The Quantum Threat Most of today’s cryptography is designed to be secure against an adversary with enormous amounts of computational power. This means estimating how much work certain computations (such as factoring a number, or finding a discrete logarithm) require, and choosing cryptographic parameters based on our best estimate of how much work would be […]
Tag Archives: tls
High-reliability OCSP stapling and why it matters
At Cloudflare our focus is making the internet faster and more secure. Today we are announcing a new enhancement to our HTTPS service: High-Reliability OCSP stapling. This feature is a step towards enabling an important security feature on the web: certificate revocation checking. Reliable OCSP stapling also improves connection times by up to 30% in […]
Introducing TLS with Client Authentication
In a traditional TLS handshake, the client authenticates the server, and the server doesn’t know too much about the client. However, starting now, Cloudflare is offering enterprise customers TLS with client authentication, meaning that the server additionally authenticates that the client connecting to it is authorized to connect. TLS Client Authentication is useful in cases […]
Introducing Zero Round Trip Time Resumption (0-RTT)
Cloudflare’s mission is to help build a faster and more secure Internet. Over the last several years, the Internet Engineering Task Force (IETF) has been working on a new version of TLS, the protocol that powers the secure web. Last September, Cloudflare was the first service provider to enable people to use this new version […]
TLS 1.3 explained by the Cloudflare Crypto Team at 33c3
Nick Sullivan and I gave a talk about TLS 1.3 at 33c3, the latest Chaos Communication Congress. The congress, attended by more that 13,000 hackers in Hamburg, has been one of the hallmark events of the security community for more than 30 years. You can watch the recording below, or download it in multiple formats […]
TLS nonce-nse
One of the base principles of cryptography is that you can’t just encrypt multiple messages with the same key. At the very least, what will happen is that two messages that have identical plaintext will also have identical ciphertext, which is a dangerous leak. (This is similar to why you can’t encrypt blocks with ECB.) […]
An overview of TLS 1.3 and Q&A
The CloudFlare London office hosts weekly internal Tech Talks (with free lunch picked by the speaker). My recent one was an explanation of the latest version of TLS, 1.3, how it works and why it’s faster and safer. You can watch the complete talk below or just read my summarized transcript. The Q&A session is […]
Yet Another Padding Oracle in OpenSSL CBC Ciphersuites
Yesterday a new vulnerability has been announced in OpenSSL/LibreSSL. A padding oracle in CBC mode decryption, to be precise. Just like Lucky13. Actually, it’s in the code that fixes Lucky13. It was found by Juraj Somorovsky using a tool he developed called TLS-Attacker. Like in the “old days”, it has no name except CVE-2016-2107. (I […]
Introducing CloudFlare Origin CA
Free and performant encryption to the origin for CloudFlare customers In the fall of 2014 CloudFlare launched Universal SSL and doubled the number of sites on the Internet accessible via HTTPS. In just a few days we issued certificates protecting millions of our customers’ domains and became the easiest way to secure your website with […]
Beware of Unverified TLS Certificates in PHP & Python
Web developers today rely on various third-party APIs. For example, these APIs allow you to accept credit card payments, integrate a social network with your website, or clear your CDN’s cache. The HTTPS protocol is used to secure the connection with the API server. However, if your web app doesn’t verify the TLS certificate, aRead […]
