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Celebrating Ten Years of Encrypting the Web with Let’s Encrypt

Ten years ago, the web was a very different place. Most websites didn’t use HTTPS to protect your data. As a result, snoops could read emails or even take over accounts by stealing cookies . But a group of determined researchers and technologists from EFF and the University of Michigan were dreaming of a better world: one where every web page you visited was protected from spying and interference. Meanwhile, another group at Mozilla was working on the same dream. Those dreams led to the creation of Let’s Encrypt and tools like EFF’s Certbot, which simplify protecting websites and make browsing the web safer for everyone.  

There was one big obstacle: to deploy HTTPS and protect a website, the people running that website needed to buy and install a certificate from a certificate authority. Price was a big barrier to getting more websites on HTTPS, but the complexity of installing certificates was an even bigger one.   

In 2013, the Internet Security Research Group (ISRG) was founded , which would soon become the home of Let’s Encrypt, a certificate authority founded to help encrypt the Web. Let’s Encrypt was radical in that it provided certificates for free to anyone with a website. Let’s Encrypt also introduced a way to automate away the risk and drudgery of manually issuing and installing certificates. With the new ACME protocol , anyone with a website could run software (like EFF’s Certbot ) that combine d the steps of getting a certificate and correctly installing it.  

In the time since, Let’s Encrypt and Certbot have been a huge success, with over 250 million active certificates protecting hundreds of millions of websites.

This is a huge benefit to everyone’s online security and privacy. When you visit a website that uses HTTPS, your data is protected by encryption in transit, so nobody but you and the website operator gets to see it. That also prevents snoops from making a copy of your login cookies and taking over accounts.

The most important measure of Let’s Encrypt’s and Certbot’s successes is how much of people’s daily web browsing uses HTTPS. According to Firefox data, 78% of pages loaded use HTTPS. That’s tremendously improved from 27% in 2013 when Let’s Encrypt was founded. There’s still a lot of work to be done to get to 100%. We hope you’ll join EFF and Let’s Encrypt in celebrating the successes of ten years encrypting the web, and the anticipation of future growth and safety online.  

Related Issues

Join eff lists, discover more., related updates.

Should Caddy and Traefik Replace Certbot?

Can free and open source software projects like Caddy and Traefik eventually replace EFF’s Certbot ? Although Certbot continues to be developed, we think tools like these help offer a promising path forward in the further development of a secure and encrypted web. For some users, tools like...

Privacy Isn't Dead. Far From It.

Welcome! The fact that you’re reading this means that you probably care deeply about the issue of privacy, which warms our hearts. Unfortunately, even though you care about privacy, or perhaps because you care so much about it, you may feel that there's not much you (or anyone) can really...

The Last Mile of Encrypting the Web: 2023 Year in Review

At the start of 2023, we sunsetted the HTTPS Everywhere web extension. It encrypted browser communications with websites and made sure users benefited from the protection of HTTPS wherever possible. HTTPS Everywhere ended because all major browsers now offer the functionality to make HTTPS the default. This is due to...

EFF Launches the Tor University Challenge

SAN FRANCISCO—Electronic Frontier Foundation (EFF) on Tuesday launched the Tor University Challenge , a campaign urging higher education institutions to support free, anonymous speech by running a Tor network relay. Universities answering this call to defend private access to an uncensored web will receive prizes while helping...

Tell the UK’s House of Lords: Protect End-to-End Encryption in the Online Safety Bill

Private communication is a basic, universal right. In the online world, the best tool we have to defend this right is end-to-end encryption. End-to-end encryption ensures that governments, tech companies, social media platforms, and other groups cannot view or access our private messages, the pictures we share with family and...

eIDAS 2.0 Sets a Dangerous Precedent for Web Security

The Council of the European Union this week adopted new language for regulations governing internet systems that may put the security of your browser at greater risk.The new language affects the EU’s electronic identification, authentication and trust services (eIDAS) rules, which are supposed to enable secure online transactions across countries...

Let's Encrypt Wins Levchin Prize For Work On Internet Security

SAN FRANCISCO—Let’s Encrypt—a project of the nonprofit Internet Security Research Group (ISRG), which is supported by the Electronic Frontier Foundation (EFF) and other sponsors—won the prestigious international Levchin Prize for significant contributions to real-world cryptography.Let’s Encrypt is part of the effort to encrypt the entire internet as a...

What the Duck? Why an EU Proposal to Require "QWACs" Will Hurt Internet Security

It's become easier over the years for websites to improve their security, thanks to tools that allow more people to automate and easily set-up secure measures for web applications and the services they provide. A proposed amendment to Article 45 in the EU’s Digital Identity Framework...

We Encrypted the Web: 2021 Year in Review

In 2010 , EFF launched its campaign to encrypt the entire web —that is, move all websites from non-secure HTTP to the more secure HTTPS protocol. Over 10 years later, 2021 has brought us even closer to achieving that goal. With various measurement sources reporting over 90% of...

