April 3, 2008
@ 06:10 AM

Earlier today I hopefully gave a somewhat reasonable, simple answer to the question "What is a Claim?" Let's try the same with "Token":

In the WS-* security world, "Token" is really just a another name the security geniuses decided to use for "Handy package for all sorts of security stuff". The most popular type of token is the SAML (just say "samel") token. If the ladies and gentlemen designing and writing security platform infrastructure and frameworks are doing a good job you might want to know about the existence of such a thing, but otherwise be blissfully ignorant of all the gory details.

Tokens are meant to be a thing that you need to know about in much the same way you need to know about ... ummm... rebate coupons you can cut out of your local newspaper or all those funny books that you get in the mail. I have really no idea how the accounting works behind the scenes between the manufacturers and the stores, but it really doesn't interest me much, either. What matters to me is that we get $4 off that jumbo pack of diapers and we go through a lot of those these days with a 9 month old baby here at home. We cut out the coupon, present it at the store, four bucks saved. Works for me.

A token is the same kind of deal. You go to some (security) service, get a token, and present that token to some other service. The other service takes a good look at the token and figures whether it 'trusts' the token issuer and might then do some further inspection; if all is well you get four bucks off. Or you get to do the thing you want to do at the service. The latter is more likely, but I liked the idea for a moment.

Remember when I mentioned the surprising fact that people lie from time to time when I wrote about claims? Well, that's where tokens come in. The security stuff in a token is there to keep people honest and to make 'assertions' about claims. The security dudes and dudettes will say "Err, that's not the whole story", but for me it's good enough. It's actually pretty common (that'll be their objection) that there are tokens that don't carry any claims and where the security service effectively says "whoever brings this token is a fine person; they are ok to get in". It's like having a really close buddy relationship with the boss of the nightclub when you are having troubles with the monsters guarding the door. I'm getting a bit ahead of myself here, though.

In the post about claims I claimed that "I am authorized to approve corporate acquisitions with a transaction volume of up to $5Bln". That's a pretty obvious lie. If there was such a thing as a one-click shopping button for companies on some Microsoft Intranet site (there isn't, don't get any ideas) and I were to push it, I surely should not be authorized to execute the transaction. The imaginary "just one click and you own Xigg" button would surely have some sort of authorization mechanism on it.

I don't know what Xigg is assumed to be worth these days, but there is actually be a second authorization gate to check. I might indeed be authorized to do one-click shopping for corporate acquisitions, but even with my made-up $5Bln limit claim, Xigg may just be worth more that I'm claiming I'm authorized to approve. I digress.

How would the one-click-merger-approval service be secured? It would expect some sort of token that absolutely, positively asserts that my claim "I am authorized to approve corporate acquisitions with a transaction volume of up to $5Bln" is truthful and the one-click-merger-approval service would have to absolutely trust the security service that is making that assertion. The resulting token that I'm getting from the security service would contain the claim as an attribute of the assertion and that assertion would be signed and encrypted in mysterious (for me) yet very secure and interoperable ways, so that I can't tamper with it as much as I look at the token while having it in hands.

The service receiving the token is the only one able to crack the token (I'll get to that point in a later post) and look at its internals and the asserted attributes. So what if I were indeed authorized to spend a bit of Microsoft's reserves and I were trying to acquire Xigg at the touch of a button and, for some reason I wouldn't understand, the valuation were outside my acquisition limit? That's the service's job. It'd look at my claim, understand that I can't spend more than $5Bln and say "nope!" - and it would likely send email to SteveB under the covers. Trouble.

Bottom line: For a client application, a token is a collection of opaque (and mysterious) security stuff. The token may contain an assertion (saying "yep, that's actually true") about a claim or a set of claims that I am making. I shouldn't have to care about the further details unless I'm writing a service and I'm interested in some deeper inspection of the claims that have been asserted. I will get to that.

Before that, I notice that I talked quite a bit about some sort of "security service" here. Next post...

