This took some time and you are lucky if you hit this after a search. This extension method allows you to decrypt a SAML 1.1 security token using Geneva Framework.

public static ClaimsIdentityCollection ToClaimsIdentityCollection(this GenericXmlSecurityToken token, string thumbprintPrivateKey, string thumbprintIssuerPublicKey, TrustVersion trustVersion)
{
    // Decrypt token
    var tokenString = new StringReader(token.TokenXml.OuterXml);
    var reader = XmlReader.Create(tokenString);

    // Resolver
    X509Certificate2 privateKey = CertificateUtility.GetCertificateByThumbprint(StoreName.My, StoreLocation.LocalMachine, thumbprintPrivateKey);
    X509SecurityToken privateKeyToken = new X509SecurityToken(privateKey);
    X509Certificate2 issuerKey = CertificateUtility.GetCertificateByThumbprint(StoreName.TrustedPeople, StoreLocation.LocalMachine, thumbprintIssuerPublicKey);
    X509SecurityToken issuerKeyToken = new X509SecurityToken(issuerKey);
    List<SecurityToken> tokens = new List<SecurityToken>();
    tokens.Add(privateKeyToken);
    tokens.Add(issuerKeyToken);
    SecurityTokenResolver outOfBandTokenResolver = SecurityTokenResolver.CreateDefaultSecurityTokenResolver(new ReadOnlyCollection<SecurityToken>(tokens), false);

    var samlHandler = SecurityTokenHandlerCollection.DefaultHandlers.SingleOrDefault(handler => handler is Saml11SecurityTokenHandler) as Saml11SecurityTokenHandler;
    samlHandler.SamlSecurityTokenRequirement.IssuerTokenResolver = outOfBandTokenResolver;
    EncryptedSecurityTokenHandler h = new EncryptedSecurityTokenHandler(outOfBandTokenResolver, new SecurityTokenHandlerCollection(new SecurityTokenHandler[] { samlHandler }));
    var serializer2 = new SecurityTokenSerializerAdapter(
        new SecurityTokenHandlerCollection(new SecurityTokenHandler[] { h }),
        SecurityVersion.WSSecurity11,
        trustVersion,
        trustVersion == TrustVersion.WSTrust13 ? SecureConversationVersion.WSSecureConversation13 : SecureConversationVersion.WSSecureConversationFeb2005,
        false,
        null,
        null,
        null);
    var samlSecurityToken = serializer2.ReadToken(reader, outOfBandTokenResolver);

    samlHandler.SamlSecurityTokenRequirement.IssuerNameRegistry = new NullIssuerNameRegistry();

    var handlers = new SecurityTokenHandlerCollection(new SecurityTokenHandler[] { samlHandler });
    var claims = handlers.ValidateToken(samlSecurityToken);

    return claims;
}

The way to use it:

var token = GetTokenFromSomewhere();
token.ToClaimsIdentityCollection( "thmbprint of the cert used to decrypt the token",
                                  "thmbprint of the cert used to check the signature of the issuer",
                                  TrustVersion.WSTrust13 or TrustVersion.WSTrustFeb2005 );

Download it from here

Microsoft Argentina organized the local-mini version of PDC. I will be there showing Windows Azure with Edgardo.

The talk will be mainly demos (as usual and explain some concepts around Windows Azure.

You can register here (it seems it’s all booked though): http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032394696&Culture=es-AR

Other southies will be presenting as well at this event:

• Martin Salias will be talking about the future of the languages (F# and C#)
• Paulo Arancibia and Julian Dominguez will be showing how to develop data driven apps using the new DataGrid and Ribbon controls of WPF.

See you there…

In the previous post I introduced a scenario where you can use .NET Services Access Control and Windows LiveID to delegate authentication and authorization. In this post we will go through the different pieces needed in the application to perform authorization checks. First thing will be configure the passive federation using Geneva on the application and later we will create an ASP.NET MVC action filter to perform the access check against the incoming claims.

Note: all the code showed here is using Microsoft Identity Framework "Zermatt" Beta 1. The new Geneva Framework might have some changes.

Configuring passive federation on the website

Configure passive federation on the website is about defining which SAML token version we will accept and the certificate we will use to decrypt the incoming token. The following configuration uses Zermatt Beta 1, so this probably changes on Geneva.

