Thoughts on application security, applied crypto, philosophy and logic
Another day, another urgent pronouncement on the need to transition to post-quantum cryptography ASAP: this one from the White House, in the form of an Executive Order requiring certain “high value” systems to transition to post-quantum cryptography (PQC) by the end of 2030 (for key exchange) or 2031 (for signatures). This brings forward the date [ ]
This should be old news, but I keep seeing the same mistake crop up, so I thought I’d blog about it and spread awareness. In Java, if you want to configure TLS you generally start with an SSLContext. And you get an instance of this class by calling the static method SSLContext.getInstance("TLSv1.3"), specifying the version [ ]
Java 17 introduced sealed classes, which allow you to explicitly list the allowed sub-types of an interface or base class. For example, here’s a toy example using a sealed interface and records (inner classes are implicitly added to the permitted sub-types if an explicit list is not given): If you are familiar with functional programming [ ]
I’m sure by now you’ve all read the news about Anthropic’s new “Mythos” model and its apparently “dangerous” capabilities in finding security vulnerabilities. I’m sure everyone reading this also has opinions about that. Well, here are a few of mine. Is it all just hype? Firstly, it’s tempting to dismiss the announcement as pure marketing [ ]
One of the most important lessons I’ve learned in security, is that it’s always better to push security problems back to the source as much as possible. For example, a small number of experts (hopefully) make cryptography libraries, so it’s generally better if they put in checks to prevent things like invalid curve attacks rather [ ]
I originally posted this on Mastodon, but I thought I d add it here too: “What I mean is that if you really want to understand something, the best way is to try and explain it to someone else. That forces you to sort it out in your own mind. And the more slow and dim-witted [ ]
There s a common misconception among developers that my job, as a (application) Security Engineer, is to just search for security bugs in their code. They may well have seen junior security engineers doing this kind of thing. But, although this can be useful (and is part of the job), it s not what I focus on [ ]
When I was writing Rating 26 years of Java changes, I started reflecting on the new HttpClient library in Java 11. The old way of fetching a URL was to use URL.openConnection(). This was intended to be a generic mechanism for retrieving the contents of any URL: files, web resources, FTP servers, etc. It was a [ ]
This post covers several topics around collections (sets, lists, maps/dictionaries, queues, etc) that I’d like to see someone explore more fully. To my knowledge, there are many alternative collection libraries for Java and for many other languages, but I’m not aware of any that provide support for monotonic collections. What is a monotonic collection, I [ ]
It s been a while since I ve written a pure programming post. I was recently implementing a specialist collection class that contained items of a number of different types. I needed to be able to iterate over the collection performing different actions depending on the specific type. There are lots of different ways to do this, [ ]
I first started programming Java at IBM back in 1999 as a Pre-University Employee. If I remember correctly, we had Java 1.1.8 installed at that time, but were moving to Java 1.2 (“Java 2”), which was a massive release—I remember engineers at the time grumbling that the ever-present “Java in a Nutshell” book had grown [ ]
OK, so you’ve made your JSON-over-HTTP API. Then someone told you that it’s not “really” REST unless it’s hypertext-driven. So now all your responses contain links, and you’re defining mediatypes properly and all that stuff. But I’m here to tell you that you’re still not doing it right. What you’re doing now is just “HYPE”. [ ]
Note: this post will probably only really make sense to cryptography geeks. In “When a KEM is not enough”, I described how to construct multi-recipient (public key) authenticated encryption. A naïve approach to this is vulnerable to insider forgeries: any recipient can construct a new message (to the same recipients) that appears to come from the [ ]
tl;dr: yes, contra thingamajig’s law of wotsits. Before the final nail has even been hammered on the coffin of AI, I hear the next big marketing wave is “quantum”. Quantum computing promises to speed up various useful calculations, but is also potentially catastrophic to widely-deployed public key cryptography. Shor’s algorithm for a quantum computer, if [ ]
I decided today to take a look at CloudFlare s new OAuth provider library, which they apparently coded almost entirely with Anthropic s Claude LLM: This library (including the schema documentation) was largely written with the help of Claude, the AI model by Anthropic. Claude s output was thoroughly reviewed by Cloudflare engineers with careful attention paid to security [ ]
