PeaZip is nothing more than a front-end (GUI) for 7-zip...it also adds more features to 7-zip.
So if you're using PeaZip, then all the archiving and encryption is performed by 7-zip.
If you are inclined, PeaZip also offers a command line console.
I use PeaZip as it is fully featured and for whatever reason(s), 7-zip just plain gave me a hard time on my system. Couldn't figure that one out...but what the heck...PeaZip works rather well!
Finally, if you install PeaZip after installing certain supported AV, then you can scan within the archive before extracting it using the PeaZip archive browser. Can be quite a handy little feature.
For a list of supported AV you have to go to the PeaZip Source Forge page and select "Security." FYI, there is a bug and I've reported it to the developer...currently, PeaZip is only detecting Windows Defender on my W8.1 system, but it may be completely different on another system. So, in other words, you have to try it.
IMPORTANT!: Again, PeaZip has to be installed after the supported AV.