Eran Hammer-Lahav, the former editor of the OAuth 2.0 specification, announced the fact that he would no longer be the editor of the standard in a harshly critical blog post entitled OAuth 2.0 and the Road to Hell where he made a number of key criticisms of the specification the meat of which is excerpted below

Last month I reached the painful conclusion that I can no longer be associated with the OAuth 2.0 standard. I resigned my role as lead author and editor, withdraw my name from the specification, and left the working group. Removing my name from a document I have painstakingly labored over for three years and over two dozen drafts was not easy. Deciding to move on from an effort I have led for over five years was agonizing.

There wasn’t a single problem or incident I can point to in order to explain such an extreme move. This is a case of death by a thousand cuts, and as the work was winding down, I’ve found myself reflecting more and more on what we actually accomplished. At the end, I reached the conclusion that OAuth 2.0 is a bad protocol. WS-* bad. It is bad enough that I no longer want to be associated with it. It is the biggest professional disappointment of my career.

All the hard fought compromises on the mailing list, in meetings, in special design committees, and in back channels resulted in a specification that fails to deliver its two main goals – security and interoperability. In fact, one of the compromises was to rename it from a protocol to a framework, and another to add a disclaimer that warns that the specification is unlike to produce interoperable implementations.

When compared with OAuth 1.0, the 2.0 specification is more complex, less interoperable, less useful, more incomplete, and most importantly, less secure.

To be clear, OAuth 2.0 at the hand of a developer with deep understanding of web security will likely result is a secure implementation. However, at the hands of most developers – as has been the experience from the past two years – 2.0 is likely to produce insecure implementations.

Given that I’ve been professionally associated with OAuth 2.0 over the past few years from using OAuth 2.0 as the auth method for SkyDrive APIs to acting as an advisor for the native support of OAuth 2.0 style protocols in the Web Authentication Broker in Windows 8, I thought it would be useful to provide some perspective on what Eran has written as an implementer and user of the protocol.

The Good: Easier to work with than OAuth 1.0

I’ve been a big fan of web technologies for a fairly long time. The great thing about the web is that it is the ultimate distributed system and you cannot make assumptions about any of the clients accessing your service as people have tended to do in the enterprisey world past. This encourages technologies to be as simple as possible to reduce the causes of friction as much as possible. This has led to the rise of drop dead simple protocols like HTTP and data formats like JSON.

One of the big challenges with OAuth 1.0 is that it pushed a fairly complex and fragile set of logic on app developers who were working with the protocol. This blog post from the Twitter platform team on the most complicated feature in their API bears this out

Ask a developer what the most complicated part of working with the Twitter API is, and there's a very good chance that they'll say OAuth. Anyone who has ever written code to calculate a request signature understands that there are several precise steps, each of which must be executed perfectly, in order to come up with the correct value.

One of the points of our acting on your feedback post was that we were looking for ways to improve the OAuth experience.

Given that there were over 750,000 registered Twitter developers last year, this is a lot of pain to spread out across their ecosystem. OAuth 2.0 greatly simplifies the interaction model between clients and servers by eliminating the requirement to use signed request signatures as part of the authentication and authorization process.


The Bad: It’s a framework not a protocol

The latest draft of the OAuth 2.0 specification has the following disclaimer about interoperability

OAuth 2.0 provides a rich authorization framework with well-defined security properties.  However, as a rich and highly extensible framework with any optional components, on its own, this specification is likely to produce a wide range of non-interoperable implementations.

In addition, this specification leaves a few required components partially or fully undefined (e.g. client registration, authorization server capabilities, endpoint discovery).  Without these components, clients must be manually and specifically configured against a specific authorization server and resource server in order to interoperate.

What this means in practice for developers is that learning how one OAuth 2.0 implementation works is unlikely to help you figure out how another compliant one behaves given the degree of latitude that implementers have. Thus the likelihood of being able to take the authentication/authorization code you wrote with a standard library like DotNetOpenAuth against one OAuth 2.0 implementation and then pointing it at a different one by only changing a few URLs then expecting things to work is extremely low.

