iodine lets you tunnel IPv4 data through a DNS server. This can be useful in situations where Internet access is firewalled, but DNS queries are allowed. It needs a TUN/TAP device to operate. The bandwidth is asymmetrical with limited upstream and up to 1 Mbit/s downstream.
Cyphertite is a tar-like secure remote archiver. It deduplicates, compresses, and encrypts data prior to transmission, providing total privacy while reducing unnecessary wire traffic. It seamlessly supports IPv6 and IPv4 on a variety of platforms.