<microsoft.identityModel>
    <tokenHandlers>
      <remove type="Microsoft.IdentityModel.Tokens.Saml11.Saml11TokenHandler, Microsoft.IdentityModel, Version=0.4.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
      <add type="Microsoft.IdentityModel.Tokens.Saml11.Saml11TokenHandler, Microsoft.IdentityModel, Version=0.4.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
        <samlSecurityTokenRequirement>
          <allowedAudienceUris>
            <add value="http://localhost/YourApp/" />
          </allowedAudienceUris>
        </samlSecurityTokenRequirement>
      </add>
    </tokenHandlers>
    <federatedAuthentication enabled="true">
    </federatedAuthentication>
    <serviceCertificate>
      <certificateReference findValue="01 20 …" storeLocation="LocalMachine" storeName="My" x509FindType="FindByThumbprint" />
    </serviceCertificate>
  </microsoft.identityModel>

When the user click on the sign in button, the link will point to to the .NET Services Access Control passive STS url. The following method uses Geneva to generate this WS-Federation url.

private static string GetFederationUrl(string realm, string issuer, string homeRealm, string returnUrl)
{
    FederatedAuthenticationModule fam = new FederatedAuthenticationModule();
    fam.Realm = realm;
    fam.Issuer = issuer;
    fam.Reply = returnUrl;
    SignInRequestMessage signInMsg = fam.CreateSignInRequest();
    signInMsg.Parameters.Add("whr", homeRealm);
    string url = signInMsg.WriteQueryString();
    return url;
}

The following code and configuration will give you an idea of the url that is being built. Pay attention to this url because a small change might break the whole thing.

string url = GetFederationUrl(ConfigurationManager.AppSettings["AccessControlRealm"],
                            ConfigurationManager.AppSettings["AccessControlIssuer"],
                            ConfigurationManager.AppSettings["AccessControlHomeRealm"],
                            replyTo);

<!– Windows Azure Federation –>
<add key="AccessControlRealm" value="http://localhost/YourApp/"/> <!– should match to a scope –>
<add key="AccessControlIssuer" value="https://accesscontrol.windows.net/passivests/yoursolution/LiveFederation.aspx"/>
<add key="AccessControlDefaultReply" value="http://localhost/YourApp" />
<add key="AccessControlHomeRealm" value="http://login.live.com" />

The AccessControlRealm config is important because it will match the scope on your solution. You will have to configure the scope to encrypt with the public key of your website certificate and create the claim mappings from Windows LiveID to your well known claims. If you don’t have the scope created or configured to output at least one claim you will get a 403 Forbidden on the .NET Services Access Control STS.

Performing access check in the web site

Now that we have everything configured and the token should be coming back to our website, it’s time to do the access check. By using Geneva, the token will be transformed to a Principal object and it will be accessed through the ClaimsPrincipal static class. On the other hand, ASP.NET MVC allow us to plug into the action execution pipeline and get access to the context data like route values. The following code shows an ActionFilterAttribute that will grab the claims from the the Geneva ClaimsPrincipal and will call a strategy class that will perform the access check. If the access check is not successful, the filter will render a NotAuthorized view.

namespace YourApp.Identity
{
    using System;
    …

    public class ClaimAuthorizationRouteFilterAttribute : ActionFilterAttribute
    {
        public ClaimAuthorizationRouteFilterAttribute(string[] operations)
        {
            this.Operations = operations;
        }

        public string[] Operations { get; set; }

        public override void OnActionExecuting(ActionExecutingContext context)
        {
            var identity = ClaimsPrincipal.Current.Identity as IClaimsIdentity;
            var claims = identity.Claims.ToArray();
            var routeData = context.RouteData.Values.ToArray();
            var strategy = CreateAuthorizationStrategy();
            var executionContext = new ExecutionContext()
            {
                ClaimsNeeded = Operations,
                OperationContextData = routeData,
            };

            if (!strategy.IsAuthorizedFor(executionContext, claims))
            {
                context.Result = new ViewResult
                {
                    ViewName = "NotAuthorized"
                };
            }

            base.OnActionExecuting(context);
        }

    }
}

Finally, the following code shows an implemented strategy for a multi tenant application that manage projects.