In practice I expect this to not be as problematic as it sounds on paper simply because at the end of the day authentication and authorization is a small part of any API story. In general, most people will still get the Facebook SDK, Live SDK, Google Drive SDK, etc of their target platform to build their apps and it is never going to be true that those will be portable between services. For services that don’t provide multiple SDKs it is still true that the rest of the APIs will be so different that the fact that the developer’s auth code has to change will not be as big of a deal to the developer.

That said, it is unfortunate that once cannot count on a degree of predictability across OAuth 2.0 implementations.

The Ugly: Making the right choices is left as an exercise for the reader

The biggest whammy in the OAuth 2.0 specification which Eran implies is the reason he decided to quit is hinted at in the end of the aforementioned disclaimer

This framework was designed with the clear expectation that future work will define prescriptive profiles and extensions necessary to achieve full web-scale interoperability.

This implies that there are a bunch of best practices in utilizing a subset of the protocol (i.e. prescriptive profiles) that are yet to be defined. As Eran said in his post, here is a list of places where there are no guidelines in the spec

  • No required token type
  • No agreement on the goals of an HMAC-enabled token type
  • No requirement to implement token expiration
  • No guidance on token string size, or any value for that matter
  • No strict requirement for registration
  • Loose client type definition
  • Lack of clear client security properties
  • No required grant types
  • No guidance on the suitability or applicability of grant types
  • No useful support for native applications (but lots of lip service)
  • No required client authentication method
  • No limits on extensions

There are a number of places where it would be a bad idea if an implementer decided not to implement a feature without considering the security implications such as token expiration. In my day job, I’ve also been bitten by the lack of guidance on token string sizes with some of our partners making assumptions about token size that later turned out to be inaccurate which led to scrambling on both sides.

My advice for people considering implementing OAuth 2.0 on their service would be to ensure there is a security review of whatever subset of the features you are implementing before deploying the service at large. If you can’t afford or don’t have security people on staff then at the minimum I’d recommend picking one of the big guys (e.g. Google, Facebook or Microsoft) and implementing the same features that they have since they have people on staff whose job is to figure out the secure combination of OAuth 2.0 features to implement as opposed to picking and choosing without a frame of reference.

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Categories: Web Development

July 15, 2012
@ 11:04 PM

A few weeks ago Dalton Caldwell, founder of imeem and Picplz, wrote a well received blog post titled What Twitter could have been where he laments the fact that Twitter hasn’t fulfilled some of the early promise developers saw in it as a platform. Specifically he writes

Perhaps you think that Twitter today is a really cool and powerful company. Well, it is. But that doesn’t mean that it couldn’t have been much, much more. I believe an API-centric Twitter could have enabled an ecosystem far more powerful than what Facebook is today. Perhaps you think that the API-centric model would have never worked, and that if the ad guys wouldn’t have won, Twitter would not be alive today. Maybe. But is the service we think of as Twitter today really the Twitter from a few years ago living up to its full potential? Did all of the man-hours of brilliant engineers, product people and designers, and hundreds of millions of VC dollars really turn into, well, this?

His blog post struck a chord with developers which made Dalton follow it up with another blog post titled announcing an audacious proposal as well as launching the Dalton’s proposal is as follows

I believe so deeply in the importance of having a financially sustainable realtime feed API & service that I am going to refocus to become exactly that. I have the experience, vision, infrastructure and team to do it. Additionally, we already have much of this built: a polished native iOS app, a robust technical infrastructure currently capable of handing ~200MM API calls per day with no code changes, and a developer-facing API provisioning, documentation and analytics system. This isn’t vaporware.

