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Is the web ready for OSCP must-staple?

Taejoong Chung, Jay Lok, Balakrishnan Chandrasekaran, David Choffnes, Dave Levin, Bruce M. Maggs, Alan Mislove, John Rula, Nick Sullivan, Christo Wilson
Proceedings of the Internet Measurement Conference 2018, pp. 105-118. 2018.
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TLS, the de facto standard protocol for securing communications over the Internet, relies on a hierarchy of certificates that bind names to public keys. Naturally, ensuring that the communicating parties are using only valid certificates is a necessary first step in order to benefit from the security of TLS. To this end, most certificates and clients support OCSP, a protocol for querying a certificate's revocation status and confirming that it is still valid. Unfortunately, however, OCSP has been criticized for its slow performance, unreliability, soft-failures, and privacy issues. To address these issues, the OCSP Must-Staple certificate extension was introduced, which requires web servers to provide OCSP responses to clients during the TLS handshake, making revocation checks low-cost for clients. Whether all of the players in the web's PKI are ready to support OCSP Must-Staple, however, remains still an open question.

In this paper, we take a broad look at the web's PKI and determine if all components involved --- namely, certificate authorities, web server administrators, and web browsers --- are ready to support OCSP Must-Staple. We find that each component does not yet fully support OCSP Must-Staple: OCSP responders are still not fully reliable, and most major web browsers and web server implementations do not fully support OCSP Must-Staple. On the bright side, only a few players need to take action to make it possible for web server administrators to begin relying on certificates with OCSP Must-Staple. Thus, we believe a much wider deployment of OCSP Must-Staple is an realistic and achievable goal.

Research Areas

Internet Measurement, Network Security

Related Projects

Public Key Infrastructure