namespace YourApp.Identity
{
    using System.Linq;
    using System;

    public class StandardAuthorizationStrategy : IAuthorizationStrategy
    {
        private const string ProjectClaimType = "urn:Project";
        private const string TenantClaimType = "urn:Tenant";
        private const string OperationClaimType = "urn:Operation";

        public bool IsAuthorizedFor(ExecutionContext context, Microsoft.IdentityModel.Claims.Claim[] claims)
        {
            bool authorized = true;
            var tenantClaim = claims.SingleOrDefault(c => c.ClaimType == TenantClaimType);
            var operationClaims = claims.Where(c => c.ClaimType == OperationClaimType);
            var projectClaims = claims.Where(c => c.ClaimType == ProjectClaimType);
        var tenant = context.OperationContextData["Tenant"].ToString();
        var project = context.OperationContextData["Project"].ToString();

            if (!string.IsNullOrEmpty(tenant))
            {
                authorized &= tenantClaim.Value.Equals("*", StringComparison.OrdinalIgnoreCase) ||
                              tenantClaim.Value.Equals(tenant, StringComparison.OrdinalIgnoreCase);
            }

            if (!string.IsNullOrEmpty(project))
            {
                authorized &= projectClaims.Where( p => p.Value.Equals("*", StringComparison.OrdinalIgnoreCase)).Count() > 0 ||
                              projectClaims.Where( p => p.Value.Equals(project, StringComparison.OrdinalIgnoreCase)).Count() > 0;
            }

            if (context.Operations != null)
            {
                bool temp = true;
                foreach (string op in context.ClaimsNeeded)
                {
                    temp &= operationClaims.Where(o => o.Value.Equals(op, StringComparison.OrdinalIgnoreCase)).Count() > 0 ||
                            operationClaims.Where(o => o.Value.Equals("*", StringComparison.OrdinalIgnoreCase)).Count() > 0;
                }
                authorized &= temp;
            }

            return authorized;
        }
    }
}

The only thing left is to put an attribute above the action. The following attribute specifies that the New action will be executed if the incoming token contains the following "urn:Operation" claims.

public class ProjectsController : Controller
{

        [ClaimAuthorizationRouteFilter(new string[] {
                                            "AddUser",
                                            "AddUsersToProject",
                                            "CreateProject" })]
        public ActionResult New() {
        ….

    }

    …

}

So if a user browses to: http://yourapp/Contoso/Projecsts/New, the filter will call the strategy that will check:

• if the user contains a tenant claim with the value "Contoso" (taken from the route data)
• if the user contains three operation claims: AddUser, AddUsersToProject and CreateProject

And if a user browses to: http://yourapp/Contoso/Projecsts/some-project/Edit, the filter will call the strategy that will check:

• if the user contains a "tenant" claim with the value "Contoso" (taken from the route data)
• if the user contains the "operation" claims specified in the Edit action
• if the user contains a "project" claim with the value "some-project"

The last couple of months together with other people at Southworks we’ve been working with the DPE team on samples, demos, hands on labs for PDC all related to the cloud computing services Microsoft announced at PDC, the Azure Services Platform. 

During the week, I attended Kim Cameron’s and Vittorio Bertocci session where they talked about identity federation and claim based architecture using "Geneva" Server, Microsoft Federation Gateway, "Geneva" Framework (previously known as Zermatt) and the .NET Services Access Control. I enjoyed watching Vittorio during the session. 

Other interesting things we did in the identity arena with Ryan Dunn is use the .NET Services Access Control and Windows Live ID to delegate authentication and authorization to the cloud. In this post I will introduce the scenario where you can federate your application against .NET Services Access Control which indeed federates against Windows LiveID. This will allow users of your application to log in to your application using their Windows LiveID account and then use .NET Services Access Control to transform the email claim to a set of claims to perform authorization access checks.

Identity + Access Control using Windows Live ID + .NET Services Access Control

Windows Live ID can authenticate users of your web site and then use .NET Services Access Control to map claims between the Live ID (email) and some other claim (like role, operation, task). The image below shows a claim mapping that you would create in your .NET Services account.

