The Secret Internet Protocol Router Network (SIPRNet) is the Department of Defense network for the exchange of classified information and messages at the SECRET level. It supports the Global Command and Control System, the Defense Message System, and numerous other classified warfighting and planning applications. Although the SIPRNet uses the same communications procedures as the Internet, it has dedicated and encrypted lines that are separate from all other communications systems. It is the classified counterpart of the Unclassified but Sensitive Internet Protocol Router Network (NIPRNET), which provides seamless interoperability for unclassified combat support applications and controlled access to the Internet.
Access to the SIPRNet requires a SECRET level clearance or higher and a need to have information that is available only on the SIPRNet. Because the SIPRNet is an obvious target for hostile penetration, a number of strict security procedures are applied. Appropriate credentials and two-factor authentication are required. When using the SIPRNet, you must not leave the workstation unattended.
A computer with a non-removable hard drive used to access the SIPRNet must be located in an area approved for open storage of SECRET information. A computer with a removable hard drive does not have to be in an open storage location, but the hard drive must be appropriately marked with the classification of the material it contains and, when not in use, must be removed and stored in a container approved for the storage of SECRET information. If physical keys are used, they will be numbered and stored in a container approved for the storage of SECRET material.
Linking a computer with access to the SIPRNet to the Internet or to any other computer or media storage device that has not been approved for use with SECRET information is a serious security violation. Once any media storage device such as a CD or thumb drive has been connected to a computer with access to the SIPRNet, it becomes classified at the SECRET level. It must be protected accordingly and shall not be used on any unclassified computer.
Technological advances in storage devices are making it easier for classified information to be removed from secure areas. Data-storage devices such as Personal Digital Assistants (PDA), Key-chain drives, Memory watches etc, should not be allowed in an environment where classified information is processed because of their infrared and similar recording capabilities. For computers used to process classified information, it is recommended that infrared (IR) port beaming capability be disabled. If the IR port is unable to be disabled, cover the IR port with metallic tape.
The SIPRNet system maintains
an audit trail of all users. This includes the identity of all persons
accessing or attempting to access the SIPRNet, date and time of
logon/logoff, and any noteworthy activities that might indicate an attempt
to modify, bypass, or negate security safeguards.