Try using send.firefox.com. From their informaion: "Send lets you upload and encrypt large files (up to 1GB) to share online. When you upload a file, Send creates a link to pass along to whoever you want. Each link created by Send will expire after 1 download or 24 hours, and all sent files will be automatically deleted from the Send server."
I use this and it works well. You just drag and drop you file into Send and it provides you the link. All your precipitant needs to do is click on the link to download your file.