The output claims could be used later in the application to perform access check against resources or modify the UI according to the incoming claims. The flow is governed by the WS-Federation protocol as shown below:

In a nutshell, the browser will click on the Sign In link on the website and it will be redirected to the token issuer, in this case the .NET Services Access Control passive STS. The home realm on the url will be login.live.com and the .NET Services STS trust on Windows LiveID tokens. The user will log in on Windows LiveID and it will send the token back to the .NET Services STS. Finally the claim mapping will occur and the token will come back to the website with the authorization claims.

In the following post I will show how to configure your application to read the incoming token claims and do access check over page urls.

The work we did through the last couple of months is materialized now. James Conard and the DPE team (Nigel Watling, Ryan Dunn, Vittorio Bertocci, Drew Robbins, et al) were able to hit the road before anyone else at Microsoft by releasing the Azure Services Training Kit.

I was walking through the Hands On Labs lounge today, watching at people doing lines to do the labs.

The kit includes labs on:

• SQL Data Services
• Windows Azure
• .NET Services Service Bus
• .NET Services Access Control
• .NET Services Workflow

You will need an invitation code, but you will be able to read the document and code to get lots of information.

Download it now

In the other presentation I will join Federico Boerr and together we will try to demystified performance and load testing based on real world experience.

Since the audience will be half students and half professional developers, we decided to do both presentations in a extremely pragmatic fashion, showing tips & tricks. The deck of one of the presentations has just 3 slides! I will post them after the event, but here you have a preview:

Presentation (3 - 4 PM): 14 rules for web app performance improvement	Presentation (4:15 - 5:15 PM): How To: Perf and Load Testing

On the other hand, Southworks is one of the sponsors of the event and several other southies will be presenting as well (actually 7 presentations, wow!):

• Johnny and Lito about the Microsoft Data platform with SQL (they will do the demo that Southworks prepared for BillG KeyNote at TechEd Orlando 2008)
• Beto y Ezequiel Jadib will do a dev + IT talk on application health monitoring
• Martin Salias on his usual and great dynamic languages talk (Python on .NET)
• Angel Lopez is covering one of the speakers and will do one of our favorites topics: MS Robotics Studio
• Augusto Alvarez on IIS7

Southworks will have a booth as well, so feel free to stop by for some geek talks!

My interest in Software as a Service (SaaS) born during a trip to Microsoft in 2006. Looking for an interesting topic to elaborate on my graduate thesis, I started digging on different areas and asking different colleagues and friends. Initially, influenced by the work of Arvindra Sehmi, I got interested in agent programming (BDI agents, multi-agents systems, etc). Later, Eugenio Pace, a mentor and friend, commented me about an emerging model of software distribution. After a couple of months, Alejandro Jack (mentor and friend also), contacted me with John DeVadoos (former director of the Architecture Strategy Team at Microsoft, now leading the patterns & practices team). This group was formed by Gianpaolo Carraro and Fred Chong initially and last year Eugenio joined them and Fred left. Their daily job consists of researching the Software as a Service model from the architectural point of view. As part of this challenge, the group establishes relationships with clients interested in the model and with product teams looking for feedback to shorten the gap on the platform. The group also publishes a number of papers and proof of concepts using Microsoft technologies. I did a good connection with them and finally decided to pick Software as a Service as the topic for my thesis.

Throughout the last two years I’ve been collaborating with this group writing proof of concepts, preparing and delivering workshops. On the right, it’s me working with Eugenio (on the left) at building 20 one year ago (Gianpaolo is taking the picture). The post-its on the wall are the user stories for Northwind Hosting (I was happy to see Google App Engine six months later as a validation of our thinking).

I’ve witnessed the growth of Software as a Service since it was in the initial stages up to now that has started being adopted by the industry and lately has been extended to a broader term: Cloud Computing.

The thesis is the sum of all the experience I gather along these years and it’s an attempt to summarize and compress the taxonomy of Software as a Service applications on a single model; that is more about “breadth” than “depth”. This model was based on Feature Modeling, a technique used in Software Product Lines (SPL). Feature Modeling is a method and notation to elicit and represent common and variable features of the system in a system family. It was first proposed by Kang et al in Feature Oriented Domain Analysis by the Software Engineering Institute (SEI, 90). It’s been used lately in Generative Software Development (Czarnecki, 2005), which aims at modeling and implementing system families in such a way that a given system can be automatically generated from specification written in one or more textual or graphical domain specific languages (DSLs). Since SaaS and Cloud Computing are evolving fast I wanted to separate the problem space from the solution space allowing the individual development and growth of each of them. Feature Modeling helped because it was focused on the capabilities. I didn’t try to use Feature Modeling to automate the generation of this kind of systems, though. The priority was having a model that allow me to frame and explain Software as a Service systems.

