Enarx and Pi (and Wasm)

It’s not just Raspberry Pi, but also Macs.

A few weeks ago, I wrote a blog post entitled WebAssembly: the importance of language(s), in which I talked about how important it is for Enarx that WebAssembly supports multiple languages. We want to make it easy for as many people as possible to use Enarx. Today, we have a new release of Enarx – Elmina Castle – and with it comes something else very exciting: Raspberry Pi support. In fact, there’s loads more in this release – it’s not just Raspberry Pi, but also Macs – but I’d like to concentrate on what this means.

As of this release, you can run WebAssembly applications on your Raspberry Pi, using Enarx. Yes, that’s right: you can take your existing Raspberry Pi (as long as it’s running a 64bit kernel), and run Wasm apps with the Enarx framework.

While the Enarx framework provides the ability to deploy applications in Keeps (TEE[1] instances), one of the important features that it also brings is the ability to run applications outside these TEEs so that you can debug and test your apps. The ability to do this much more simply is what we’re announcing today.

3 reasons this is important

1. WebAssembly just got simpler

WebAssembly is very, very hot at the moment, and there’s a huge movement behind adoption of WASI, which is designed for server-based (that is, non-browser) applications which want to take advantage of all the benefits that Wasm brings – cross-architecture support, strong security model, performance and the rest.

As noted above, Enarx is about running apps within Keeps, protected within TEE instances, but access to the appropriate hardware to do this is difficult. We wanted to make it simple for people without direct access to the hardware to create and test their applications on whatever hardware they have, and lots of people have Raspberry Pis (or Macs).

Of course, some people may just want to use Enarx to run their Wasm applications, and while that’s not the main goal of the project, that’s just fine, of course!

2. Tapping the Pi dev community

The Raspberry Pi community is one of the most creative and vibrant communities out there. It’s very open source friendly, and Raspberry Pi hardware is designed to be cheap and accessible to as many people as possible. We’re very excited about allowing anyone with access to a Pi to start developing WebAssembly and deploying apps with Enarx.

The Raspberry Pi community also has a (deserved) reputation for coming up with new and unexpected uses for technology, and we’re really interested to see what new applications arise: please tell us.

3. Preparing for Arm9 Realms

Last, and far from least, is the fact that in 2021, Arm announced their CCA (Confidential Compute Architecture), coming out with the Arm9 architecture. This will allow the creation of TEEs called Realms, which we’re looking forward to supporting with Enarx. Running Enarx on existing Arm architecture (which is what powers Raspberry Pis) is an important step towards that goal. Extending Enarx Keeps beyond the x86 architecture (as embodied by the Intel SGX and AMD SEV architectures) has always been a goal of the project, and this provides a very important first step which will allow us to move much faster when chips with the appropriate capabilities start becoming available.

How do I try it on my Raspberry Pi?

First, you’ll need a Raspberry Pi running a 64bit kernel. Instructions for this are available over at the Raspberry Pi OS pages, and the good news is that the default installer can easily put this on all of the more recent hardware models.

Next, you’ll need to follow the instructions over at the Enarx installation guide. That will walk you through it, and if you have any problems, you can (and should!) report them, by chatting with the community over at our chat or by searching for/adding bug issues at our issue tracker.

We look forward to hearing how you’re doing. If you think this is cool (and we certainly do!), then please head to our main repository at https://github.com/enarx/enarx and give us a star.


1 – Trusted Execution Environments, such as Intel’s SGX and AMD’s SEV.

Image: Michael H. („Laserlicht“) / Wikimedia Commons

WebAssembly: the importance of language(s)

We provide a guide so that you can try each lanuage for yourself.

Over at Enarx, we’re preparing for another release. They’re coming every four weeks now, and we’re getting into a good rhythm. Thanks to all contributors, and also those working on streamlining the release process. It’s a complex project with lots of dependencies – some internal, and some external – and we’re still feeling our way about how best to manage it all. One thing that you will be starting to see in our documentation, and which we intend to formalise in coming releases, is support for particular languages. I don’t mean human languages (though translations of Enarx documentation into different languages, to support as diverse a community as we can, is definitely of interest), but programming languages.

