The Secret Internet Protocol (IP) Router Network, widely known as SIPRNet, is the U.S. Department of Defense's (DoD) private and secure version of the public internet.
It is a system of interconnected computer networks used to transmit classified information up to the SECRET level.
History and background
SIPRNet was established in 1991 to replace the former Defense Secure Network 1 (DSNET1). It is the "SECRET" component of the Defense Information Systems Network (DISN), which provides information technology and communications services to various U.S. government entities.
Purpose and usage
The network provides a range of services similar to the public internet, including email and access to hypertext documents, but within a highly controlled and encrypted environment. Its primary purpose is to allow for the secure exchange of military operations data and classified communications.
Key distinctions from the public internet
- Access control: Unlike the public internet, SIPRNet is not open to the public. Access is limited to authorized personnel with the required security clearances and a "need-to-know".
- Physical security: Any computer connecting to SIPRNet, such as at a command post, must be located in an area approved for handling classified information. Devices used to store or transfer data from the network are automatically classified at the SECRET level.
- Encryption and protocols: SIPRNet uses its own secure, encrypted protocols for communication to ensure sensitive information is not exposed to unauthorized parties.
The wider ecosystem of secret networks
SIPRNet is just one part of a broader network infrastructure for military and intelligence communications. The U.S. government maintains several distinct, air-gapped networks to handle information of varying sensitivity:
- NIPRNet (Non-classified Internet Protocol Router Network): The network for routine, unclassified, but sometimes sensitive information. It is functionally the military's equivalent of the regular internet.
- JWICS (Joint Worldwide Intelligence Communications System): An intranet system used for transmitting information classified at the TOP SECRET and Sensitive Compartmented Information (SCI) levels.
Technical structure
SIPRNet relies on the Defense Information Systems Network (DISN) and is managed by multiple agencies, including the Defense Information Systems Agency (DISA) and the National Security Agency (NSA). To connect to SIPRNet, a user's computer uses a secure line to connect to a SIPRNet server, which then establishes an encrypted connection that meets strict, pre-designated standards.
Impact and implications
The existence of segregated, classified networks like SIPRNet is critical for national security, enabling secure communication and information sharing for military and diplomatic operations. It highlights the layered nature of the digital world, where the civilian "internet" is only one part of a more complex landscape that includes private, encrypted, and highly restricted communication networks.