base64 is installed on my freshly installed Fedora 19 where I only installed the dependencies for tincd.

The current directory when the exploit lands is / and is only writable when the deamon runs as root. When the deamon runs as root the current directory is the better choice, as an unprivileged user /tmp is the better choice. I thought it's probably best if it's customizable, see commit e5a237a98b9998aa58bbb63b90c7178e63fc88bb