Deploying Cryptography in Internet-Scale Systems: A Case Study on DNSSEC

The DNS Security Extensions (DNSSEC) are among the first attempts to deploy cryptographic protections in an Internet-scale operational system. DNSSEC applies well-established public key cryptography to ensure data integrity and origin authenticity in the DNS system. While the cryptographic design of DNSSEC is sound and seemingly simple, its development has taken the IETF over a decade and several protocol revisions, and even today its deployment is still in the early stage of rolling out. In this paper, we provide the first systematic examination of the design, deployment, and operational challenges encountered by DNSSEC over the years. Our study reveals a fundamental gap between cryptographic designs and operational Internet systems. To be deployed in the global Internet, a cryptographic protocol must possess several critical properties including scalability, flexibility, incremental deployability, and ability to function in face of imperfect operations. We believe that the insights gained from this study can offer valuable inputs to future cryptographic designs for other Internet-scale systems.