EU's Digital Identity Framework Endangers Browser Security

If a proposal currently before the European Parliament and Council passes, the security of HTTPS in your browser may get a lot worse. A proposed amendment to Article 45 in the EU’s Digital Identity Framework (eIDAS) would have major, adverse security effects on millions of users...

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Internet Security Research Group (ISRG)

ISRG's mission is to reduce financial, technological, and educational barriers to secure communication over the Internet.

ISRG was founded in 013 to serve as a home for public-benefit digital infrastructure projects, the first of which was the Let's Encrypt certificate authority.

ISRG is proudly sponsored by a diverse group of organizations, from small businesses and other non-profits to Fortune 100 companies. We aim to set an example for how everyone interested in a more secure Internet can work together to provide digital infrastructure for the public’s benefit. 

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Tenchi Security

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The Empirical Security Research Group (ESRG) is a research lab in the Stanford Computer Science Department that focuses on Internet security and privacy, online hate and harassment, and the spread of misinformation. We are an empirical lab — we build systems to collect global datasets, analyze data to better understand real-world behavior and problems, and architect more resiliant systems and protocols.

• Internet Security.    Real-world security outcomes are influenced by a tremendous number of factors ranging from manufacturer inventives to end-user confusion. We study how security plays out in practice and uncover weaknesses that can only be detected in the wild. We have uncovered fundamental flaws in protocols like HTTPS, SSH, and SMTP, and our work has influenced the design of TLS 1.3, the Linux random number generator, browser trust decisions, how CAs generate certificates, and how researchers notify operators of vulnerabilities.
• Hate and Harassment.    Online hate and harassment is a pernicious problem that impacts Internet users around the world. We study how hate and harassment is spread on major platforms and where current defenses fail to protect users, with the ultimate goal of developing better systems to help people protect themselves from online hate and harassment attacks.
• Misinformation.    Falsehoods, fake news, conspiracies, and misinformation are often deliberately spread in dense and complex networks across the Internet. We build large-scale systems to identify and analyze misinformation on social media, websites, and decentralized communication networks. Our work has included understanding the role of conspiracy theories in the spread of misinformation and documenting the disproportionate reliance of misinformation websites on particular Internet infrastructure providers.
• Internet Measurement.    The Internet is a constantly evolving world-wide ecosystem, composed of a myriad of services, network structures, operator configurations, and users. We build new systems and methods to collect and analyze data about the Internet at scale. Our work includes building scanners that identify unexpected Internet services and publically accessible cloud storage buckets, as well as developing a system that classifies organizations that own and operate the Internet.

Joining the Lab

Stanford students. we're always looking for stanford students who are interested in becoming involved with research we have a variety of projects that range from system and model building to data analysis and user research. we expect undergraduate and m.s. students working with the lab to commit a minimum of 8 hours of time to research every week as well as to attend weekly full lab meetings., we typically require that students have taken the introductory course in the topic area that they want to work in (e.g., cs144: introduction to computer networking , cs155: computer and network security , cs 152: trust and safety engineering , or cs229: machine learning ). please reach out to zakir durumeric or liz izhikevich to become involved. you can also browse some of our current projects on curis ., external students. we do not currently have research opportunities for students outside of stanford university, nor do we have influence over admission into stanford programs., software, datasets, and resources.

Network analysis framework that supports 100+ Gbps traffic analysis on a single server with no specialized hardware.

Fast single-packet network scanner for Internet-scale network surveys. ZMap can scan the public IPv4 address space in 45 minutes.

Stateful network scanner that efficiently completes application-layer handshakes and transcribes handshakes to JSON.

Network scanner than quickly detects and fingerprints network protocols and services running on unexpected ports.

High-speed recursive resolver that captures complete DNS resolutions and handles billions of lookups from a single server.

Certificate linter that checks for conformity with RFCs, CA/Browser Forum baseline requirements, and root store policies.

Network scanning platform that learns and predicts the locations of network services on IPv4 hosts across all 65K ports.

Stratosphere

Scanner that harnesses password generation algorithms to guess publicly accessible cloud storage buckets (e.g., S3 buckets).

Dataset of Autonomous Systems and their business categories (e.g., Internet Service Provider vs. Manufacturer).

Dataset of all hosts and services on the public Internet collected through daily Internet-wide scans of 100 protocols on 3,500 ports.

Public data repository for sharing Internet datasets collected through Internet scans, web crawls, and other large-scale measurements.

Publications

Machine-made media: monitoring the mobilization of machine-generated articles on misinformation and mainstream news websites.

• Hans W. A. Hanley and Zakir Durumeric
• International AAAI Conference on Web and Social Media (ICWSM), June 2024

Partial Mobilization: Tracking Multilingual Information Flows Amongst Russian Media Outlets and Telegram

Specious sites: tracking the spread and sway of spurious news stories at scale.