Categories: Architecture | SOA | CardSpace | WCF | Web Services

April 2, 2008
@ 08:20 PM

If you ask any search engine "What is a Claim?" and you mean the sort of claim used in the WS-* security space, you'll likely find an answer somewhere, but that answer is just as likely buried in a sea of complex terminology that is only really comprehensible if you have already wrapped your head around the details of the WS-* security model. I would have thought that by now there would be a simple and not too technical explanation of the concept that's easy to find on the Web, but I haven't really had success finding one. 

So "What is a Claim?" It's really simple.

A claim is just a simple statement like "I am Clemens Vasters", or "I am over 21 years of age", or "I am a Microsoft employee", or "I work in the Connected Systems Division", or "I am authorized to approve corporate acquisitions with a transaction volume of up to $5Bln". A claim set is just a bundle of such claims.

When I walk up to a service with some client program and want to do something on the service that requires authorization, the client program sends a claim set along with the request. For the client to know what claims to send along, the service lets it know about its requirements in its policy.

When a request comes in, this imaginary (U.S.) service looks at the request knowing "I'm a service for an online game  promoting alcoholic beverages!". It then it looks at the claim set, finds the "I am over 21 years of age" claim and thinks "Alright, I think we got that covered".

The service didn't really care who was trying to get at the service. And it shouldn't. To cover the liquor company's legal behind, they only need to know that you are over 21. They don't really need to know (and you probably don't want them to know) who is talking to them. From the client's perspective that's a good thing, because the client is now in a position to refuse giving out (m)any clues about the user's identity and only provide the exact data needed to pass the authorization gate. Mind that the claim isn't the date of birth for that exact reason. The claim just says "over 21".

Providing control over what claims are being sent to a service (I'm lumping websites, SOAP, and REST services all in the same bucket here) is one of the key reasons why Windows CardSpace exists, by the way. The service asks for a set of claims, you get to see what is being asked for, and it's ultimately your personal, interactive decision to provide or refuse to provide that information.

The only problem with relying on simple statements (claims) of that sort is that people lie. When you go to the Jack Daniel's website, you are asked to enter your date of birth before you can proceed. In reality, it's any date you like and an 10-year old kid is easily smart enough to figure that out.

All that complex security stuff is mostly there to keep people honest. Next time ...

Categories: Architecture | SOA | CardSpace | WCF | Web Services

I highly recommend reading Vittorio's most excellent and illuminating blog entry for how to use the new features we've added to BizTalk Identity Services for allowing you to use 3rd Party Managed Cards.

Categories: CardSpace | ISB

A flock of pigs has been doing aerobatics high up over Microsoft Campus in Redmond in the past three weeks. Neither City of Redmond nor Microsoft spokespeople returned calls requesting comments in time for this article. An Microsoft worker who requested anonymity and has seen the pigs flying overhead commented that "they are as good as the Blue Angels at Seafair, just funnier" and "they seem to circle over building 42 a lot, but I wouldn't know why".

In related news ...

We wrapped up the BizTalk Services "R11" CTP this last Thursday and put the latest SDK release up on http://labs.biztalk.net/. As you may or may not know, "BizTalk Services" is the codename for Microsoft's cloud-based Identity and Connectivity services - with a significant set of further services in the pipeline. The R11 release is a major milestone for the data center side of BizTalk Services, but we've also added several new client-facing features, especially on the Identity services. You can now authenticate using a certificate in addition to username and CardSpace authentication, we have enabled support for 3rd party managed CardSpace cards, and there is extended support for claims based authorization.

Now the surprising bit:

Only about an hour before we locked down the SDK on Thursday, we checked a sample into the samples tree that has a rather unusual set of prerequisites for something coming out of Microsoft:

Runtime: Java EE 5 on Sun Glassfish v2 + Sun WSIT/Metro (JAX-WS extensions), Tool: Netbeans 6.0 IDE.

The sample shows how to use the BizTalk Services Identity Security Token Service (STS) to secure the communication between a Java client and a Java service providing federated authentication and claims-based authorization.