Separation between problem and solution space (Overview of Generative Software Development, Czarnecki)

Part of defining the problem space consisted of doing a domain analysis. This is an activity of SPL aiming to characterize a domain by understanding their commonality and variability. If you follow this blog you might have read the cloud computing taxonomy map post. That was an exercise during the domain analysis that helped me understand the different scopes, offerings and features of Software as a Service.

Domain analysis of Software as a Service

With this information, I’ve spent a couple of days pasting post-its on the wall, trying to group the features and capabilities in a way that makes sense. The end result was this “onion” diagram where each category holds the different features of Software as a Service.

The model is later refined, from the taxonomy above to the capability layer (problem space) and finally to the implementation layer (solution space) as shown in the following figure.

The thesis then describes each of the capabilities in a high level fashion and then proposes patterns, architecture styles and technologies to implement those capabilities.

The following feature tree is an instance of the capability layer of the model for the LitwareHr application (grayed capabilities are not part of LitwareHr system). This content is in Spanish, but it will be soon available in English.

The thesis also includes other non technical aspects like

• Adoption and diffusion analysis of SaaS based on market research
• Barriers for adoption
• Historical context (starting from specialization in the 19th century, passing through outsourcing, mainframes and what not
• Roles and ecosystem

I want to thanks again to all the people that helped directly or indirectly: my family and fiancee, Alejandro Jack, Gustavo López, Eugenio Pace, Gianpaolo Carraro, Fred Chong, Arvindra Sehmi, Ariel Schapiro, Angel “Java” Lopez and to all Southworks.

Fell free to download the Spanish version and let me know if you find it useful to matias at southworks dot net.

This first post will be about the simplest scenario in identity management: the Active Client with a single STS. In other words, a client that calls a web service with a policy that says that you need to use a certain token to talk to him.

The sequence of actions in this scenario is:

1. Since the client needs to obtain a token before talk to the service, it will make a WS-Trust call to the STS sending some kind of credentials. It could be Windows credentials, a X509 certificate, username and password or maybe another token (we’ll leave that for a future post).
2. The STS will authenticate the caller and probably will output some claims about him. These claims might come from some repository like a database or AD. If the client is using Windows credentials, maybe the claims will be the groups the user belongs, the email and the full name. If the client is using username and password, the claims could be the roles stored in a database table. However, the claims could be anything you want that will be used later to perform access checks on the service.
3. The response is sent to the client containing an RSTR (Request Security Token Response) that will contain the requested security token with the claims. This token can be encrypted so only the service can decrypt it. For doing that, the STS will use the public key of the service certificate. The token will be also signed by the STS to avoid untrusted issuers. To sign the token, the STS will use a private key.
4. Finally, the client calls the service using the token obtained in 3. The service will only accept tokens of trusted issuers. Since there is a trust relationship between our STS and the service, the latter will have the public key of the STS that will allow him to check the signature of the token.

Having the sequence of things defined, we’ll see how this can be achieved using Zermatt Beta 1. First, let me put some context on some of the decisions I will take.

One of the things I really like about Zermatt is the WSTrustClient class. This simple class allows anyone to issue a RST to an STS. If you ever tried to implement the approach depicted above with WCF you might have met with the wsFederationHttpBinding. This binding encapsulates the sequence above so the client doesn’t have to worry about the behind the scenes of obtaining tokens. While this is good in some cases, when I started playing with this identity architecture, I felt that there was some kind of "black magic" happening. As someone that uses Reflector as its primary tool to solve most of the challenges with emergent technologies, I wanted to know how all this worked and I wanted to have control over the tokens. Well, knowing the theory helps a lot. I also recommend you to use WSTrustClient  and "do it yourself".

