Source : Free On-Line Dictionary of Computing

IPsec
     
         ("{IP} Secure"?) A {protocol}
        that provides {security} for transmission of sensitive
        information over unprotected {networks} such as the
        {Internet}.  IPsec acts at the {network layer}, protecting and
        authenticating {IP} {packets} between participating devices
        ("peers"), such as {Cisco} {routers}.
     
        {IETF IPsec (http://www.ietf.org/ids.by.wg/ipsec.html)}.
     
        (2002-05-06)