The US Federal PKI is designed around the Federal Bridge Certification Authority. This innovative approach allows US federal agencies to operate their own public key infrastructures and interoperate with the public key infrastructures of other agencies in a highly simplified architecture that minimizes cross-certification management and enhances technical interoperability. The Federal Bridge implicitly establishes standards of assurance for its participating members and enhances interoperability standards among PKI product and service vendors. The US higher education and health care communities are building similar bridges and they plan to interoperate with the Federal Bridge, thereby creating a new PKI support infrastructure.