Monitoring TLS adoption using backbone and edge traffic

Security and privacy have become major concerns for Internet communications. In order to prevent eavesdropping and tampering a lot of Internet protocols rely the Transport Security Layer (TLS). In this paper we aim to quantify the adoption of TLS using passive traffic traces captured on a backbone and edge academic network in Japan. We monitor the evolution of five common protocols and their TLS-variants over ten years of traffic data. We found that the adoption of TLS for HTTP really started around 2012, while IMAP traffic is mostly encrypted for the last ten years. The deployment of HTTPS is mainly driven by large content providers and migrating the remaining HTTP traffic to HTTPS might require significant efforts as it concerns numerous smaller services.