Let's Encrypt is a free, open and automated certificate authority (CA) provided as a service by the Internet Security Research Group (ISRG).
Let's Encrypt is designed to simplify the acquisition of SSL/TLS digital certificates proving a site’s authenticity, while also providing encryption. Its automated processes will also help reduce page errors due to out of date certificates.
Using a protocol called Automated Certificate Management Environment (ACME), Let's Encrypt simplifies through automation. All of the processes involved in providing proof of control for a website such as obtaining, renewing and revoking certificates, are automated. With a simple click (or command methods), HTTPS security can be enabled for any site.
The basics of Let’s Encrypt:
- Domain name owners can obtain trusted certificates for their sites free of charge.
- Through the interaction with the CA, server software can obtain a certificate, securely configure it and automatically manage renewal.
- Let’s Encrypt is designed to serve as a platform for promoting TLS (Transport Layer Security) best practices.
- Information about all certificates issued or revoked will be made publicly available.
- The ACME protocol will also be made publicly available as an open standard.
Let’s Encrypt is hosted by the Linux Foundation. Project sponsors include the Mozilla Foundation, IdenTrust, Akamai, Cisco, the Electronic Frontier Foundation (EFF) and Automattic. The project is part of a long-term goal to encrypt the entirety of the web.
See a presentation on Let's Encrypt by the EFF: