How do you use a bearer URL?

In “Towards a standard for bearer token URLs”, I described a URL scheme that can be safely used to incorporate a bearer token (such as an OAuth access token) into a URL. That blog post concentrated on the technical details of how that would work and the security properties of the scheme. But as Tim Dierks commented on Twitter, it’s not necessarily obvious to people how you’d actually use this in practice. Who creates these URLs? How are they used and shared? In this follow-up post I’ll attempt to answer that question with a few examples of how bearer URLs could be used in practice.

The bearer URL scheme
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Towards a standard for bearer token URLs

In XSS doesn’t have to be Game Over, and earlier when discussing Can you ever (safely) include credentials in a URL?, I raised the possibility of standardising a new URL scheme that safely allows encoding a bearer token into a URL. This makes it more convenient to use lots of very fine-grained tokens rather than one token/cookie that grants access to everything, which improves security. It also makes it much easier to securely share access to individual resources, improving usability. In this post I’ll outline what such a new URL scheme would look like and the security advantages it provides over existing web authentication mechanisms. As browser vendors restrict the use of cookies, I believe there is a need for a secure replacement, and that bearer URLs are a good candidate.

Continue reading “Towards a standard for bearer token URLs”

API Security in Action is published!

I wasn’t expecting it so quickly, so it caught me a little off guard, but API Security in Action is now finally published. PDF copies are available now, with printed copies shipping by the end of the month. Kindle/ePub take a little bit longer but should be out in a few weeks time.

My own print copies will take a few weeks to ship to the UK, and I can’t wait to finally hold it in my hands. That’s a brighter ending to 2020.

At some point I’ll try and collect some thoughts about the process of writing it and my feelings with the finished product. But tonight I’ll settle for a glass (or two) of a nice red. Cheers!

API Security in Action handed over to production

After a flurry of last-minute corrections and updates in response to review feedback, my book has now been handed over to Manning’s production team. That means a few weeks of copy editing and graphics polish, then indexing and typesetting to produce the final version around October time at a guess. I’m not sure how long it then takes to print and ship, but it’s getting close!

The latest edits will be pushed out to the online early-access (MEAP) copy in the next few days, so you can read essentially the finished book online if you wish. Use the code fccmadden at checkout to get 37% off if you want to check it out. The revised material includes improving the presentation of some of the longer chapters. The material on capabilities and macaroons in chapter 9 has been significantly improved, as has chapter 11 on service-to-service API calls. Chapter 12 has been improved after expert feedback from Jean-Philippe Aumasson and his colleagues at Teserakt. Exercises have been added to chapters 6, 7, 12, and 13 too. I think these changes have really made the book much better. I hope you agree.