• Hans W. A. Hanley, Deepak Kumar, and Zakir Durumeric
• 45th IEEE Symposium on Security and Privacy (Oakland), May 2024

TATA: Stance Detection via Topic-Agnostic and Topic-Aware Embeddings

• The Conference on Empirical Methods in Natural Language Processing (EMNLP), December 2023

Cloud Watching: Understanding Attacks Against Cloud-Hosted Services

• Liz Izhikevich, Manda Tran, Michalis Kallitsis, Aurore Fass, and Zakir Durumeric
• ACM Internet Measurement Conference (IMC), October 2023

Stale TLS Certificates: Investigating Precarious Third-Party Access to Valid TLS Keys

• Zane Ma, Aaron Faulkenberry, Thomas Papastergiou, Zakir Durumeric, Michael Bailey, Angelos Keromytis, Fabian Monrose, and Manos Antonakakis

Democratizing LEO Satellite Network Measurement

• Liz Izhikevich, Manda Tran, Katherine Izhikevich, Gautam Akiwate, and Zakir Durumeric
• Preprint, June 2023

Twits, Toxic Tweets, and Tribal Tendencies: Trends in Politically Polarized Posts on Twitter

• Preprint, May 2023

Sub-Standards and Mal-Practices: Misinformation's Role in Insular, Polarized, and Toxic Interactions

A golden age: conspiracy theories' relationship with misinformation outlets, news media, and the wider internet.

• ACM Computer-Supported Cooperative Work And Social Computing (CSCW), October 2023

Hate Raids on Twitch: Echoes of the Past, New Modalities, and Implications for Platform Governance

• Catherine Han, Joseph Seering, Deepak Kumar, Jeff Hancock, and Zakir Durumeric
• Best Paper Award

Happenstance: Utilizing Semantic Search to Track Russian State Media Narratives about the Russo-Ukrainian War On Reddit

• International AAAI Conference on Web and Social Media (ICWSM), June 2023

"A Special Operation": A Quantitative Approach to Dissecting and Comparing Different Media Ecosystems' Coverage of the Russo-Ukrainian War

A world wide view of browsing the world wide web.

• Kimberly Ruth, Aurore Fass, Jonathan Azose, Mark Pearson, Emma Thomas, Caitlin Sadowski, and Zakir Durumeric
• ACM Internet Measurement Conference (IMC), October 2022

Toppling Top Lists: Evaluating the Accuracy of Popular Website Lists

• Kimberly Ruth, Deepak Kumar, Brandon Wang, Luke Valenta, and Zakir Durumeric

Retroactive Identification of Targeted DNS Infrastructure Hijacking

• Gautam Akiwate, Raffaele Sommese, Mattijs Jonker, Zakir Durumeric, kc Claffy, Geoffrey Voelker, and Stefan Savage

ZDNS: A Fast DNS Toolkit for Internet Measurement

• Liz Izhikevich, Gautam Akiwate, Briana Berger, Spencer Drakontaidis, Anna Ascheman, Paul Pearce, David Adrian, and Zakir Durumeric
• Community Contribution Award

Retina: Analyzing 100 GbE Traffic on Commodity Hardware

• Gerry Wan, Fengchen Gong, Tom Barbette, and Zakir Durumeric
• ACM Special Interest Group on Data Communication (SIGCOMM), August 2022

Predicting IPv4 Services Across All Ports

• Liz Izhikevich, Renata Teixeira, and Zakir Durumeric

On the Infrastructure Providers that Support Misinformation Websites

• Catherine Han, Deepak Kumar, and Zakir Durumeric
• International AAAI Conference on Web and Social Media (ICWSM), June 2022

No Calm in the Storm: Investigating QAnon Website Relationships

Asdb: a system for classifying owners of autonomous systems.

• Maya Ziv, Liz Izhikevich, Kimberly Ruth, Katherine Izhikevich, and Zakir Durumeric
• ACM Internet Measurement Conference (IMC), November 2021

Tracing Your Roots: Exploring the TLS Trust Anchor Ecosystem

• Zane Ma, James Austgen, Joshua Mason, Zakir Durumeric, and Michael Bailey

Stratosphere: Finding Vulnerable Cloud Storage Buckets

• Jack Cable, Drew Gregory, Liz Izhikevich, and Zakir Durumeric
• 24th Symposium on Research in Attacks, Intrusions and Defenses (RAID), October 2021

Designing Toxic Content Classification for a Diversity of Perspectives

• Deepak Kumar, Patrick Kelley, Sunny Consolvo, Joshua Mason, Elie Bursztein, Zakir Durumeric, Kurt Thomas, and Michael Bailey
• USENIX Symposium on Usable Privacy and Security (SOUPS), August 2021