Enarx is, at its heart, a way to deploy applications into different environments: specifically, Trusted Execution Environments (though we do support testing in kvm). The important word here is “execution”, because applications need a runtime in which to execute. Runtimes come in many different flavours: ELF (“Executable and Linking Format”, the main standard for Linux systems), JVM (“Java Virtual Machine”, for compiled Java classes) and PE (“Portable Executable”, used by Windows), to give but a few examples. Enarx uses WebAssembly, or, to be more exact, WASI, which you can think of as a “headless” version of WebAssembly: whereas WebAssembly was originally designed to run within browsers, WASI-compliant runtimes support server-type applications. The runtime which Enarx supports is called wasmtime, which is a Bytecode Alliance project, and written in Rust (like Enarx itself).

This is great, but (almost) nobody writes native WebAssembly code (there is actually a “human-readable” format supported by the standard, but I personally wouldn’t want to be writing in it directly!). One of the great things about WebAssembly is that it’s largely language-neutral: you can write in your favourite language and then compile your application to a “wasm” binary to be executed by the runtime (wasmtime, in our case). WebAssembly is attracting lots of attention within the computing community at the moment, and so people have created lots of different mechanisms to allow their favourite languages to create wasm binaries. There’s a curated list here, though it’s not always updated very frequently, and given the amount of interest in the space, it may be a little out of date when you visit the page. In the list, you’ll find common languages like C, C++, Rust, Golang, .Net, Python and Javascript, as well as less obvious ones like Haskell, COBOL and Scheme. Do have a look – you may be surprised to find support for your favourite “obscure” language is already started, or even quite mature.

This proliferation of languages with what we could call “compile target support” for WebAssembly is excellent news for Enarx, because it means that people writing in these languages may be able to write applications that we can run. I say may, because there’s a slight complication, which is that not all of these compile targets support WASI, which is the specific interface supported by wasmtime, and therefore by Enarx.

This is where the Enarx community has started to step in. They – we – have been creating a list of languages which do allow you to compile wasm binaries that execute under wasmtime, and therefore in Enarx. You’ll find a list over at our WebAssembly Guide and, at time of writing, it includes Rust, C++, C, Golang, Ruby, .NET, TypeScript, AssemblyScript, Grain, Zig and JavaScript[1]. You can definitely expect to see more coming in the near future. With this list, we don’t just say “you can run applications compiled from this language”, but provide a guide so that you can try each lanuage for yourself! Currently the structure of how the information is presented varies from language to language – we should probably try to regularise this – but in each case, there should be sufficient information for someone fairly familiar with the lanaguage to write a simple program and run it in Enarx.

As I noted above, not all languages with compile target support for WebAssembly will work yet, but we’re also doing “upstream” work in some cases to help particular languages get to a position where they will work by submitting patches to fix specific issues. This is an area where more involvement from the community (that means you!) can help: the more people contributing to this work, or noting how important it is to them, the quicker we’ll gain support for more languages.

And here’s where we hope to be: in upcoming releases, we want to be in a position where Enarx officially supports particular languages. What exactly that “support” entails is something we haven’t yet fully defined, but, at minimum, we hope to be able to say something like “applications written in this language using this set of capabilities/features are expected to work”, based on automated testing of “known good” code on a per-release basis. This will mean that users of Enarx will be able to have high confidence that an application working on one release will behave exactly the same on the next: a really important property for a project intended for commercial deployments.

How can you get involved? Well, the most obvious is to visit the page in our docs relating to your favourite language. Try it out, give us feedback or offer to improve the documentation if you think it needs it, or even go upstream and offer patches. If no such page exists, you could visit our chat channels and ask to see if anyone is working on support and/or create an issue requesting support, explaining why you think it’s important.

Finally, to encourage upstream developers to realise how important supporting “their” language is, you can provide a GitHub star by visiting https://enarx.dev or https://github.com/enarx/enarx. “Starring” the project is a way to register your interest, and to show the community that Enarx is something you’re interested in.


1 – Huge thanks to everyone involved in these efforts, with a special shout-out to Deepanshu Arora, who’s done lots of work in this area.

WebAssembly logo: By Carlos Baraza – Own work / https://github.com/carlosbaraza/web-assembly-logo, CC0, https://commons.wikimedia.org/w/index.php?curid=56494100

More Enarx milestones

It’s been a big month for Enarx.

It’s being a big month for Enarx. Last week, I announced that we’d released Enarx 0.3.0 (Chittorgarh Fort), with some big back-end changes, and some new functionality as well. This week, the news is that we’ve hit a couple of milestones around activity and involvement in the project.

