The person you send an encrypted file to will also need to have this installed. They offer a free version that only allows one contact, unlimited files. So if all your recipients only need to get files from you, they install the free version and all should work well. AND, since they’re giving us the Plus version, we are limited to 10 contacts.
I think it’s still easier all around to encrypt a file using 7-Zip or similar and send as self-extracting exe that will ask recipient for password. But if you frequently need to transfer files with a limited number of people who don’t mind installing extra software, this looks like a good program. Has anyone used it yet?