I've long had a soft spot for dependently-typed languages like Coq Rocq and Lean. They offer the possibility of a type system capable of encoding and enforcing arbitrarily subtle invariants. The sort of thing that, in regular languages, ends up (at best) as a comment, and which quickly gets lost as the size of the…
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Yesterday, Apple pushed a rather spooky security update for iOS that suggested that something was horribly wrong with SSL/TLS in iOS but gave no details. Since the answer is at the top of the Hacker News thread, I guess the cat's out of the bag already and we're into the misinformation-quashing stage now.
Update : Ralf wrote up some notes from his work. These now include an update themselves with information from Willem Pinckaers that suggests that the presumed Dual-EC output is exposed to the world in Juniper devices.
( These are my notes from the first half of my talk at HOPE9 last weekend. I write notes like these not as a script, but so that I have at least some words ready in my head when I'm speaking. They are more conversational and less organised than a usual blog post, so please forgive me the rough edges. )
I'll generally ignore the internet froth in a given week as much as possible, but when Her Majesty's Government starts repeating misunderstandings about TLS 1.3 it is necessary to write something, if only to have a pointer ready for when people start citing it as evidence.
We recently switched Google's two billion line repository over to BoringSSL , our fork of OpenSSL . This means that BoringSSL is now powering Chromium (on nearly all platforms), Android M and Google's production services. For the first time, the majority of Google's products are sharing a single TLS stack and making…
In 2005 and 2006, a series of significant results were published against SHA-1 [ 1 ][ 2 ][ 3 ]. These repeated break-throughs caused something of a crisis of faith as cryptographers questioned whether we knew how to build hash functions at all. After all, many hash functions from the 1990's had not aged well [ 1 ][ 2…
I've long had a soft spot for dependently-typed languages like Coq Rocq and Lean. They offer the possibility of a type system capable of encoding and enforcing arbitrarily subtle invariants. The sort of thing that, in regular languages, ends up (at best) as a comment, and which quickly gets lost as the size of the…
Security Keys are (generally) USB-connected hardware fobs that are capable of key generation and oracle signing. Websites can “enroll” a security key by asking it to generate a public key bound to an “appId” (which is limited by the browser based on the site's origin). Later, when a user wants to log in, the website…
Revocation checking is in the news again because of a large number of revocations resulting from precautionary rotations for servers affected by the OpenSSL heartbeat bug. However, revocation checking is a complex topic and there's a fair amount of misinformation around. In short, it doesn't work and you are no more…
Earlier this year, before Apple had too many goto fails and GnuTLS had too few , before everyone learnt that TLS heart-beat messages were a thing and that some bugs are really old , I started a tidy up of the OpenSSL code that we use at Google.
Last time I reviewed various security keys at a fairly superficial level: basic function, physical characteristics etc. This post considers lower-level behaviour.
ICANN is currently considering a proposal that “domains used for online financial transactions for commercial purpose should be ineligible for [WHOIS] privacy and proxy registrations” [ PDF ]. Given the vagueness around what would count as “commercial purpose” (tip jars? advertising? promoting your Kickstarter?) and…
Two interesting things in formally verified software happened recently. The big one was the release of SeL4 - a formally verified L4 microkernel. The second was much smaller, but closer to my usual scope: a paper which showed the correctness of sections of a couple of the assembly implementations of Curve25519.
I gave a talk a couple of weeks ago at the Yahoo Unconference . The conference was at the end of a particually hard week for a bunch of reasons and I fear that the talk wasn't that great. (Afterwards I got home about 3pm and pretty much slept until the following morning.) This post is a, hopefully clearer…
Security protocols often assume an accurate, local clock (e.g. TLS, Kerberos, DNSSEC and more). It's a widely accepted assumption when designing protocols but, for a lot of people, it just isn't true. We find good evidence that at least 25% of all certificate errors in Chrome are due to a bad local clock.
I've been looking at what would be needed in order to have a global view of CRLs in browsers. At the moment revocation has three problems: privacy (by asking the CA about the status of a certificate you're revealing to them what you're looking at), performance (OCSP checks take hundreds of milliseconds which adds up…
Continuous glucose monitoring has been a thing for a while. It's a probe that sits just inside your body and measures blood glucose levels frequently. Obviously this is most useful for type 1 diabetics, who need to regulate their blood glucose manually.
There's been some discussion about forward secret TLS recently, spurred, I think, by this piece from Declan McCullagh on CNET.
At this time last year, the TLS world was mostly running on RC4-SHA and AES-CBC. The Lucky 13 attack against CBC in TLS had just been published and I had spent most of January writing patches for OpenSSL and NSS to implement constant-time CBC decoding. The RC4 biases paper is still a couple of week away, but it's…
U2F/FIDO tokens (a.k.a. “Security Keys”) are a solid contender for doing something about the effectiveness of phishing and so I believe they're pretty important. I've written a fairly lengthy introduction to them previously and, as mentioned there, one concerning aspect of their design is that they permit attestation…
( These are notes that I wrote up from a talk that I gave at the National Academies Forum on Cyber Resilience . You can tell that it was in Washington, DC because of the “cyber”.
This is an opinionated, “quick-start” guide to using passkeys as a web developer. It’s hopefully broadly applicable, but one size will never fit all authentication needs and this guide ignores everything that’s optional. So take it as a worked example, but not as gospel.
(This is a write up of the talk that I gave at Velocity 2010 last Thursday. This is a joint work of myself, Nagendra Modadugu and Wan-Teh Chang.)
Starting with Chrome 13, we'll have HTTPS pins for most Google properties. This means that certificate chains for, say, https://www.google.com , must include a whitelisted public key. It's a fatal error otherwise. Credit goes to my colleague, Chris Evans, for much of this.
When a browser connects to an HTTPS site it receives signed certificates which allow it to verify that it's really connecting to the domain that it should be connecting to. In those certificates are pointers to services, run by the Certificate Authorities (CAs) that issued the certificate, that allow the browser to…
Thomas Ptacek laid out a number of arguments against DNSSEC recently (and in a follow up ). We don't fully agree on everything, but it did prompt me to write why, even if you assume DNSSEC, DANE (the standard for speaking about the intersection of TLS and DNSSEC) is not a foregone conclusion in web browsers.