To manifest this grand vision, we are officially launching a Kickstarter-esque campaign. We will only accept money for this financially sustainable, ad-free service if we hit what I believe is critical mass. I am defining minimum critical mass as $500,000, which is roughly equivalent to ~10,000 backers.

As can be expected as someone who’s worked on software as both an API client and platform provider of APIs, I have a few thoughts on this topic. So let’s start from the beginning.

The Promise of Twitter Annotations

About two years ago, Twitter CEO Dick Costolo wrote an expansive “state of the union” style blog post about the Twitter platform. Besides describing the state of the Twitter platform at the time it also set forth the direction the platform intended to go in and made a set of promises about how Twitter saw its role relative to its developer ecosystem. Dick wrote

To foster this real-time open information platform, we provide a short-format publish/subscribe network and access points to that network such as, and several Twitter-branded mobile clients for iPhone, BlackBerry, and Android devices. We also provide a complete API into the functions of the network so that others may create access points. We manage the integrity and relevance of the content in the network in the form of the timeline and we will continue to spend a great deal of time and money fostering user delight and satisfaction. Finally, we are responsible for the extensibility of the network to enable innovations that range from Annotations and Geo-Location to headers that can route support tickets for companies. There are over 100,000 applications leveraging the Twitter API, and we expect that to grow significantly with the expansion of the platform via Annotations in the coming months.

There was a lot of excitement in the industry about Twitter Annotations both from developers as well as the usual suspects in the tech press like TechCrunch and ReadWriteWeb. Blog posts such as How Twitter Annotations Could Bring the Real-Time and Semantic Web Together show how excited some developers were by the possibilities presented by the technology. For those who aren’t familiar with the concept, annotations were supposed to be the way to attach arbitrary metadata to a tweet beyond the well-known 140 characters. Below is a screenshot from a Twitter presentation showing this concept visually

Although it’s been two years since the Twitter Annotations was supposed to begin testing this feature has never been released nor has it talked about by the Twitter Platform team in recent months. Many believe that Twitter Annotations will never be released due to a changing of the guard within Twitter which is hinted at in Dalton Caldwell’s What Twitter could have been post

As I understand, a hugely divisive internal debate occurred among Twitter employees around this time. One camp wanted to build the entire business around their realtime API. In this scenario, Twitter would have turned into something like a realtime cloud API company. The other camp looked at Google’s advertising model for inspiration, and decided that building their own version of AdWords would be the right way to go.

As you likely already know, the advertising group won that battle, and many of the open API people left the company.

It is this seeming change in direction that Dalton has seized on to create


Why Twitter Annotations was a Difficult Promise to Make

I have no idea what went on within Twitter but as someone who has built both platforms and API clients the challenges in delivering a feature such as Twitter Annotations seem quite obvious to me. A big problem when delivering a platform as part of an end user facing service is that there are often trade offs one has to make at the expense of the other. Doing things that make end users happy may end up ticking off people who’ve built businesses on your platform (e.g. layoffs caused by Google Panda update, companies losing customers overnight after launch of Facebook's timeline, etc). On the other hand, doing things that make developers happy can create suboptimal user experiences such as the “openness” of Android as a platform making it a haven for mobile malware.

The challenge with Twitter Annotations is that it threw user experience consistency out of the Window. Imagine that the tweet shown in the image above was created by Dare’s Awesome Twitter App which allows users to “attach” a TV episode from a source like Hulu or Netflix into the app before they tweet. Now in Dare’s Awesome Twitter App, the user sees their tweet an an inline experience where they can consume the video inline similar to what Twitter calls Expanded Tweets today. However the user’s friends who are using the Twitter website or other Twitter apps just see 140 characters. You can imagine that apps would then compete on how many annotations they supported and creating new interesting annotations. This is effectively what happened with RSS and a variety of RSS extensions with no RSS reader supporting the full gamut of extensions. Heck, I supported more RSS extensions in RSS Bandit in 2009 than Google Reader does today.

