vital information is open to rerouting by a hacker. I want to know if it is possible (and if so, how I might go about approaching this) to trace the intermediate and/or final destinations of a certain packet, and then have them sent back to my computer for verification.
I would appreciate any help you guys could give on this matter.
There is no mechanism to do what you want. The packet itself might reach its "destination" just fine, only to be further re-directed elsewhere. Consider it like mailing an envelope -- whoever receives it is free to photocopy the contents a thousand times and send the copies to newspapers, tabloids, and telephone poles all over the world.
Same story with data -- once it leaves your computer, you have to trust the remote endpoint to not do anything harmful with it.
TLS and openPGP can go a long way to preventing third-parties from reading or modifying your data while it is in transit, but they cannot make sure the remote peer only handles your data with care.