Let's Encrypt is a free, automated, and open Certificate Authority brought to you by the nonprofit Internet Security Research Group (ISRG). Read all about our work in our Annual Report.
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As of the end of July 2018, the Let’s Encrypt root, ISRG Root X1, is directly trusted by Microsoft products. Our root is now trusted by all major root programs, including Microsoft, Google, Apple, Mozilla, Oracle, and Blackberry. Today’s announcement that we’re trusted by all major root programs represents a major…
Update, June 24 2016 We have confirmed that Comodo submitted Requests for Express Abandonment for all three trademark registration applications in question. We’re happy to see this positive step towards resolution, and will continue to monitor the requests as they make their way through the system. We’d like to thank…
We’re pleased to announce that we’ve received cross-signatures from IdenTrust, which means that our certificates are now trusted by all major browsers. This is a significant milestone since it means that visitors to websites using Let’s Encrypt certificates can enjoy a secure browsing experience with no special…
We’re happy to announce that Let’s Encrypt has entered Public Beta. Invitations are no longer needed in order to get free certificates from Let’s Encrypt. It’s time for the Web to take a big step forward in terms of security and privacy. We want to see HTTPS become the default. Let’s Encrypt was built to enable that…
We issued our billionth certificate on February 27, 2020. We’re going to use this big round number as an opportunity to reflect on what has changed for us, and for the Internet, leading up to this event. In particular, we want to talk about what has happened since the last time we talked about a big round number of…
Let’s Encrypt passed another major milestone by issuing our first certificate. You can see it in action here. Our cross signature is not yet in place, however this certificate is fully functional for clients with the ISRG root in their trust store. When we are cross signed, approximately a month from now, our…
Let’s Encrypt is leaving beta today. We’re also excited to announce that founding sponsors Cisco and Akamai have renewed their Platinum sponsorships with 3-year commitments, Gemalto is joining as our newest Gold sponsor, and HP Enterprise, Fastly, Duda and ReliableSite.net are our newest Silver sponsors. Since our…
Update, March 13, 2018 Wildcard certificate support is live. Let’s Encrypt will begin issuing wildcard certificates in January of 2018. Wildcard certificates are a commonly requested feature and we understand that there are some use cases where they make HTTPS deployment easier. Our hope is that offering wildcards…
On September 14, 2015, our first publicly-trusted certificate went live. We were proud that we had issued a certificate that a significant majority of clients could accept, and had done it using automated software. Of course, in retrospect this was just the first of billions of certificates. Today, Let’s Encrypt is…
Today we’d like to explain what it costs to run Let’s Encrypt. We’re doing this because we strive to be a transparent organization, we want people to have some context for their contributions to the project, and because it’s interesting. Let’s Encrypt will require about $2.9M USD to operate in 2017. We believe this is…
Update, July 10, 2023 See our new blog post for details on the September 2024 expiration of the newer ISRG Root X1 cross-sign from IdenTrust. Update, December 21, 2020 Thanks to community feedback and our wonderful partners at IdenTrust, we will be able to continue to offer service without interruption to people using…
Let’s Encrypt has reached a milestone: we’ve now issued more than 100,000,000 certificates. This number reflects at least a few things: First, it illustrates the strong demand for our services. We’d like to thank all of the sysadmins, web developers, and everyone else managing servers for prioritizing protecting your…
When Let’s Encrypt first launched, we needed to ensure that our certificates were widely trusted. To that end, we arranged to have our intermediate certificates cross-signed by IdenTrust’s DST Root CA X3. This meant that all certificates issued by those intermediates would be trusted, even while our own ISRG Root X1…
Vital personal and business information flows over the Internet more frequently than ever, and we don’t always know when it’s happening. It’s clear at this point that encrypting is something all of us should be doing. Then why don’t we use TLS (the successor to SSL) everywhere? Every browser in every device supports…
Let’s Encrypt helps to protect a huge portion of the Web by providing TLS certificates to more than 235 million websites. A database is at the heart of how Let’s Encrypt manages certificate issuance. If this database isn’t performing well enough, it can cause API errors and timeouts for our subscribers. Database…
