Their storage backend implementation is open source.
All the pieces required to deploy and operate your own Manta are open source
Triton Object storage touts itself as
Proven at production scale, Triton Object Storage delivers replication, clustering, failover, and backup and recovery capabilites. Robust security is built in, including object level security and access, deep role based access control, and client SSH and data encryption.
Update: Read more about the Triton Object Storage and Cyberduck on the Joyent Blog.