1500 commits

The first milestone is 1500 commits to the core project repository. When you use a git-based system, each time you make a change to a file or set of files (including deleting old ones, creating new one and editing or removing sections), you create a new commit. Each commit has a rather long identifier, and its position in the project is also recorded, along with the name provided by the committer and any comments. Commit 1500 to the enarx was from Nathaniel McCallum, and entitled feat(wasmldr): add Platform API. He committed it on Saturday, 2022-03-19, and its commit number is 8ec77de0104c0f33e7dd735c245f3b4aa91bb4d2.

I should point out that this isn’t the 1500th commit to the Enarx project, but the 1500th commit to the enarx/enarx repository on GitHub. This is the core repository for the Enarx project, but there are quite a few others, some of which also have lots of commits. As an example, the enarx/enarx-shim-sgx repository ,which provides some SGX-specific capabilities within Enarx, had 968 commits at time of writing.

500 Github stars

The second milestone is 500 GitHub stars. Stars are measure of how popular a repository or project is, and you can think of them as the Github of a “like” on social media: people who are interested in it can easily click a button on the repository page to “star” it (they can “unstar” it, too, if they change their mind). We only tend to count stars on the main enarx/enarx repository, as that’s the core one for the Enarx project. The 500th star was given to the project by a GitHub user going by the username shebuel-oss, a self-described “Open Source contributor, Advocate, and Community builder”: we’re really pleased to have attracted their interest!

There’s a handy little website which allows you to track stars to a project called GitHub Star History where you can track the addition (or removal!) of stars, and compare other projects. You can check the status of Enarx whenever you’re reading by following this link, but for the purposes of this article, the important question is how did we get to 500? Here’s a graph:

Enarx GitHub star history to 500 stars

You’ll see a nice steep line towards the end which corresponds to Nick Vidal’s influence as community manager, actively working to encourage more interest and involvement, and contributions to the Enarx project.

Why do these numbers matter?

Objectively, they don’t, if I’m honest: we could equally easily have chosen a nice power of two (like 512) for the number of stars, or the year that Michelangelo started work on the statue David (1501) for the number of commits. Most humans, however like round decimal numbers, and the fact that we hit 1500 and 500 commits and stars respectively within a couple of days of each provides a nice visual symmetry.

Subjectively, there’s the fact that we get to track the growth in interest (and the acceleration in growth) and contribution via these two measurements and their historical figures. The Enarx project is doing very well by these criteria, and that means that we’re beginning to get more visibility of the project. This is good for the project, it’s good for Profian (the company Nathaniel and I founded last year to take Enarx to market) and I believe that it’s good for Confidential Computing and open source more generally.

But don’t take my word for it: come and find out about the project and get involved.

Enarx 0.3.0 (Chittorgarh Fort)

Write some applications and run them in an Enarx Keep.

I usually post on a Tuesday, but this week I wanted to wait for a significant event: the release Enarx v0.3.0, codenamed “Chittorgarh Fort”. This happened after I’d gone to bed, so I don’t feel too bad about failing to post on time. I announced Enarx nearly three years ago, in the article Announcing Enarx on the 7th May 2019. and it’s admittedly taken us a long time to get to where we are now. That’s largely because we wanted to do it right, and building up a community, creating a start-up and hiring folks with the appropriate skills is difficult. The design has evolved over time, but the core principles and core architecture are the same as when we announced the project.

You can find more information about v0.3.0 at the release page, but I thought I’d give a few details here and also briefly add to what’s on the Enarx blog about the release.

What’s Enarx?

Enarx is a deployment framework for running applications within Trusted Execution Environments (TEEs). We provide a WebAssembly runtime and – this is new functionality that we’ve started adding in this release – attestation so that you can be sure that your application is protected within a TEE instance.

What’s new in v0.3.0?

A fair amount of the development for this release has been in functionality which won’t be visible to most users, including a major rewrite of the TEE/host interface component that we call sallyport. You will, however, notice that TLS support has been added to network connections from applications within the Keep. This is transparent to the application, so “Where does the certificate come from?” I hear you ask. The answer to that is from the attestation service that’s also part of this release. We’ll be talking more about that in further releases and articles, but key to the approach we’re taking is that interactions with the service (we call it the “Steward”) is pretty much transparent to users and applications.

How can I get involved?

