Google Research

HTTPS Adoption in the Longtail

Google and UC San Diego (2018)


HTTPS is widely acknowledged as a pillar of modern web security. However, while much attention focuses on the value delivered by protocol improvements, the benefit of these advances is gated by the breadth of their adoption. Thus, while the majority of web pages visited benefit from the confidentiality and integrity guarantees of HTTPS, this is contradictorily due to a minority of popular sites currently supporting the protocol. In this paper written in April 2018, we explore factors of HTTPS adoption on web sites more broadly. We analyze attributes of the Alexa top one million sites in August 2017 and categorize them into popular and “longtail” sites, in an effort to identify points of leverage which offer promise for driving further adoption of HTTPS. We find that hosting provider use and cost are factors that correlate with HTTPS deployment, while other promising indicators—such as site age, site freshness, and server software choice—provide ambiguous signals and are unlikely to offer useful points of influence.

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