LZR: Identifying Unexpected Internet Services

• USENIX Security Symposium , August 2021

What’s in a Name? Exploring CA Certificate Control

• Zane Ma, Joshua Mason, Manos Antonakakis, Zakir Durumeric, and Michael Bailey

An Empirical Analysis of HTTPS Configuration Security

• Camelia Simoiu, Wilson Nguyen, Zakir Durumeric
• Technical Report , 2021

SoK: Hate, Harassment, and the Changing Landscape of Online Abuse

• Kurt Thomas, Devdatta Akhawe, Michael Bailey, Elie Bursztein, Dan Boneh, Sunny Consolvo, Nicki Dell, Zakir Durumeric, Patrick Gage Kelley, Deepak Kumar, Damon McCoy, Sarah Meiklejohn, Thomas Ristenpart, and Gianluca Stringhini
• IEEE Symposium on Security and Privacy ("Oakland"), May 2021

On the Origin of Scanning: The Impact of Location on Internet-Wide Scans

• Gerry Wan, Liz Izhikevich, David Adrian, Katsunari Yoshioka, Ralph Holz, Christian Rossow, Zakir Durumeric
• ACM Internet Measurement Conference (IMC), October 2020

An Empirical Analysis of California Data Breaches

• Richard Chen, Zakir Durumeric
• Technical Report

Let's Encrypt: An Automated Certificate Authority to Encrypt the Entire Web

• Josh Aas, Richard Barnes, Benton Case, Zakir Durumeric, Peter Eckersley, Alan Flores-Lopez, J. Alex Halderman, Jacob Hoffman-Andrews, James Kasten, Eric Rescorla, Seth Schoen, Brad Warren
• ACM Conference on Computer and Communications Security (CCS), November 2019

All Things Considered: An Analysis of IoT Devices on Home Networks

• Deepak Kumar, Kelly Shen, Benton Case, Deepali Garg, Galina Alperovich, Dmitry Kuznetsov, Rajarshi Gupta, Zakir Durumeric
• USENIX Security Symposium , August 2019

Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice

• David Adrian, Karthikeyan Bhargavan, Zakir Durumeric, Pierrick Gaudry, Matthew Green, J. Alex Halderman, Nadia Heninger, Drew Springall, Emmanuel Thomé, Luke Valenta, Benjamin VanderSloot, Eric Wustrow, Santiago Zanella-Beguelin, and Paul Zimmermann
• Communications of the ACM. January 2019.

Tracking Certificate Misissuance in the Wild

• Deepak Kumar, Zhengping Wang, Matthew Hyder, Joseph Dickinson, Gabrielle Beck, David Adrian, Joshua Mason, Zakir Durumeric, J. Alex Halderman, Michael Bailey
• IEEE Symposium on Security and Privacy ("Oakland"), May 2018

Scanning the Internet for Liveness

• Shehar Bano, Philipp Richter, Mobin Javed, Srikanth Sundaresan, Zakir Durumeric, Steven Murdoch, Richard Mortier, Vern Paxson
• SIGCOMM Computer Communication Review April 2018 (CCR)
• IETF Applied Networking Research Prize (ANRP)

Target Generation for IPv6 Scanning

• Austin Murdock, Frank Li, Paul Bramsen, Zakir Durumeric, Vern Paxson
• ACM Internet Measurement Conference (IMC), November 2017

Understanding the Mirai Botnet

• Manos Antonakakis, Tim April, Michael Bailey, Matt Bernhard, Elie Bursztein, Jaime Cochran, Zakir Durumeric, J. Alex Halderman, Luca Invernizzi, Michalis Kallitsis, Deepak Kumar, Chaz Lever, Zane Ma, Joshua Mason, Damian Menscher, Chad Seaman, Nick Sullivan, Kurt Thomas, Yi Zhou
• USENIX Security Symposium (USENIX Security), August 2017

Security Challenges in an Increasingly Tangled Web

• Deepak Kumar, Zane Ma, Zakir Durumeric, Ariana Mirian, Joshua Mason,
• J. Alex Halderman, and Michael Bailey
• World Wide Web Conference (WWW), April 2017

The Danger of USB Drives

• Matthew Tischer, Zakir Durumeric, Elie Bursztein, and Michael Bailey
• IEEE Security & Privacy (S&P Magazine). March 2017.