The sample, which you can find in ./Samples/OtherPlatforms/StandaloneAccessControl/JavaEE5 once you installed the SDK, is a pure Java sample not requiring any of our bits on either the service or client side. The interaction with our services is purely happening on the wire.

If you are a "Javahead", it might seem odd that we're shipping this sample inside a Windows-only MSI installer and I will agree that that's odd. It's simply a function of timing and the point in time when we knew that we could get it done (some more on that below). For the next BizTalk Services SDK release I expect there to be an additional .jar file for the Java samples.

It's important to note that this isn't just a thing we did as a one-time thing and because we could. We have done a significant amount of work on the backend protocol implementations to start opening up a very broad set of scenarios on the BizTalk Services Connectivity services for platforms other than .NET. We already have a set of additional Java EE samples lined up for when we enable that functionality on the backend. However, since getting security and identity working is a prerequisite for making all other services work, that's where we started. There'll be more and there'll be more platform and language choice than Java down the road.

Just to be perfectly clear: Around here we strongly believe that .NET and the Windows Communication Foundation in particular is the most advanced platform to build services, irrespective of whether they are of the WS-* or REST variety. If you care about my personal opinion, I'll say that several months of research into the capabilities of other platforms has only reaffirmed that belief for me and I don't even need to put a Microsoft hat on to say that.

But we recognize and respect that there are a great variety of individual reasons why people might not be using .NET and WCF. The obvious one is "platform". If you run on Linux or Unix and/or if your deployment target is a Java Application Server, then your platform is very likely not .NET. It's something else. If that's your world, we still think that our services are something that's useful for your applications and we want to show you why. And it is absolutely not enough for us to say "here is the wire protocol documentation; go party!". Only Code is Truth.

I'm also writing "Only Code is Truth" also because we've found - perhaps not too surprisingly - that there is a significant difference between reading and implementing the WS-* specs and having things actually work. And here I get to the point where a round of public "Thank You" is due:

The Metro team over at Sun Microsystems has made a very significant contribution to making this all work. Before we started making changes to accommodate Java, there would have been very little hope for anyone to get this seemingly simple scenario to work. We had to make quite a few changes even though our service did follow the specs.

While we were adjusting our backend STS accordingly, the Sun Metro team worked on a set of issues that we identified on their end (with fantastic turnaround times) and worked those into their public nightly builds. The Sun team also 'promoted' a nightly build of Metro 1.2 to a semi-permanent download location (the first 1.2 build that got that treatment), because it is the build tested to successfully interop with our SDK release, even though that build is known to have some regressions for some of their other test scenarios. As they work towards wrapping up their 1.2 release and fix those other bugs, we’ll continue to test and talk to help that the interop scenarios keep working.

As a result of this collaboration, Metro 1.2 is going to be a better and more interoperable release for the Sun's customers and the greater Java community and BizTalk Services as well as our future identity products will be better and more interoperable, too. Win-Win. Thank you, Sun.

As a goodie, I put some code into the Java sample that might be useful even if you don't even care about our services. Since configuring the Java certificate stores for standalone applications can be really painful, I added some simple code that's using a week-old feature of the latest Metro 1.2 bits that allows configuring the Truststores/Keystores dynamically and pull the stores from the client's .jar at runtime. The code also has an authorization utility class that shows how to get and evaluate claims on the service side by pulling the SAML token out of the context and pulling the correct attributes from the token.

Have fun.

[By the way, this is not an April Fool's joke, in case you were wondering]

Categories: Architecture | IT Strategy | Technology | CardSpace | ISB | WCF

August 28, 2007
@ 12:58 AM
Categories: Technology | CardSpace

May 7, 2007
@ 11:00 PM

Steve Maine explains what's in the newest revision of the BizTalk Services SDK, including quite a few (standalone-) surprises for WCF and WF developers. In case you haven't noticed, we've dropped a new and substantially expanded build of the SDK just a week after we published the first SDK.