What can you do to get involved? Well, visit the Enarx website, look at the code and docs over at our github repositories (please star the project!), get involved in the chat. The very best thing you can do, having looked around, is to write some applications and run them in an Enarx Keep. And then tell us about your experience. If it worked first time, then wow! We’re still very much in development, but we want to amass a list of applications that are known to work within Enarx, so tell us about it. If it doesn’t work, then please also tell us about it, and have a look at our issues page to see if you’re the first person to run across this problem. If you’re not, then please add your experiences to an existing issue, but if you are, then create a new one.

Enarx isn’t production ready, but it’s absolutely ready for initial investigations (as shown by our interns, who created a set of demos for v0.2.0, curated and aided by our community manager Nick Vidal).

Why Chittorgarh Fort?

It’s worth having a look at the Wikipedia entry for the fort: it’s really something! We decided, when we started creating official releases, that we wanted to go with the fortification theme that Enarx has adopted (that’s why you deploy applications to Enarx Keeps – a keep is the safest part of a castle). We started with Alamo, then went to Balmoral Castle, and then to Chittorgarh Fort (we’re trying to go with alphabetically sequential examples as far as we can!). I suggested Chittorgarh Fort to reflect the global nature of our community, which happens to include a number of contributors from India.

Who was involved?

I liked the fact that the Enarx blog post mentioned the names of some (most?) of those involved, so I thought I’d copy the list of github account names from there, with sincere thanks:

@MikeCamel @npmccallum @haraldh @connorkuehl @lkatalin @mbestavros @wgwoods @axelsimon @ueno @ziyi-yan @ambaxter @squidboylan @blazebissar @michiboo @matt-ross16 @jyotsna-penumaka @steveeJ @greyspectrum @rvolosatovs @lilienbm @CyberEpsilon @kubkon @nickvidal @uudiin @zeenix @sagiegurari @platten @greyspectrum @bstrie @jarkkojs @definitelynobody @Deepansharora27 @mayankkumar2 @moksh-pathak


Rahultalreja11 at English Wikipedia, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Emotional about open source

Enarx is available to all, usable by all.

Around October 2019, Nathaniel McCallum and I founded the Enarx project. Well, we’d actually started it before then, but it’s around then that the main GitHub repo starts showing up, when I look at available info. In the middle of 2021, we secured funding a for a start-up (now named Profian), and since then we’ve established a team of engineers to work on the project, which is itself part of the Confidential Computing Consortium. Enarx is completely open source, and that’s really central to the project. We want (and need) the community to get involved, try it out, improve it, and use it. And, of course, if it’s not open source, you can’t trust it, and that’s really important for security.

The journey has been hard at times, and there were times when we nearly gave up on the funding, but neither Nathaniel nor I could see ourselves working on anything else – we really, truly believe that there’s something truly special going on, and we want to bring it to the world. I’m glad (and relieved) that we persevered. Why? Because last week, on Thursday, was the day that this came true for me. The occasion was OC3, a conference in Confidential Computing organised by Edgeless Systems. I was giving a talk on Understanding trust relationships for Confidential Computing, which I was looking forward to, but Nick Vidal, Community Manager for the Enarx project, also had a session earlier on. His session was entitled From zero to hero: making Confidential Computing accessible, and wasn’t really his at all: it was taken up almost entirely by interns in the project, with a brief introduction and summing up by Nick.In his introduction, Nick explained that he’d be showing several videos recorded by the interns of demos they had recorded. These demos took the Enarx project and ran applications that the (they interns) had created within Keeps, using the WebAssembly runtime provided within Enarx. The interns and their demos were:

  • TCP Echo Server (Moksh Pathak & Deepanshu Arora) – Mosksh and Deepanshu showed two demos: a ROT13 server which accepts connections, reads text from them and returns the input, ROT13ed; and a simple echo server.
  • Fibonacci number generator (Jennifer Chukwu) – a simple Fibonacci number generator running in a Keep
  • Machine learning with decision tree algorithm on Diabetes data set (Jennifer Kumar & Ajay Kumar) – implementation of Machine Learning, operating on a small dataset.
  • Zero Knowledge Proof using Bulletproof (Shraddha Inamdar) – implementation of a Zero Knowledge Proof with verification.