Every programmer knows Donald Knuth’s famous quote that “premature optimization is the root of all evil”, from his 1974 Turing Award lecture (pdf). A fuller quotation of the surrounding context gives a rounder view: I am sorry to say that many people nowadays are condemning program efficiency, telling us that it is in bad taste. [ ]
Wikipedia’s definition of a digital signature is: A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature on a message gives a recipient confidence that the message came from a sender known to the recipient. —Wikipedia They also have a handy diagram of the process [ ]
I’ve been slowly reading Brian Cantwell Smith’s “The Promise of Artificial Intelligence” recently. I haven’t finished reading it yet, and like much of BCS’s writing, it’ll probably take me 3 or 4 read-throughs to really understand it, but there’s one point that I want to pick up on. It is the idea that “Good Old-Fashioned [ ]
It turns out you can encrypt more than 2^32 messages with AES-GCM with a random nonce under certain conditions. It’s still not a good idea, but you can just about do it. #cryptography
I see a lot of attempts to define encryption schemes for constrained devices with short authentication tags (e.g., 64 bits) using universal hashing. For example, there’s a proposal in CFRG at the moment for a version of AES-GCM with short tags for this kind of use-case. In my (admittedly limited) experience, these kinds of constrained [ ]
Happy new year! I’m hoping to write a few posts on here over the next few weeks, but probably exploring a few topics around AI and philosophy. If you’d prefer some more technical content around security and cryptography, then take a look at the newsletter I put out for my consulting company, Illuminated Security. The [ ]
I was just reading yet another article on REST API design guidelines. Some of it is good advice, some of it I could quibble with. But several of the rules are about how to design the path hierarchy of your API: use plural nouns, don’t use nested sub-paths unnecessarily, etc. In this article I want [ ]
For better or worse, depending on your perspective, JSON has become a dominant data format and shows no signs of being replaced any time soon. There are good reasons for that: on the face of it, it provides a very simple format with just enough features to cover a lot of use-cases with minimal feature [ ]
If you want to learn how to store passwords securely, you could do a lot worse than looking at the OWASP Password Storage Cheat Sheet. These cheat sheets are generally pretty good, and the password storage one is particularly good. The editors do a great job of keeping it up to date and incorporating the [ ]
In cryptography, the process of authenticating a user (or app/service) is known as entity authentication or identification (to distinguish it from message authentication or data origin authentication). There are lots of ways to do this. In this post I m going to talk about authentication schemes based on public key cryptography. It turns out that the [ ]
Mike Rosulek, Oregon State University. Draft of January 3, 2021. Online: The Joy of Cryptography. This is a freely-available book covering introductory material on cryptography. It’s suitable for anyone with undergraduate-level computer science knowledge. As is often the case in cryptography textbooks, there is a brief review of mathematical background in the first (or zeroth [ ]
I enjoyed Hillel Wayne’s recent newsletter about microfeatures they’d like to see in programming languages. A “microfeature” is essentially a small convenience that makes programming in that language a bit easier without fundamentally changing it. I love this idea. I’m partial to a bit of syntactic sugar, even if it can cause cancer of the [ ]
There has been a lot of discussion recently around the LastPass breach, especially with regards to the number of PBKDF2 iterations applied to the master password to derive the vault encryption key. Other people have already dissected this particular breach, but I want to more generally talk about PBKDF2 iterations and security models. (I’m not [ ]
Just a few quick notes/updates to correct some potentially inaccurate statements that are floating around on Reddit/Twitter etc: The bug only impacts Java 15 and above. The original advisory from Oracle incorrectly listed earlier versions (like 7, 8 and 11) as being impacted. They have since corrected this. Note that they now only list 17 [ ]
The long-running BBC sci-fi show Doctor Who has a recurring plot device where the Doctor manages to get out of trouble by showing an identity card which is actually completely blank. Of course, this being Doctor Who, the card is really made out of a special psychic paper , which causes the person looking at it [ ]