Less is more: cipher-suite negotiation for DNSSEC

Abstract

We propose a transport layer cipher-suite negotiation mechanism for DNSSEC standard, allowing name-servers to send responses containing only the keys and signatures that correspond to the cipher-suite option negotiated with the resolver, rather than sending all the signatures and keys (as is done currently). As we show, a lack of cipher-suite negotiation, is one of the factors impeding deployment of DNSSEC, and also results in adoption of weak ciphers. Indeed, the vast majority of domains rely on RSA 1024-bit cryptography, which is already considered insecure. Furthermore, domains, that want better security, have to support a number of cryptographic ciphers. As a result, the DNSSEC responses are large and often fragmented, harming the DNS functionality, and causing inefficiency and vulnerabilities. A cipher-suite negotiation mechanism reduces responses' sizes, and hence solves the interoperability problems with DNSSEC-signed responses, and prevents reflection and cache poisoning attacks.