Let’s Encrypt 是免费的Https安全证书签发机构(CA)，目的在于向全球所有网站提供加密访问（Https），以保证网络传输的安全性和保密性。
Let’s Encrypt 今日起已经开放ACME v2.0的正式SSL证书申请服务， 对于子域名较多的站长来说可以直接申请Let’s Encrypt的通配符SSL证书，不必为每个子域名单独的申请SSL证书，从而更方便的管理站点SSL证书，对我们来说都是一个好消息。
We’re pleased to announce that ACMEv2 and wildcard certificate support is live! With today’s new features we’re continuing to break down barriers for HTTPS adoption across the Web by making it even easier for every website to get and manage certificates.
ACMEv21.8k is an updated version of our ACME protocol which has gone through the IETF standards process, taking into account feedback from industry experts and other organizations that might want to use the ACME protocol for certificate issuance and management some day.
Wildcard certificates2.1k allow you to secure all subdomains of a domain with a single certificate. Wildcard certificates can make certificate management easier in some cases, and we want to address those cases in order to help get the Web to 100% HTTPS. We still recommend non-wildcard certificates for most use cases.
Wildcard certificates are only available via ACMEv2. In order to use ACMEv2 for wildcard or non-wildcard certificates you’ll need a client that has been updated to support ACMEv23.8k. It is our intent to transition all clients and subscribers to ACMEv2, though we have not set an end-of-life date for our ACMEv1 API yet.
Additionally, wildcard domains must be validated using the DNS-01 challenge type. This means that you’ll need to modify DNS TXT records in order to demonstrate control over a domain for the purpose of obtaining a wildcard certificate.
For more technical information about ACMEv2 and wildcard certificates, see this post4.1k.
We’re excited about the prospect of a 100% HTTPS Web and we’re working hard to get there. As a non-profit organization, we need strong support from our community so please consider getting involved163, making a donation183, or sponsoring115 Let’s Encrypt.
FreeSSL.org 是一个免费提供 HTTPS 证书申请、HTTPS 证书管理和 HTTPS 证书到期提醒服务的网站，旨在推进 HTTPS 证书的普及与应用，简化证书申请的流程。其中包含了Let’s Encrypt 与 TrustAsia 两个证书在线申请。