This cacophony of Annotations would have meant that not only would there no longer be such a thing as a consistent Twitter experience but Twitter itself would be on an eternal treadmill of supporting various annotations as they were introduced into the ecosystem by various clients and content producers.

Secondly, the ability to put arbitrary machine readable content in tweets would have made Twitter an attractive mechanism as a “free” publish-subscribe infrastructure of all manner of apps and devices. Instead of building a push notification system to communicate with client apps or devices, an enterprising developer could just create a special Twitter account and have all the end points connect to that. The notion of Twitter controlled botnets and the rise of home appliances connected to Twitter are all indicative that there is some demand for this capability. If this content not intended for humans ever becomes a large chunk of the data flowing through Twitter, how to monetize it will be extremely challenging. Charging people for using Twitter in this way isn’t easy since it isn’t clear how you differentiate a 20,000 machine botnet from a moderately popular Internet celebrity with a lot of fans who mostly lurk on Twitter.

I have no idea if Twitter ever plans to ship Annotations but if they do I’d be very interested to see how they would solve the two problems mentioned above.

Challenges Facing as a Consumer Service

Now that we’ve talked about Twitter Annotations, let’s look at what plans to deliver to address the demand that has yet to be fulfilled by the promise of Twitter Annotations. From we learn the product that is intended to be delivered is

OK, great, but what exactly is this product you will be delivering?

As a member, you'll have a new social graph and real-time feed that you access from an mobile application or website. At first, the user experience will be very similar to what Twitter was like before it turned into a media company. On a forward basis, we will focus on expanding our core experience by nurturing a powerful ecosystem based on 3rd-party developer built "apps". This is why we think the name "" is appropriate for this service.

From a developer perspective, you will be able to read and write to a Twitter-like API. Developers behaving in good faith will have free reign to build alternate UIs, new business models of their own, and whatever they can dream up.

As this project progresses, we will be collaborating with you, our backers, while sharing and iterating screenshots of the app, API documentation, and more. There are quite a few technical improvements to existing APIs that we would like to see in the API. For example, longer message character limits, RSS feeds, and rich annotations support.

In short it intends to be a Twitter clone with a more expansive API policy than Twitter. The key problem facing is that as a social graph based services it will suffer from the curse of network effects. Social apps need to cross a particular threshold of people on the service before they are useful and once they cross that threshold it often leads to a “winner-take-all” dynamic where similar sites with smaller users bleed users to the dominant service since everyone is on the dominant service. This is how Facebook killed MySpace & Bebo and Twitter killed Pownce & Jaiku. will need to differentiate itself more than just being “open version of popular social network”. Services like and Diaspora have tried and failed to make a dent with that approach while fresh approaches to the same old social graph and news feed like Pinterest and Instagram have grown by leaps and bounds.

A bigger challenge is the implication that it wants to be a paid social network. As I mentioned earlier, social graph based services live and die by network effects. The more people that use them the more useful they get for their members. Charging money for an online service is an easy way to reduce your target audience by at least an order of magnitude (i.e. reduce your target audience by at least 90%). As an end user, I don’t see the value of joining a Twitter-clone populated by people who could afford $50 a year as opposed to joining a free service like Facebook, Twitter or even Google+.

Challenges Facing as a Developer Platform

As a developer it isn’t clear to me what I’m expected to get out of The question on how they came up with their pricing tiers is answered thusly

Additionally, there are several comps of users being willing to pay roughly this amount for services that are deeply valuable, trustworthy and dependable. For instance, Dropbox charges $10 and up per month, Evernote charges $5 and up per month, Github charges $7 and up per month.

The developer price is inspired by the amount charged by the Apple Developer Program, $99. We think this demonstrates that developers are willing to pay for access to a high quality development platform.