Stop. Don't leave yet. Before you say "What do I care about BizTalk?", you should know that while BizTalk has been more or less associated with the BizTalk Server 200x product line in the past few years, (Codename-) BizTalk Services is a complementary set of functionality that's not only interesting to BizTalk Server customers, but really to all .NET developers.

Weird? Flip flopping? Confusing? No. The fact that BizTalk is not only BizTalk Server isn't really new. When BizTalk came out back in 2000 and I was very closely looking at what's going on (get it used for $2), the definition read like this in the press release:

The BizTalk Initiative represents the collective set of investments that Microsoft is making to facilitate business process integration within and between organizations using Internet-standard protocols and formats. It includes the BizTalk Framework, the BizTalk.org community and business document library, as well as BizTalk Server 2000, a business process orchestration server and tools for developing, executing and managing distributed business processes. These investments are being made in conjunction with industry standards groups, technology and service providers, as well as key global organizations.

While the envisioned schema exchange BizTalk.org fell flat since industry-wide message-level-schema standardization for "everything" more or less didn't happen in the way people initially expected, what came out of this initiative as a significant element was that the set of specifications then known as the BizTalk Framework 2.0 that acted as a foundation for quite a few of the WS-* specifications and the BizTalk Server product which evolved into a very successful and leading SOA/BPM suite that's soon seeing its next release, BizTalk Server 2006 R2. Fast forward, read Steven Martin's blog entry where he writes:

[...] We see BizTalk Services as a complement to "traditional" BizTalk Server uses on premise. As you need to coordinate SOA on a broader scale beyond the organization, we see the introduction of hosted services as one way to help support federation of business process, messaging, and identity across boundaries. Over time, we want to ensure that BizTalk Server customers will be able to easily use the cloud services in conjunction with their premise technology. [...]

So all in all, a very sane way to think about BizTalk is that the software and services we publish under that name are providing functionality for messaging, process management and connectivity that go beyond the capability of the core .NET Framework.

Categories: BizTalk | CardSpace | ISB

I wrote a slightly Twitter-inspired, fun app over the weekend that's using the BizTalk Services Connectivity service and relay. In the spirit of Software+Services I'm going to give you half of it [for now] ;-)   You must have the BizTalk Services SDK installed to run the sample.

The server app, which I'm keeping to myself for the next few days as part of the experiment, is an extension (add-in) to Windows Live Messenger. The Messenger add-in monitors all chats with tweetiebot@hotmail.com and keeps circular buffer with the last 40 incoming messages. Using the client (which is in the attached archive), you can get a list of "Tweets" and add a new one (same as chatting)

[ServiceContract(Name = "TweetieBot", Namespace = http://samples.vasters.com/2007/05/tweetiebot)]
public interface ITweetieBot
{
  [OperationContract]
  IList<Tweet> GetTweets(DateTime? since);
  [OperationContract]
  void Tweet(string nickname, string text);
}

or you can subscribe to new tweets and get them as they arrive

[ServiceContract(Name = "TweetieEvents", Namespace = http://samples.vasters.com/2007/05/tweetiebot)]
public interface ITweetieEvents
{
  [OperationContract(IsOneWay=true)]
  void OnTweet(Tweet tweet);
}

The client application hooks up to the client (that lives right on my desktop machine) through the BizTalk Services ISB and the server fires events back through the ISB relay into the client as new tweets arrive. So when you run the attached client app, you'll find that it starts with a dump of the current log of the bot and then keeps spitting out events as they arrive.