What is exciting about these demos is several-fold:

  1. three of them have direct real-world equivalent use cases:
    1. The ROT13 server, while simple, could be the basis for an encryption/decryptions service.
    2. the Machine Learning service is directly relevant to organisations who wish to run ML workloads in the Cloud, but need assurances that the data is confidentiality and integrity protected.
    3. the Zero Knowledge Proof demo provides an example of a primitive required for complex transaction services.
  2. none of the creators of the demos knew anything about Confidential Computing until a few months ago.
  3. none of the creators knew much – if anything – about WebAssembly before coming to the project.
  4. none of the creators is a software engineering professional (yet!). They are all young people with an interest in the field, but little experience.

What this presentation showed me is that what we’re building with Enarx (though it’s not even finished at this point) is a framework that doesn’t require expertise to use. It’s accessible to beginners, who can easily write and deploy applications with obvious value. This is what made me emotional: Enarx is available to all, usable by all. Not just security experts. Not just Confidential Computing gurus. Everyone. We always wanted to build something that would simplify access to Confidential Computing, and that’s what we, the community, have brought to the world.

I’m really passionate about this, and I’d love to encourage you to become passionate about it, too. If you’d like to know more about Enarx, and hopefully even try it yourself, here are some ways to do just that;

  • visit our website, with documentation, examples and a guide to getting started
  • join our chat and then one of our stand-ups
  • view the code over at GitHub (and please star the project: it encourages more people to get involved!)
  • read the Enarx blog
  • watch the video of the demos.

I’d like to finish this post by thanking not only the interns who created the demos, but also Nick Vidal, for the incredible (and tireless!) work he’s put into helping the interns and into growing the community. And, of course, everyone involved in the project for their efforts in getting us to where we are (and the vision to continue to the next exciting stages: subscribe to this blog for upcoming details).

Enarx 0.2.0 – Balmoral Castle

Now it’s possible to write applications that you can talk to over the network

The big news this week from the Enarx project is our latest release: 0.2.0, which is codenamed “Balmoral Castle”, to continue with our castle/fortification theme.

The big change in Enarx 0.2.0 is the addition of support for networking. Until now, there wasn’t much you could really do in an Enarx Keep, honestly: you could run an application, but all it could to for input and output was read from stdin and write to stdout or stderr. While this was enough to prove that you could write and compile applications to WebAssembly and run them, any more complex interaction with the world outside the Keep was impossible.

So, why is this big news? Well, now it’s possible to write applications that you can talk to over the network. The canonical example which we’ve provided as part of the release is a simple “echo” server, which you start in a Keep and then listens on a port for incoming connections. You make a connection (for instance using the simple command-line utility ncat), and send it a line of text. The server accepts the connection, receives the text and sends it right back you. It can handle multiple connections and will send the text back to the right one (hopefully!).

This is new functionality with Enarx 0.2.0, and the ability to use networking mirrors an important change within WASI (the WebAssembly System Interface) specification, the runtime implemented within an Enarx Keep. Specifically, WASI snapshot preview 1, released in January (2022) now supports the the ACCEPT capability on sockets. The way that WASI works with managing permissions and capabilities is carefully designed, and we (the Profian folks working on Enarx) coordinated closely with the open source WASI/Wasm community to add this in a way which is consistent with the design philosophy of the project. Once the capability was added to the snapshot, there was one more step needed before Enarx could implement support, which was that it needed to appear in wasmtime, the WebAssembly runtime we use within Keeps to allow you to run your applications. This happened last week, in wasmtime release 0.34.0, and that allowed us to make this new release of Enarx.

This may not sound very exciting … but with this in place, you start to build proper applications and micro-services. What about an HTTP server? A ROT13 “encryption” service? A chatbot? An email server? A Wordle implementation[1]? And it’s not just text that you can send over a network connection, of course. What might write to process other types of data? A timestamp server? A logging service? With a network connection, you have the ability to write any of these. Micro-services are all about accepting connections, processing the data that’s come in, and then sending out the results. All of that is possible with this new release.

What we’d love you to do is to start writing applications (using networking) and running them in Enarx. Tell us what works – even better, tell us what doesn’t by creating an issue in our github repository . Please publish examples, join our chat channels, give us a github star, get involved.

What’s coming next? Well, keep an eye on the Enarx site, but be assured that I’ll announce major news here as well. You can expect work in attestation and deployment in the near future – watch this space…


1 – at time of writing, everyone’s talking about Wordle. For those of you coming from the future (say a couple of weeks from now), you can probably ignore this example.

[Image of Edward VII at Balmoral Castle from Wikimedia].