The Security Impact of HTTPS Interception

• Zakir Durumeric, Zane Ma, Drew Springall, Richard Barnes, Nick Sullivan, Elie Bursztein, Michael Bailey, J. Alex Halderman, and Vern Paxson
• Network and Distributed System Security Symposium (NDSS), February 2017

An Internet-Wide View of ICS Devices

• Ariana Mirian, Zane Ma, David Adrian, Matthew Tischer, Thasphon Chuenchujit, Tim Yardley, Robin Berthier, Josh Mason, Zakir Durumeric, J. Alex Halderman and Michael Bailey
• IEEE Conference on Privacy, Security and Trust (PST), December 2016

Measuring the Security Harm of TLS Crypto Shortcuts

• Drew Springall, Zakir Durumeric, and J. Alex Halderman
• ACM Internet Measurement Conference (IMC), November 2016

Towards a Complete View of the Certificate Ecosystem

• Benjamin VanderSloot, Johanna Amann, Matthew Bernhard, Zakir Durumeric, Michael Bailey, and J. Alex Halderman

You’ve Got Vulnerability: Exploring Effective Vulnerability Notifications

• Frank Li, Zakir Durumeric, Jakub Czyz, Mohammad Karami, Michael Bailey, Damon McCoy, Stefan Savage, and Vern Paxson
• USENIX Security Symposium (USENIX Security), August 2016

FTP: The Forgotten Cloud

• IEEE/IFIP Conference on Dependable Systems and Networks (DSN), June 2016

Users Really Do Plug in USB Drives They Find

• Matthew Tischer, Zakir Durumeric, Sam Foster, Sunny Duan, Alec Mori, Elie Bursztein, and Michael Bailey
• IEEE Symposium on Security & Privacy ("Oakland"), May 2016

Neither Snow Nor Rain Nor MITM... An Empirical Analysis of Email Delivery Security

• Zakir Durumeric, David Adrian, Ariana Mirian, James Kasten, Kurt Thomas, Vijay Eranti, Nicholas Lidzborski, Elie Bursztein, Michael Bailey, and J. Alex Halderman
• ACM Internet Measurement Conference (IMC), October 2015
• ACM Computer and Communications Security (CCS), October 2015

Censys: A Search Engine Backed by Internet-Wide Scanning

• Zakir Durumeric, David Adrian, Ariana Mirian, Michael Bailey, and J. Alex Halderman

The Matter of Heartbleed

• Zakir Durumeric, Frank Li, James Kasten, Johanna Amann, Jethro Beekman, Mathias Payer, Nicolas Weaver, David Adrian, Vern Paxson, Michael Bailey, and J. Alex Halderman
• ACM Internet Measurement Conference (IMC), November 2014

Security Analysis of the Estonian Internet Voting System

• Drew Springall, Travis Finkenauer, Zakir Durumeric, Jason Kitcat, Harri Hursti, Margaret MacAlpine and J. Alex Halderman
• ACM Computer and Communications Security (CCS), November 2014

An Internet-Wide View of Internet-Wide Scanning

• Zakir Durumeric, Michael Bailey, and J. Alex Halderman
• USENIX Security Symposium (USENIX Security), August 2014

Zippier ZMap: Internet-Wide Scanning at 10 Gbps

• David Adrian, Zakir Durumeric, Gulshan Singh, and J. Alex Halderman
• USENIX Workshop on Offensive Technologies (WOOT), August 2014

Outsmarting Proctors with Smartwatches: A Case Study on Wearable Computing Security

• Alex Migicovsky, Zakir Durumeric, Jeff Ringenberg, and J. Alex Halderman
• Financial Cryptography and Data Security (Financial Crypto), March 2014

On the Mismanagement and Maliciousness of Networks

• Jing Zhang, Zakir Durumeric, Michael Bailey, Manish Karir, and Mingyan Liu
• Network and Distributed System Security Symposium (NDSS), February 2014

Analysis of the HTTPS Certificate Ecosystem

• Zakir Durumeric, James Kasten, Michael Bailey, and J. Alex Halderman
• ACM Internet Measurement Conference (IMC), October 2013

ZMap: Fast Internet-Wide Scanning and its Security Applications

• Zakir Durumeric, Eric Wustrow, and J. Alex Halderman
• USENIX Security Symposium (USENIX Security), August 2013

Mining Your Ps and Qs: Detection of Widespread Weak Keys in Network Devices

• Nadia Heninger, Zakir Durumeric, Eric Wustrow, and J. Alex Halderman
• USENIX Security Symposium (USENIX Security), August 2012

Memory safety for the Internet's most critical infrastructure

Initiatives, tls (rustls).

Let's get the Rustls TLS library ready to replace OpenSSL in as many projects as possible.

Linux Kernel

Let's make it possible to write memory safe drivers for the Linux kernel.

Reverse Proxy (River)

Let's make the network edge memory safe.

DNS (Hickory)

Let's create a memory safe, high performance, fully recursive DNS resolver.

AV1 (rav1d)

Let's create a memory safe AV1 decoder that delivers great performance.

Let's create a memory safe zlib compression library with great performance.

sudo/su (sudo-rs)

Let's make the utilities that mediate privileges safer.

NTP (ntpd-rs)

Let's create a memory safe NTP implementation.

Apache httpd (mod_tls)

Let's make it possible to use memory safe TLS networking in Apache httpd.

Let's make TLS and HTTP networking code in curl memory safe.

Let's improve the tools we use to bring memory safe software to the world.

