sbd is a Netcat-clone, designed to be portable and offer strong
encryption. It runs on Unix-like operating systems and on Microsoft
Win32. sbd features AES-CBC-128 + HMAC-SHA1 encryption (by Christophe
Devine), program execution (-e option), choosing source port, continuous
reconnection with delay, and some other nice features. Only TCP/IP
communication is supported. Source code and binaries are distributed
under the GNU General Public License.

sbd can be used for any number of network-related things, e.g.:

    * Secure file transfer
    * Remote administration
    * Simple (but secure) peer-to-peer chat
    * Pen-test tool (crypto avoids NIDS detection and telnet-style 
      traffic recording) 

WWW: http://tigerteam.se/dl/sbd/