Logs – good or bad for Confidential Computing?

I wrote a simple workload for testing. It didn’t work.

A few weeks ago, we had a conversation on one of the Enarx calls about logging. We’re at the stage now (excitingly!) where people can write applications and run them using Enarx, in an unprotected Keep, or in an SEV or SGX Keep. This is great, and almost as soon as we got to this stage, I wrote a simple workload to test it all.

It didn’t work.

This is to be expected. First, I’m really not that good a software engineer, but also, software is buggy, and this was our very first release. Everyone expects bugs, and it appeared that I’d found one. My problem was tracing where the issue lay, and whether it was in my code, or the Enarx code. I was able to rule out some possibilities by trying the application in an unprotected (“plain KVM”) Keep, and I also discovered that it ran under SEV, but not SGX. It seemed, then, that the problem might be SGX-specific. But what could I do to look any closer? Well, with very little logging available from within a Keep, there was little I could do.

Which is good. And bad.

It’s good because one of the major points about using Confidential Computing (Enarx is a Confidential Computing framework) is that you don’t want to leak information to untrusted parties. Since logs and error messages can leak lots and lots of information, you want to restrict what’s made available, and to whom. Safe operation dictates that you should make as little information available as you possibly can: preferably none.

It’s bad because there are times when (like me) you need to work out what’s gone wrong, and find out whether it’s in your code or the environment that you’re running your application in.

This is where the conversation about logging came in. We’d started talking about it before this issue came up, but this made me realise how important it was. I started writing a short blog post about it, and then stopped when I realised that there are some really complex issues to consider. That’s why this article doesn’t go into them in depth: you can find a much more detailed discussion over on the Enarx blog. But I’m not going to leave you hanging: below, you’ll find the final paragraph of the Enarx blog article. I hope it piques your interest enough to go and find out more.

In a standard cloud deployment, there is little incentive to consider strong security controls around logging and debugging, simply because the host has access not only to all communications to and from a hosted workload, but also to all the code and data associated with the workload at runtime.  For Confidential Computing workloads, the situation is very different, and designers and architects of the TEE infrastructure (e.g. the Enarx projects) and even, to a lesser extent, of potential workloads themselves, need to consider very carefully the impact of host gaining access to messages associated with the workload and the infrastructure components.  It is, realistically, infeasible to restrict all communication to levels appropriate for deployment, so it is recommended that various profiles are created which can be applied to different stages of a deployment, and whose use is carefully monitored, logged (!) and controlled by process.


Header image by philm1310 from Pixabay.

Enarx first release

Write an application, compile it to WebAssembly, and then run it in one of three Keeps types.

I was on holiday last week, and I took the opportunity not to write a blog post, but while I was sunning myself[1] at the seaside, the team did a brilliant thing: we have our first release of Enarx, and a new look for the website, to boot.

To see the new website, head over to https://enarx.dev. There, you’ll find new updated information about the project, details of how to get involved, and – here’s the big news – instructions for how to download and use Enarx. If you’re a keen Rustacean, you can also go straight to crates.io (https://crates.io/crates/enarx) and start off there. Up until now, in order to run Enarx, you’ve had to do quite a lot of low level work to get things running, run your own github branches, understand how everything fits together and manage your own development environment. This has now all changed.

This first release, version 0.1.1, is codenamed Alamo, and provides an easy way in to using Enarx. As always, it’s completely open source: you can look at every single line of our code. It doesn’t provide a full feature set, but what it does do is allow you, for the first time, to write an application, compile it to WebAssembly, and then run it in one of three Keep[2] types:

  1. KVM – this is basically a debugging Keep, in that it doesn’t provide any confidentiality or integrity protection, but it does allow you to get running and to try things even if you don’t have access to specialist hardware. A standard Linux machine should do you fine.
  2. SEV – this is a Keep using AMD’s SEV technology, specifically the newer version, SEV-SNP. This requires access to a machine which supports it[3].
  3. SGX – this is a Keep using Intel’s SGX technology. Again, this requires access to a machine which supports it[3].

The really important point here is that you’re running the same binary on each of these architectures. No recompilation for different architectures: just plain old WebAssembly[4].

Current support

There’s a lot more work to do, but what do we support at the moment?

  • running WebAssembly
  • KVM, SEV and SGX Keeps (see above)
  • stdin and stdout from/to the host – this is temporary, as the host is untrusted in the Enarx model, but until we have networking support (see below), we wanted to provide a simple way to manage input and output from a Keep.

