Let's Encrypt: An Automated Certificate Authority to Encrypt the Entire Web.
Josh Aas, Richard Barnes, Benton Case, Zakir Durumeric, Peter Eckersley, Alan Flores-López, J. Alex Halderman et al. “Let's Encrypt: An Automated Certificate Authority to Encrypt the Entire Web.” In Proc. 2019 ACM Conference on Computer and Communications Security (CCS) pp. 2473-2487. 2019. https://dl.acm.org/doi/pdf/10.1145/3319535.3363192