Zix Corporation announced Friday that it was granted a U.S. patent for a secure transmission system used in its email encryption services.

The newly patented system has features that are designed to simplify the process of sending and receiving encrypted email, the company said.

The features include real-time public key retrieval, "transaction certificates," and sending encrypted messages using a non-SMTP protocol through a forwarding server.

The patent is the third awarded to Zix this year. Previously, the Dallas-based company received patents for a secure message forwarding system and transaction authorization system.