Update: March 11, 2026 If you use Certbot, see Six-Day and IP Address Certificates Available in Certbot for details on requesting these certificates. Short-lived and IP address certificates are now generally available from Let’s Encrypt. These certificates are valid for 160 hours, just over six days. In order to get a…
Let’s Encrypt is happy to announce full support for IPv6. As IPv4 address space is exhausted, more and more people are deploying services that are only reachable via IPv6. Adding full support for IPv6 allows us to serve more people and organizations, which is important if we’re going to encrypt the entire Web. IPv6 is…
On Thursday, September 3rd, 2020, Let’s Encrypt issued six new certificates: one root, four intermediates, and one cross-sign. These new certificates are part of our larger plan to improve privacy on the web, by making ECDSA end-entity certificates widely available, and by making certificates smaller. Given that we…
Our first full year as a live CA was an exciting one. I’m incredibly proud of what our team and community accomplished during 2016. I’d like to share some thoughts about how we’ve changed, what we’ve accomplished, and what we’ve learned. At the start of 2016, Let’s Encrypt certificates had been available to the public…
Today we are announcing our intent to end Online Certificate Status Protocol (OCSP) support in favor of Certificate Revocation Lists (CRLs) as soon as possible. OCSP and CRLs are both mechanisms by which CAs can communicate certificate revocation information, but CRLs have significant advantages over OCSP. Let’s…
Let’s Encrypt had a great year in 2018. We’re now serving more than 150 million websites while maintaining a stellar security and compliance track record. Most importantly though, the Web went from 67% encrypted page loads to 77% in 2018, according to statistics from Mozilla. This is an incredible rate of change! We’d…
When we look at the general security posture of Let’s Encrypt, one of the things that worries us most is how much of the operating system and network infrastructure is written in unsafe languages like C and C++. The CA software itself is written in memory safe Golang, but from our server operating systems to our…
When you request a certificate from Let’s Encrypt, our servers validate that you control the hostnames in that certificate using ACME challenges. For subscribers who need wildcard certificates or who prefer not to expose infrastructure to the public Internet, the DNS-01 challenge type has long been the only choice…
Update: Added clarification that only the Let’s Encrypt client software is changing its name and host. The Let’s Encrypt certificate authority and associated services are not changing names or relocating. Over the next few months the Let’s Encrypt client software will transition to a new name, soon to be announced…
Let’s Encrypt is committed to a post-quantum-safe Web PKI. The path we’re planning to take is Merkle Tree Certificates (“MTCs”), a new approach that adds post-quantum authentication to the web without sacrificing the speed and reliability that have made TLS universal. This post is about these plans and why we believe…
Let’s Encrypt had a great year in 2017. We more than doubled the number of active (unexpired) certificates we service to 46 million, we just about tripled the number of unique domains we service to 61 million, and we did it all while maintaining a stellar security and compliance track record. Most importantly though…
Today we kicked off our first crowdfunding campaign with the goal of raising enough funds to cover about one month of our operations - $200,000. That amount covers the operational and engineering staff, the hardware and the software, and general operating expenses needed to securely and reliably issue and manage many…
On April 13, 2022, the Real World Crypto steering committee presented the Max Levchin Prize for Real-World Cryptography to Let’s Encrypt. The following is the speech delivered by our Executive Director, Josh Aas, upon receiving the award. We’d like to thank our community for supporting us and invite you to join us in…
Let’s Encrypt has reached a point where we’re ready to announce our launch schedule. First certificate: Week of July 27, 2015 General availability: Week of September 14, 2015 We will issue the first end entity certificates under our root under tightly controlled circumstances. No cross-signature will be in place yet…
We’re excited that support for getting and managing TLS certificates via the ACME protocol is coming to the Apache HTTP Server Project (httpd). ACME is the protocol used by Let’s Encrypt, and hopefully other Certificate Authorities in the future. We anticipate this feature will significantly aid the adoption of HTTPS…