Security infrastructure for modern information and message exchange systems, networks and applications

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The program addresses problems with communications security infrastructure used for virtually all web communications and secure email systems. Issues addressed involve certificate-based public key infrastructure (PKI), trust management, systems security, and supporting authentication and identity management mechanisms. The model underlying essentially all secure communications today involves a Certification Authority (CA) binding a public key to an entity identifier, creating a public key certificate. Problems without satisfactory solutions include mechanisms: to reliably verify the legitimacy of bindings asserted in certificates, and their ongoing validity (revocation status); to configure software to “trust” an appropriate set of CAs, in order to automate certificate verification; to limit the ability of CAs to create certificates for arbitrary web sites and email users; to increase visibility when CAs delegate trust to subordinate authorities; to distinguish rogue certificates from those legitimately issued; to prevent downgrading secure HTTPS web sessions to unsecured HTTP; to eliminate current fragility whereby compromise of a single CA can undermine trust in the entire infrastructure. Problems are considered in two primary PKI use cases. The web communications focus is on the TLS protocol (including as used by HTTPS), the backbone of Internet security for site authentication, encryption, and integrity of browser-server data and downloaded software. The email focus spans end-to-end secure email and link-based secure email via TLS. The program seeks to improve or replace exploitable security mechanisms. The recent surge of research on such systems stems from essentially all of society's critical infrastructures -- power, transportation, finance, communications -- depending on the Internet, despite most of the thousands of CAs browsers and email software “trust” to issue certificates being unrecognizable to end-users. This infrastructure is widely recognized as vulnerable to cyber-attack in this post-Snowden era of increased awareness about how easily systems are compromised, and of the elevated consequences due to physical society's reliance on our digital infrastructure. HTTPS is acknowledged by experts to be a critical but fundamentally flawed infrastructure, while email is a foundation for business communications but remains almost entirely unsecured. The program results will improve fundamental understanding of how to build and maintain robust, secure information exchange systems, address root causes of security infrastructure flaws, and provide new approaches to address current limitations. Results are expected to find their way into widely deployed software systems used for government, enterprise and private communications.