There’s lots more to come – networking and attestation are both high on the list – but now anyone can start playing with Enarx. And, we hope, submitting enhancement and feature requests, not to mention filing bugs (we know there will be some!): to do so, hop over to https://github.com/enarx/enarx/issues.

To find out more, please head over to the website – there’s loads to see – or join us on chat channel over at https://chat.enarx.dev to find out more and get involved.


1 – it’s the British seaside, in October, so “sunning” might be a little inaccurate.

2 – a Keep is what we call a TEE instance set up for you to run an application in.

3 – we have AMD and SGX machines available for people who contribute to the project – get in touch!

4 – WebAssembly is actually rather new, but “plain old” sounds better than “vanilla”. Not my favourite ice cream flavour[5].

5 – my favourite basic ice cream flavour is strawberry. Same for milkshakes.

Enarx end-to-end complete!

We now have a fully working end-to-end proof of concept, with no smoke and mirrors.

I’ve written lots about the Enarx project, a completely open source project around deploying workloads to Trusted Execution Environments, and you can find a few of the articles here:

I have some very exciting news to announce.

A team effort

Yesterday was a huge day for the Enarx project, in that we now have a fully working end-to-end proof of concept, with no smoke and mirrors (we don’t believe in those). The engineers on the team have been working really hard on getting all of the low-level pieces in place, with support from other members on CI/CD, infrastructure, documentation, community outreach and beyond. I won’t mention everyone, as I don’t want to miss anyone out, and I also don’t have their permission, but it’s been fantastic working with everyone. We’ve been edging closer and closer to having all the main pieces ready to go, and just before Christmas/New Year we got attested AMD SEV Keeps working, with the ability to access information from that attestation within the Keep. This allowed us to move to the final step, which is creating an end-to-end client-server architecture. It is this that we got running yesterday.

I happened to be the lucky person to be able to complete this part of the puzzle, building on work by the rest of the team. I don’t have the low-level expertise that many of the team have, but my background is in client-server and peer-to-peer distributed systems, and after I started learning Rust around March 2020, I decided to see if I could do something useful for the project code base: this is my contribution to the engineering. To give you an idea of what we’ve implemented, let’s look at a simple architectural diagram of an Enarx deployment.

Simple Enarx architectural diagram

Much of the work that’s been going on has been concentrated in the Enarx runtime component, getting WebAssembly working in SGX and SEV Trusted Execution Environments, working on syscall implementations and attestation. There’s also been quite a lot of work on glue – how we transfer information around the system in a standards-compliant way (we’re using CBOR encoding throughout). The pieces that I’ve been putting together have been the Enarx client agent, the Enarx host agent (or Enarx Keep Manager) and two pieces which aren’t visible in this diagram (but are in the more detailed one below): the Enarx Keep Loader and Enarx Wasm Loader (“App loader” in the detailed view).

Detailed Enarx architectural diagram

The components

Let’s look at what these components do, and then explain exactly what we’ve achieved. The name in bold refers to the diagram, the name in italics relates to the Rust crate (and, where already merged, the github repository) associated with the component.

  • Enarx Client Agent (client) – responsible to talking to the enarx-keepmgr and requesting a Keep. It checks that the Keep is correctly set up and attested and then sends the workload (a WebAssembly package) to the enarx-wasmldr component, using HTTPS with a one-use certificate derived from the attestation process.
  • Enarx Keep Manager (enarx-keepmgr) – creates enarx-keepldr components at the request of the client, proxying communications to them from the client as required (for certain attestation flows, for instance). It is untrusted by the client.
  • Enarx Keep Loader (enarx-keepldr) – there is an enarx-keepldr per Keep, and it performs the loading of components into the Trusted Execution Environment itself. It sits outside the TEE instance, and is therefore untrusted by the client.
  • Enarx App Loader (enarx-wasmldr) – the enarx-wasmldr component resides within the TEE instance, and is therefore has confidentiality and integrity protection from the rest of the host. It receives the WebAssembly (Wasm) workload from the client component and may access secret information provisioned into the Keep during the attestation process.