From our blog

Providing official fedora linux rpm packages for ntpd-rs and sudo-rs.

Memory safe NTP and sudo are now in Fedora Linux.

Rustls Gains OpenSSL and Nginx Compatibility

Nginx users can easily switch from OpenSSL to Rustls for better security.

A Readout from Tectonics

Challenges and solutions for moving forward with memory safety for critical Internet infrastructure.

The Rustls TLS Library Adds Post-Quantum Key Exchange Support

Protecting TLS encryption keys in a post-quantum world.

White House, Craig Newmark Support Memory Safe Software

Growing attention on the solvability of memory safety.

Get Involved

Being part of ambitious work like Prossimo is easier than you might think: 100% of our funding comes from charitable donations from companies and people like you.

When you support Prossimo, you’re helping to create a future for the Web that is more memory safe and more secure - and that benefits everyone using it!

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Become a Funder

Prossimo works to connect maintainers behind the Internet's most critical pieces of software with the people and organizations who want to see Internet security move forward by adopting memory safe languages. Here's the simple framework of how Prossimo works:

• Identify an initiative that's a good fit for Prossimo
• Seek funding for the initiative
• Commence the initiative

By funding, you can support this important work!

Contact us to learn about upcoming Prossimo initiatives: [email protected]

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Exploring the landscape of network security: a comparative analysis of attack detection strategies

• Original Research
• Published: 05 May 2024

Cite this article

• P. Rajesh Kanna   ORCID: orcid.org/0000-0002-0961-3634 1 &
• P. Santhi 2  

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The field of computer networking is experiencing rapid growth, accompanied by the swift advancement of internet tools. As a result, people are becoming more aware of the importance of network security. One of the primary concerns in ensuring security is the authority over domains, and network owners are striving to establish a common language to exchange security information and respond quickly to emerging threats. Given the increasing prevalence of various types of attacks, network security has become a significant challenge in the realm of computing. To address this, a multi-level distributed approach incorporating vulnerability identification, dimensioning, and countermeasures based on attack graphs has been developed. Implementing reconfigurable virtual systems as countermeasures significantly improves attack detection and mitigates the impact of attacks. Password-based authentication, for instance, can be susceptible to password cracking techniques, social engineering attacks, or data breaches that expose user credentials. Similarly, ensuring privacy during data transmission through encryption helps protect data from unauthorized access, but it does not guarantee the prevention of other types of attacks such as malware infiltration or insider threats. This research explores various techniques to achieve effective attack detection. Multiple research methods have been utilized and evaluated to identify the most suitable approach for network security and attack detection in the context of cloud computing. The analysis and implementation of diverse research studies demonstrate that the based signature intrusion detection method outperforms others in terms of precision, recall, F-measure, accuracy, reliability, and time complexity.

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A survey on security challenges in cloud computing: issues, threats, and solutions

Survey of intrusion detection systems: techniques, datasets and challenges

A systematic literature review for network intrusion detection system (IDS)

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Rajesh Kanna, P., Santhi, P. Exploring the landscape of network security: a comparative analysis of attack detection strategies. J Ambient Intell Human Comput (2024). https://doi.org/10.1007/s12652-024-04794-y

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Kristin Berdan joins ISRG as new General Counsel

Josh Aas May 16, 2024

We are thrilled to announce that Kristin Berdan is ISRG’s new General Counsel. With her unique and varied legal career and her passion for Internet security, she is a great fit for our organization.

Kristin's journey through the legal profession has been neither linear nor conventional. With an undergraduate focus on extremist politics and terrorism, she initially pursued law school to better understand the systems and institutions that such groups challenge. This led her to a deep interest in intellectual property and international law. She received her Juris Doctor from the University of California at Davis, whose proximity to Silicon Valley led Kristin to a succession of tech-related legal roles across government, academia, and private industry.

Reflecting on her achievements, Kristin views her career as a series of opportunities to contribute positively to the world, from supporting engineers at Lawrence Berkeley National Lab to researching digital threats at Citizen Lab and UC Berkeley, and helping build Internet infrastructure at Google.

When asked about her move to ISRG, Kristin shared: “I knew of ISRG and Let's Encrypt through my previous work in Internet infrastructure, and when the position for General Counsel became available, I knew it was the perfect opportunity for me. ISRG’s commitment to reducing barriers for secure communication over the Internet aligns seamlessly with my career goals and personal values.”

Kristin’s excitement about her role is palpable, especially when discussing the projects that energize her: “I’m always excited to learn new things about how the Internet works, and this job provides me with plenty of opportunities for that! Let’s Encrypt is fascinating as Certificate Authorities are such a core element of securing Internet communications. Divvi Up is at the frontier of a new way to collect and aggregate metrics in a privacy-preserving way. And having seen firsthand the danger that memory unsafe code poses to the global Internet, I’m happy to be part of the Prossimo work that is dedicated to promoting memory safety.”