[1] Issue token

We will use a simple username and password to call the STS. The following method uses the WSTrustClient class to call the STS in localhost:6001/IPSTS. Notice the usage of WCF WSHttpBinding with Windows credentials. The RequestType property of the RequestSecurityToken class is not the regular WS-Trust issue SOAP action URI(http://schemas.xmlsoap.org/ws/2004/04/security/trust/RST/Issue), but a custom one. This is because Zermatt supports different WS-Trust versions and will do the transformation to the correct URI on runtime depending on the WSTrust version (by default is Feb 2005 version)

static SecurityToken GetToken(string username, string password)
{
    var binding = new WSHttpBinding(SecurityMode.Message);
    binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Windows;
    binding.Security.Message.ClientCredentialType = MessageCredentialType.Windows;

    var ipAddress = new EndpointAddress("http://localhost:6001/IPSTS");

    var client = new WSTrustClient(binding, ipAddress);

    client.ClientCredentials.Windows.ClientCredential.UserName = username;
    client.ClientCredentials.Windows.ClientCredential.Password = password;

    var rst = new RequestSecurityToken();
    rst.RequestType = "http://schemas.microsoft.com/idfx/requesttype/issue";
    var token = client.Issue(rst);
    return token;
}

[2] Authenticate & fill tokens with claims

The STS in Zermatt have two methods to override. The first is GetScope which provides information related to the "scope" where this STS will be used (things like certificates to use to encrypt, to sign, etc) The second is GetOutputSubjects that will provide information about the subject (like claims). Here we are creating one claim of type http://schemas.xmlsoap.org/claim/Group for each group the user belongs.

public override ClaimsIdentityCollection GetOutputSubjects(Scope scope, IClaimsPrincipal principal, RequestSecurityToken request)
{
    var claimsIdentities = new ClaimsIdentityCollection();
    var wI = (WindowsIdentity)principal.Identity;
    var identity = new ClaimsIdentity(principal.Identity);

    foreach (IdentityReference iD in wI.Groups)
    {
        var groupName = new SecurityIdentifier(iD.Value).Translate(typeof(NTAccount)).ToString();
        identity.Claims.Add(new Claim(Constants.GroupClaimType, groupName));
    }
    claimsIdentities.Add(identity);

    return claimsIdentities;
}

[3] Encrypting and signing the RSTR

In the GetScope method we are indicating how we are going to encrypt and sign the token

protected override Scope GetScope(IClaimsPrincipal principal, RequestSecurityToken request)
{
    Scope scope = new Scope(request, SecurityTokenServiceConfiguration.SigningCredentials);

    scope.EncryptingCredentials = new X509EncryptingCredentials(
                                      CertificateUtil.GetCertificateByThumbprint(StoreName.TrustedPeople,
                                                                      StoreLocation.LocalMachine,
                                                                      Constants.EncryptingCertificateThumbprint));
    return scope;
}

[4] Call the service using the token

At this point the client have a token in his hands. Now we need to use it on the outgoing message (on the WS-Security header). Here, we use the WSTrustClientCredentials class and set the SecurityToken we obtained before.

private static void CallService(SecurityToken token)
{
    var client = new ShippingManagerClient();

    var credentials = new WSTrustClientCredentials();
    credentials.IssuedSecurityToken = token;
    client.Endpoint.Behaviors.Remove<ClientCredentials>();
    client.Endpoint.Behaviors.Add(credentials);
    credentials.ConfigureChannel(client.InnerChannel);

    client.NewShipment();
    client.Close();
}

The client will use a custom binding (not the wsFederationHttpBinding). Notice the issuer address is http://notused. We can do this because we are using WSTrustClientCredentials that creates a custom WCF IssuedSecurityTokenProvider. This provider will shortcircuit the interaction with the issuer and will simply return the token we set in the IssuedSecurityToken on WSTrustClientCredentials.