Here’s the post I made to the Enarx chat #development channel yesterday to announce what we managed to achieve:

  1. client -> keepmgr: “create sev keep”
  2. keepmgr launches sev keep via systemd
  3. client -> keepmgr: “perform attestation, include this private key” (note – private key is encrypted from keepmgr)
  4. keepmgr -> keepldr: “attestation + private key”
  5. keepldr creates keep, passes private key to it
  6. wasmldr creates certificate from private key
  7. wasmldr waits for workload
  8. client sends workload of HTTPS to wasmldr
  9. wasmldr accepts workload over HTTPS
  10. wasmldr executes workload

WE HAVE A FULLY WORKING END-TO-END DEMO! Thank you everyone

What does this mean? Well, everything works! The client requests a Keep using with an AMD SEV instance, it’s created, attested, listens for an incoming connection over HTTPS, and the client sends the workload, which then executes. The workload was written in Rust and compiled to WebAssembly – it’s a real application, in other words, and not a hand-crafted piece of WebAssembly for the purposes of testing.

What’s next?

There’s lots left to do, including:

  • merging all of the code into the main repositories (I was working in a separate set to avoid undue impact on other efforts)
  • tidying it to make it more presentable (both what the demo shows and the quality of the code!)
  • add SGX support – we hope that we’re closing in on this very soon
  • make the various components production-ready (the keepmgr, for instance, doesn’t manage multiple enarx-keepldr components very well yet)
  • define the wire protocol fully (somewhere other than in my head)
  • document everything!

But most of that’s easy: it’s just engineering. 🙂

We’d love you to become involved. If you’re interested, read some of my articles, visit project home page and repositories, hang out on our chat server or watch some of our videos on YouTube. We really welcome involvement – and not just from engineers, either. Come and have a play!

Vint Cerf’s “game changer”

I’m really proud to be involved with a movement which I believe can change the way we do computing.

Today’s article is a little self-indulgent, but please bear with me, as I’m a little excited. Vint Cerf is one of a small handful of people who have a claim to being called “greats”. He’s one of the co-developers of TCP/IP protocol with Bob Kahn in 1974, and has been working on technology – much of it pretty cool technology – since then. I turned 50 recently, and if I’d achieved half of what he had by his 50th birthday, I’d be feeling more accomplished than I do right now! As well as his work in technology, he’s also an advocate for accessibility, which is something which is also dear to my heart.

What does this have to do with Alice, Eve and Bob – a security blog? Well, last week, Dark Reading[1], an influential technology security site, published a commentary piece by Cerf under its “Cloud” heading: Why Confidential Computing is a Game Changer. I could hardly have been more pleased: this is an area which I’m very excited about, and which the Enarx project, of which I’m co-founder, addresses. The Enarx project is part of the Confidential Computing Consortium (mentioned in Cerf’s article), a Linux Foundation project to increase use of confidential computing through open source projects.

So, what is confidential computing? Cerf describes it as “a breakthrough technology that encrypts data in use, while it is being processed”. He goes on to give a good description of the technology, noting that Google (his employer[2]) has recently released a product using confidential computing. Google is actually far from the first cloud service provider to do this, but it’s only fair that Cerf should mention his employer’s services from time to time: I’m going to forgive him, given how enthusiastic he is about the technology more generally. He describes it as a transformational technology which “will and should be a part of every enterprise cloud deployment”.

I agree, and it’s really exciting to see such a luminary embracing the possibilities the confidential computing presents. For those readers who aren’t aware of what it is, confidential computing allows you to keep data and processes secret in the cloud, on private servers, on the Edge, IoT, etc. – even from administrators, hypervisors and the host kernel. It uses TEEs – Trusted Execution Environments – to protect the confidentiality and integrity of the workloads (application, programs) that you want to run. If you’re not sure you trust your cloud provider, if your regulatory body won’t let you run your applications in certain places, if you want to deploy to machines which are vulnerable to attack – physical or logical – then TEEs and confidential computing can help.

You can find a more information in some of my articles:

You can always visit the Confidential Computing Consortium[3] or visit the Enarx project (links above): all of our code and documentation is open, and we’d love to see you. I’m really proud to be involved with – in fact, deeply embedded in – a movement which I believe can change the way we do computing. And really excited that someone like Vint Cerf agrees.


1 – I have no affiliation with Dark Reading, though I do recommend it to readers of this blog.

2- neither do I have any affiliation with Google or Alphabet, its parent!

3 – I am, however, a member of both the Governing Board and the Technical Advisory Council of the Confidential Computing Consortium. I’m also the Treasurer.