As ISRG’s first General Counsel, Kristin is confident that her work will continue to be novel and fascinating, and beneficial to the Internet being global, free, and secure for everyone. We’re so glad to have Kristin on board!

Support Our Work

ISRG is a 501(c)(3) nonprofit organization that is 100% supported through the generosity of those who share our vision for ubiquitous, open Internet security. If you'd like to support our work, please consider getting involved , donating , or encouraging your company to become a sponsor .

ITS Cybersecurity Research Program

Its research.

Cybersecurity is a serious and ongoing challenge for the transportation sector . Cyber threats to transportation systems can impact national security, public safety, and the national economy. The ITS Cybersecurity Research Program was developed in response to the urgent need to protect Intelligent Transportation Systems (ITS) from cyber-attacks.

Subordinate (Intermediate) CAs

We currently maintain four intermediates in active rotation. Subscriber certificates containing an ECDSA public key will be issued from one of the ECDSA intermediates; similarly, Subscriber certificates containing an RSA public key will be issued from one of the RSA intermediates.

All intermediate certificate Subjects have a Country field of C = US .

• Subject: O = Let's Encrypt, CN = E5
• Validity: until 2027-03-12
• Certificate details (signed by ISRG Root X2): der , pem , txt
• Certificate details (cross-signed by ISRG Root X1): der , pem , txt
• Subject: O = Let's Encrypt, CN = E6
• Subject: O = Let's Encrypt, CN = R10
• Key type: RSA 2048
• Certificate details (signed by ISRG Root X1): der , pem , txt
• Subject: O = Let's Encrypt, CN = R11

Click below for details on additional intermediates which are not part of the active issuance hierarchy:

These intermediate CAs have currently-valid certificates, but are not being issued from. We may begin issuing Subscriber certificates from them at any time, without warning.

• Subject: O = Let's Encrypt, CN = E7
• Subject: O = Let's Encrypt, CN = E8
• Subject: O = Let's Encrypt, CN = E9
• Subject: O = Let's Encrypt, CN = R12
• Subject: O = Let's Encrypt, CN = R13
• Subject: O = Let's Encrypt, CN = R14

These intermediate CAs are no longer being used to issue Subscriber certificates. Those which still have valid certificates may be producing OCSP responses and/or CRLs.

• Subject: O = Let's Encrypt, CN = E1
• Validity: until 2025-09-15
• Certificate details (signed by ISRG Root X2): crt.sh , der , pem , txt
• Subject: O = Let's Encrypt, CN = E2
• Subject: O = Let's Encrypt, CN = R3
• Certificate details (signed by ISRG Root X1): crt.sh , der , pem , txt
• Certificate details (cross-signed by IdenTrust): crt.sh , der , pem , txt
• Subject: O = Let's Encrypt, CN = R4
• Subject: O = Let's Encrypt, CN = Let's Encrypt Authority X1
• Validity: expired 2020-06-04
• Subject: O = Let's Encrypt, CN = Let's Encrypt Authority X2
• Subject: O = Let's Encrypt, CN = Let's Encrypt Authority X3
• Validity: expired 2021-10-06
• Subject: O = Let's Encrypt, CN = Let's Encrypt Authority X4

This keypair was previously used to sign OCSP responses regarding the status of Let’s Encrypt’s intermediates on behalf of Let’s Encrypt’s root, so that the root could remain safely offline. We no longer issue OCSP responses for our intermediates; we instead periodically issue CRLs from our root to convey the revocation status of our intermediates.

• Subject: O = Internet Security Research Group, CN = ISRG Root OCSP X1
• Validity: until 2025-06-10
• Certificate details (signed by ISRG Root X1): crt.sh (expired)

When an ACME client downloads a newly-issued certificate from Let’s Encrypt’s ACME API, that certificate comes as part of a “chain” that also includes one or more intermediates. Usually this chain consists of just the end-entity certificate and one intermediate, but it could contain additional intermediates. The idea is that, by presenting this whole chain of certificates to a website visitor’s browser, the browser will be able to validate the signatures all the way up to a root that browser trusts without having to download any additional intermediates.

Sometimes there’s more than one valid chain for a given certificate: for example, if an intermediate has been cross-signed, then either one of those two certificates could be the second entry, “chaining up to” either of two different roots. In this case, different website operators may want to select different chains depending on the properties that they care about the most.

Subscriber certificates with RSA public keys are issued from our RSA intermediates, which are issued only from our RSA root ISRG Root X1 (i.e. they are not cross-signed). Therefore, all RSA subscriber certificates have only a single chain available:

Subscriber certificates with ECDSA public keys are issued from our ECDSA intermediates, which are issued both (i.e. are cross-signed) from our RSA root ISRG Root X1 and our ECDSA root ISRG Root X2. Therefore we offer two chains for these certificates:

ECDSA Subcriber Cert ← ECDSA Intermediate (E5 or E6) ← ISRG Root X2

The first chain, up to ISRG Root X1, provides the greatest compatibility because that root certificate is included in the most trust stores. The second chain, up to ISRG Root X2, consumes fewer bytes of network bandwidth in each TLS handshake. We provide the first chain by default, to ensure the widest compatibility. Subscribers who wish to prioritize size over compatibility can reference their ACME client’s documentation for instructions on how to request the alternate chain (for example, certbot’s --preferred-chain flag ).

