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CloudFlare DNS is simple, fast and flexible

Over the past few years, the CloudFlare blog has covered a great range of different topics, drilling down into the technology we use to both protect websites from attack, and optimise them so that they load faster for visitors. One thing we haven’t spent enough time talking about so far though also happens to be […]

Killing RC4 (softly)

Back in 2011, the BEAST attack on the cipher block chaining (CBC) encryption mode used in TLS v1.0 was demonstrated. At the time the advice of experts (including our own) was to prioritize the use of RC4-based cipher suites. The BEAST vulnerability itself had already been fixed in TLS v1.1 a few years before, but […]

How the NSA (may have) put a backdoor in RSA’s cryptography: A technical primer

There has been a lot of news lately about nefarious-sounding backdoors being inserted into cryptographic standards and toolkits. One algorithm, a pseudo-random bit generator, Dual_EC_DRBG, was ratified by the National Institute of Standards and Technology (NIST) in 2007 and is attracting a lot of attention for having a potential backdoor. This is the algorithm into […]

Using CloudFlare to mix domain sharding and SPDY

Note: this post originally appeared as part of the 2013 PerfPlanet Calendar It’s common knowledge that domain sharding, where the resources in a web page are shared across different domains (or subdomains), is a good thing. It’s a good thing because browsers limit the number of connections per domain: splitting a web page across domains […]

Keeping our open source promise

Back in October I wrote a blog post about CloudFlare and open source software titled CloudFlare And Open Source Software: A Two-Way Street which detailed the many ways in which we use and support open source software. Since then we’ve pushed out quite a lot of new open source projects, as well as continuing to […]

Red October: CloudFlare’s Open Source Implementation of the Two-Man Rule

At CloudFlare, we are always looking for better ways to secure the data we’re entrusted with. This means hardening our system against outside threats such as hackers, but it also means protecting against insider threats. According to a recent Verizon report, insider threats account for around 14% of data breaches in 2013. While we perform […]

What we’ve been doing with Go

Almost two years ago CloudFlare started working with Go. What started as an experiment on one network and concurrency heavy project has turned into full, production use of Go for multiple services. Today Go is at the heart of CloudFlare’s services including handling compression for high-latency HTTP connections, our entire DNS infrastructure, SSL, load testing […]

A (Relatively Easy To Understand) Primer on Elliptic Curve Cryptography

Elliptic Curve Cryptography (ECC) is one of the most powerful but least understood types of cryptography in wide use today. At CloudFlare, we make extensive use of ECC to secure everything from our customers’ HTTPS connections to how we pass data between our data centers. Fundamentally, we believe it’s important to be able to understand […]