I’ve already mentioned above that network effects are working against as a popular consumer service. The thought of spending $50 a year to target less users than I can by building apps on Facebook or Twitter’s platforms doesn’t sound logical to me. The leaves using as a low cost publish-subscribe mechanism for various apps or devices I deploy. This is potentially interesting but I’d need to get more data before I can tell just how interesting it could be. For example, there is a bunch of talk about claiming your Twitter handle and other things which makes it sound like developers only get a single account on the service. True developer friendliness for this type of service would include disclosure on how one could programmatically create and manage nodes in the social graph (aka accounts in the system).

At the end of the day although there is a lot of persuasive writing on, there’s just not enough to explain why it will be a platform that will provide me enough value as a developer for me to part with my hard earned $50. The comparison to Apple’s developer program is rich though. Apple has given developers five billion reasons why paying them $99 a year is worth it, we haven’t gotten one good one from

That said, I wish Dalton luck on this project. Props to anyone who can pick himself up and continue to build new things after what he went through with imeem and PicPlz.

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Categories: Platforms

I read an interesting blog post by Steven Levy titled Google Glass Team: ‘Wearable Computing Will Be the Norm’ with an interview with the Project Glass team which contains the following excerpt

Wired: Do you think this kind of technology will eventually be as common as smart phones are now?

Lee: Yes. It’s my expectation that in three to five years it will actually look unusual and awkward when we view someone holding an object in their hand and looking down at it. Wearable computing will become the norm.

The above reminds me of the Bill Gates quote, “there's a tendency to overestimate how much things will change in two years and underestimate how much change will occur over 10 years”. Coincidentally the past week has been full of retrospectives on the eve of the fifth anniversary of the iPhone. The iPhone has been a great example of how we can both overestimate and underestimate the impact of a technology. When the iPhone was announced as the convergence of an iPod, a phone and an internet mobile communicator the most forward thinking assumptions were that the majority of the Apple faithful who bought iPods would be people who bought iPhones and this would head off the demise of the iPod/MP3 player market category.

Five years later, the iPhone has effectively reshaped the computing industry. The majority of tech news today can be connected back to companies still dealing with the fallout of the creation of the iPhone and it’s progeny, the iPad. Entire categories of products across multiple industries have been made obsolete (or at least redundant) from yellow pages and paper maps to PDAs, point-and-shoot cameras and netbooks. This is in addition to the sociological changes that have been wrought (e.g. some children now think a magazine is a broken iPad). The most shocking change as a techie has been watching usage and growth of the World Wide Web being replaced by usage of mobile apps. No one really anticipated or predicted this five years ago.

Wearable computing will follow a similar path. It is unlikely that within a year or two of products like Project Glass coming to market that people will stop using smartphones especially since there are many uses for the ubiquitous smartphone that Project Glass hasn’t tried to address (e.g. playing Angry Birds or Fruit Ninja at the doctor’s office while waiting for your appointment). However it is quite clear that in our lifetime there will be the ability to put together scenarios that would have seemed far fetched for science fiction just a few years ago. It will one day be possible to look up the Facebook profile or future equivalent of anyone you meet at a bar, business meeting or on the street without the person being none the wiser simply by looking at them. Most of the technology to do this already exists, it just isn’t in a portable form factor. That is just one scenario that not only will be possible but will be commonplace with products like Project Glass in the future.

Focusing on Project Glass making smartphones obsolete is like focusing on the fact that the iPhone made iPod competitors like the Creative Zen Vision obsolete. Even if it did, that was not the interesting impact. As a software professional, it is interesting to ask yourself whether your product or business will be one of those obsoleted by this technology or empowered by it. Using analogies from the iPhone era, will you be RIM or will you be Instagram?

PS: I have to wonder what Apple thinks of all of this. When I look at the image below, I see a clunky and obtrusive piece of headgear that I can imagine makes Jonathan Ive roll his eyes and think he could do much better. Given Apple’s mantra is “If you don’t cannibalize yourself, someone else will” I expect this space to be very interesting over the next ten years.

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Categories: Technology