Note: This section describes Let’s Encrypt’s hierarchy as it historically has been, prior to the the changes on June 6, 2024.

Root Certificates

Our roots are kept safely offline. We issue end-entity certificates to subscribers from the intermediates in the next section. For additional compatibility as we submit our new Root X2 to various root programs, we have also cross-signed it from Root X1.

• Self-signed : der , pem , txt
• Cross-signed by DST Root CA X3 : der , pem , txt
• Cross-signed by ISRG Root X1 : der , pem , txt

We’ve set up websites to test certificates chaining to our active roots.

Intermediate Certificates

Under normal circumstances, certificates issued by Let’s Encrypt will come from “R3”, an RSA intermediate. Currently, issuance from “E1”, an ECDSA intermediate, is possible only for ECDSA subscriber keys for allowlisted accounts . In the future, issuance from “E1” will be available for everyone.

Our other intermediates (“R4” and “E2”) are reserved for disaster recovery and will only be used should we lose the ability to issue with our primary intermediates. We do not use the X1, X2, X3, and X4 intermediates anymore.

IdenTrust has cross-signed our RSA intermediates for additional compatibility.

• Signed by ISRG Root X1 : der , pem , txt
• Cross-signed by IdenTrust : der , pem , txt (Retired)
• Signed by ISRG Root X2 : der , pem , txt
• Signed by ISRG Root X2: der , pem , txt
• Cross-signed by ISRG Root X1: der , pem , txt
• Signed by ISRG Root X1: der , pem , txt
• Cross-signed by IdenTrust : der , pem , txt

Cross Signing

Intermediates.

Each of our intermediates represents a single public/private key pair. The private key of that pair generates the signature for all end-entity certificates (also known as leaf certificates), i.e. the certificates we issue for use on your server.

Our RSA intermediates are signed by ISRG Root X1. ISRG Root X1 is widely trusted at this point, but our RSA intermediates are still cross-signed by IdenTrust’s “ DST Root CA X3 ” (now called “TrustID X3 Root”) for additional client compatibility. The IdenTrust root has been around longer and thus has better compatibility with older devices and operating systems (e.g. Windows XP, Android 7). You can download “TrustID X3 Root” from IdenTrust (or, alternatively, you can download a copy from us ).

Having cross-signatures means that each of our RSA intermediates has two certificates representing the same signing key. One is signed by DST Root CA X3 and the other is signed by ISRG Root X1. The easiest way to distinguish the two is by looking at their Issuer field.

When configuring a web server, the server operator configures not only the end-entity certificate, but also a list of intermediates to help browsers verify that the end-entity certificate has a trust chain leading to a trusted root certificate. Almost all server operators will choose to serve a chain including the intermediate certificate with Subject “R3” and Issuer “ISRG Root X1”. The recommended Let’s Encrypt client software, Certbot , will make this configuration seamlessly.

Similar to intermediates, root certificates can be cross-signed, often to increase client compatibility. Our ECDSA root, ISRG Root X2 was generated in fall 2020 and is the root certificate for the ECDSA hierarchy. It is represented by two certificates: one that is self-signed and one that is signed by ISRG Root X1.

All certificates signed by the ECDSA intermediate “E1” will come with a chain including an intermediate certificate whose Subject is “ISRG Root X2” and whose Issuer is “ISRG Root X1”. Almost all server operators will choose to serve this chain as it offers the most compatibility until ISRG Root X2 is widely trusted.

OCSP Signing Certificate

This certificate is used to sign OCSP responses for the Let’s Encrypt Authority intermediates, so that we don’t need to bring the root key online in order to sign those responses. A copy of this certificate is included automatically in those OCSP responses, so Subscribers don’t need to do anything with it. It is included here for informational purposes only.

• ISRG Root OCSP X1 ( Signed by ISRG Root X1 ): der , pem , txt

Our newer intermediates do not have OCSP URLs (their revocation information is instead served via CRL), so we have not issued an OCSP Signing Cert from ISRG Root X2.

Certificate Transparency

We are dedicated to transparency in our operations and in the certificates we issue. We submit all certificates to Certificate Transparency logs as we issue them. You can view all issued Let’s Encrypt certificates via these links:

• Issued by Let’s Encrypt Authority X1
• Issued by Let’s Encrypt Authority X3
• Issued by E1
• Issued by R3

Support a more secure and privacy-respecting Web.