<bindings>
    <customBinding>
        <binding name="CustomBinding_IShippingManager">
            <security defaultAlgorithmSuite="Default" authenticationMode="IssuedTokenForCertificate"
                requireDerivedKeys="true" securityHeaderLayout="Strict" includeTimestamp="true"
                keyEntropyMode="CombinedEntropy" messageProtectionOrder="SignBeforeEncryptAndEncryptSignature"
                messageSecurityVersion="WSSecurity11WSTrustFebruary2005WSSecureConversationFebruary2005WSSecurityPolicy11BasicSecurityProfile10"
                requireSignatureConfirmation="true">
                <issuedTokenParameters keyType="SymmetricKey" tokenType="http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.1#SAMLV1.1">
                    <issuer address="http://notused" binding="wsHttpBinding" />
                    <issuerMetadata address="http://notused/mex" />
                </issuedTokenParameters>
                <localClientSettings cacheCookies="true" detectReplays="true"
                    replayCacheSize="900000" maxClockSkew="00:05:00" maxCookieCachingTime="Infinite"
                    replayWindow="00:05:00" sessionKeyRenewalInterval="10:00:00"
                    sessionKeyRolloverInterval="00:05:00" reconnectTransportOnFailure="true"
                    timestampValidityDuration="00:05:00" cookieRenewalThresholdPercentage="60" />
                <localServiceSettings detectReplays="true" issuedCookieLifetime="10:00:00"
                    maxStatefulNegotiations="128" replayCacheSize="900000" maxClockSkew="00:05:00"
                    negotiationTimeout="00:01:00" replayWindow="00:05:00" inactivityTimeout="00:02:00"
                    sessionKeyRenewalInterval="15:00:00" sessionKeyRolloverInterval="00:05:00"
                    reconnectTransportOnFailure="true" maxPendingSessions="128"
                    maxCachedCookies="1000" timestampValidityDuration="00:05:00" />
                <secureConversationBootstrap />
            </security>
            <textMessageEncoding maxReadPoolSize="64" maxWritePoolSize="16"
                messageVersion="Default" writeEncoding="utf-8">
                <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="65536"
                    maxBytesPerRead="4096" maxNameTableCharCount="16384" />
            </textMessageEncoding>
            <httpTransport manualAddressing="false" maxBufferPoolSize="524288"
                maxReceivedMessageSize="65536" allowCookies="false" authenticationScheme="Anonymous"
                bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
                keepAliveEnabled="true" maxBufferSize="65536" proxyAuthenticationScheme="Anonymous"
                realm="" transferMode="Buffered" unsafeConnectionNtlmAuthentication="false"
                useDefaultWebProxy="true" />
        </binding>
    </customBinding>
</bindings>

On the service side we want to check that the token was issued by someone we trust. To do that, Zermatt provides something called SamlSecurityTokenRequirements (this code is somewhere in the host).           

var handler = collection[typeof(SamlSecurityToken)] as Saml11TokenHandler;
handler.SamlSecurityTokenRequirement.IssuerTokenAuthenticators.Clear();
handler.SamlSecurityTokenRequirement.IssuerTokenAuthenticators.Add(
   new X509SecurityTokenAuthenticator(
      new TokenIssuerCertificateValidator(Constants.IssuerCertificateThumbprint)));   

The TokenIssuerCertificateValidator derives from X509CertificateValidator which has a virtual method ValidateToken. The input parameter of this method is the certificate used to sign the token. The following code will check the thumbprint of the incoming token is the one we expect.

public override void Validate( X509Certificate2 incoming )
{
    if ( incoming.Thumbprint != issuerCertificate.Thumbprint )
    {
        throw new SecurityTokenException( "Issuer certificate validation failed" );
    }
}

Since the service has the private key that allows decrypting the token, we can read the claims. Zermatt will populate the ClaimsPrincipal object that will be accessible from any place in the service pipeline. The WCF ServiceAuthorizationManager might be the place where you want to do check access using the ClaimsPrincipal.

var identity = ClaimsPrincipal.Current.Identity as IClaimsIdentity;
identity.Claims…

Sebastian who has been working with Zermatt for a couple of weeks already, is posting a useful “straight to the point” how to implement active and passive STS’s using Zermatt. The abstractions in Zermatt are making this a joy. I like the separation of the STS from the underlying host (i.e. ASP.NET, WCF, “put-the-name-of-the-next-foundation”) because allows you to reuse the same STS for both the service layer and the presentation layer and have a consistent access control mechanism on both layers using claims.

Also, while we are on the subject, I recommend you to read the latest Architecture Journal on Identity. I just read Vittorio’s article and it has all the things you need to know about the underlying concepts.

I’ve got good feedback on the taxonomy map from the blogsphere (including Jeff Kaplan, from THINK IT Services). I updated the map some time ago but didn’t have time to publish. So here it is rather sooner than later. (I need Pablo’s help to do the animated GIF, so this time is static)