This custom activity does not exist in UiPath Studio officially, and it's a common topic in idea contest as well.
What it does
This activity can be used to zip a folder with password and unzipping a file by giving same password. And It can be mainly used to send email attachment in a secure way (By giving password option).
How I built it
The project was built using the following technologies. Visual Studio with .NET Framework 4.5.2 ( Code Activity)
Accomplishments that I'm proud of
User can be use this activity to send secure mail attachments .
What I learned
I learned a lot about how and when need to develop custom activities for achieve robotic process automation using .NET
What's next for Zip /Unzip Activity -UiPath custom activity
Take this simple activity as initial step and make more complex solutions in future.