The client is actually pretty simple. The EventsClient is the subscriber for the pub/sub service (ConnectionMode.RelayMulticast) that writes out the received events to the console. The rest all happens in Main (parsing an validating the command line argument) and in Run.

    class Program
    {
       
class EventsClient :
ITweetieEvents
        {
           
public void OnTweet(Tweet
tweet)
            {
               
Console.WriteLine("[{0}] {1}:{2}"
, tweet.Time, tweet.User, tweet.Text);
            }
        }

       
static void Main(string
[] args)
        {
           
string usageMessage = "Usage: IMBotClient <messenger-email-address>"
;
           
if
(args.Length == 0)
            {
               
Console
.WriteLine(usageMessage);
            }
           
else
            {
               
if (!Regex.IsMatch(args[0], @"^([\w\-\.]+)@((\[([0-9]{1,3}\.){3}[0-9]{1,3}\])|(([\w\-]+\.)+)([a-zA-Z]{2,4}))$"
))
                {
                   
Console
.WriteLine(usageMessage);
                   
Console.WriteLine("'{0}' is not a valid email address"
);
                }
               
else
                {
                    Run(args[0]);
                }
            }
        }

       
private static void Run(string
emailAddress)
        {
           
EndpointAddress serviceAddress =
               
new EndpointAddress(String.Format(String.Format("sb://{0}/services/tweetiebot/{1}/service"
                                    
RelayBinding.DefaultRelayHostName, Uri
.EscapeDataString(emailAddress))));
           
EndpointAddress eventsAddress =
               
new EndpointAddress(String.Format(String.Format("sb://{0}/services/tweetiebot/{1}/events",
                                   
RelayBinding.DefaultRelayHostName, Uri
.EscapeDataString(emailAddress))));

The URI scheme for services that hook into the ISB is "sb:" and the default address of the relay is encoded in the SDK assemblies. We set up two endpoints here. One for the client channel to fetch the initial list and one for the event subscriber. 

            RelayBinding relayBinding = new RelayBinding();
     

            
ServiceHost eventsHost = new ServiceHost(typeof(EventsClient
));
           
RelayBinding eventBinding = new RelayBinding(RelayConnectionMode
.RelayedMulticast);
            eventsHost.AddServiceEndpoint(
typeof(ITweetieEvents
), eventBinding, eventsAddress.ToString());
            eventsHost.Open();

           
ChannelFactory<TweetieBotChannel> channelFactory = new ChannelFactory<TweetieBotChannel
>(relayBinding, serviceAddress);
           
TweetieBotChannel
channel = channelFactory.CreateChannel();
            channel.Open();

The two *.Open() calls will each prompt for a CardSpace authentication, so you will have to be registered to run the sample. Once you have opened the channels (and my service is running), you'll be able to pull the list of current tweets. Meanwhile, whenever a new event pops up, the EventsClient above will write out a new line.

            IList<Tweet> tweets = channel.GetTweets(lastTime);
           
foreach (Tweet tweet in
tweets)
            {
               
Console.WriteLine("[{0}] {1}:{2}"
, tweet.Time, tweet.User, tweet.Text);
            }

           
Console.WriteLine("Press ENTER to quit at any time"
);
           
Console
.ReadLine();

            eventsHost.Close();
            channel.Close();
            channelFactory.Close();
        }        


So when you run the app, you can chat (anyone can, you don't need to be a buddy) tweetiebot@hotmail.com through Live Messenger and you'll see your chat lines (and potentially others') popping out as events from the service bus.

To run the sample with my bot, you need to call the client with "IMBotClient tweetiebot@hotmail.com" and select your BizTalk Services Information Card twice as you are prompted.

Privacy notice: I'm anonymizing the name of the contact only insofar as I'm clipping anything including and following the "at" sign of the user that chats the bot. So whatever you say is published as "emailname: text line"

IMBotClient.zip (3.61 KB)
Categories: Technology | BizTalk | CardSpace | ISB

April 2, 2007
@ 07:46 PM

Before I continue pointing out SDK samples, why not take a look at a great end-to-end .NET Framework 3.0 demo first? It's been out there for a while and hence this isn't really news, but in case you've not seen it (or the latest revision of it) go check out DinnerNow. The demo covers WCF, Workflow, CardSpace and PowerShell. Awesome piece of work from our Evangelism team.

Categories: WCF | Workflow | CardSpace