The Joint Worldwide Intelligence Communications System (JWICS pronounced JAYwicks), is a system of interconnected computer networks used by the United States Department of Defense and the United States Department of State to transmit classified information by packet switching over TCP/IP in a secure environment.
It is cleared up to Top Secret and SCI. It also provides services such as hypertext documents and electronic mail. In other words, the JWICS is the DoD’s Top Secret version of the Internet together with its Secret counterpart, SIPRNet. JWICS superseded the earlier DSNET2 and DSNET3, the Top Secret and SCI levels of the Defense Data Network based on ARPANET technology.[1][2]
In day-to-day usage, the JWICS is used primarily within the intelligence community, with SIPRNet and NIPRNet comprising the overwhelming bulk of usage within US DoD.
JWICS was allegedly one of the networks accessed by Bradley Manning, who is accused of leaking massive amounts of material, including the video used in Wikileaks' Collateral murder and US diplomatic cables. [3]