WS-Trust “From each,according to his ability;to each, according to his need. “ Karl marx Ahmet Emre Naza Selçuk Durna 2001100379 2001101675.

WS-Trust

“From each,according to his ability;to each , according to his need. “

Karl marx

Ahmet Emre Naza Selçuk Durna 2001100379 2001101675

DefinitionsClaim – A claim is a statement made about a client, service or other resourceSecurity Token – A security token represents a collection of claims.Security Token Service – A security token service (STS) is a Web service that issues security tokensTrust – Trust is the characteristic that one entity is willing to rely upon a second entity to execute a set of actions and/or to make set of assertions about a set of subjects and/or scopes.Interoperable - able to exchange and use information.

Introduction Interoperable security problem WS-Security will standardize how information is added to

SOAP messages One important class of information is security

tokens(X.509 ,Kerberos ,SAML ,XACML ,etc) Two scenarios:

WS-Security policy specifies how web services actors can assert to potential transaction partners their policies with respect to WS-Security mechanisms, including their capabilitities and preferences with respect to security tokens

WS-Trust is a proposal that enables security token interoperability by defining a request/response protocol by which SOAP actors can request of some trusted authority that a particular security token be exchanged for another.

WS-Trust OverviewA SOAP message protected by WS-Security presents three possible issues with regards to security tokens:

Security token format incompatibility Security token trust Namespace differences

WS-Trust OverviewWS-Trust addresses these issues by:

Defining a request/response protocol Client sends RequestSecurityToken Client receives RequestSecurityTokenResponse

Introducing a Security Token Service (STS)

STS Functions

A Security Token Service allows:

Token Exchange

Token Issuance

Token Validation

WS-Trust Model

Request – Challenge Operation

Client STS

Client requests token from STS

STS sends a challenge to Client

Client sends an answer to STS

STS sends token(s) to Client

Example

WS-Trust Example Client understands

X.509 certificates only

Service understands SAML only

The service does not directly trust the client

The client is not required to anticipate the preference that the service has for SAML Assertions

WS-Trust Example

The Security Assertions Markup Language (SAML) is an XML-based framework for Web services that enables the exchange of authentication and authorization information among business partners.

X.509 is a digital certificate standard, specifying certificate structure. Main fields are ID, subject field, validity dates, public key, and CA signature

SAML and X.509 - Reminder

WS-Trust Example – message 1

SOAP client sends initial request to SOAP service:

<soap:Envelope> <soap:Header><ws:Security>

<ws:BinarySecurityToken id="X509token" ValueType="X.509"> sdfOIDFKLSoidefsdflk …

</ws:BinarySecurityToken> <ds:Signature> <ds:Reference><ds:Ref URI="#PO"/>

</ds:Reference> <ds:SignatureValue>akjsdflaksf

</ds:SignatureValue> <ds:KeyInfo> <ws:BinarySecurityTokenReference URI="#X509token"/>

</ds:KeyInfo> </ds:Signature>

</ws:Security></soap:Header><soap:Body>

<po:PurchaseOrder ID="PO"/></soap:Body></soap:Envelope>









Identity of Client established through XML signature









Identity of Client established through XML signature….

Keyed through X.509 certificate


SOAP gateway recognizes that it must map to SAML, so it contacts the STS

<soap:Envelope><soap:Header>

<ws:Security>


<wstrust:RequestSecurityToken><wstrust:TokenType>SAML</TokenType><wstrust:RequestType>ReqExchange</RequestType><wstrust:OnBehalfOf><ws:BinarySecurityToken id="originaltoken"ValueType="X.509>

sdfOIDFKLSoidefsdflk …</ws:BinarySecurityToken>

</wstrust:OnBehalfOf></wstrust:RequestSecurityToken>

</soap:Body></soap:Envelope>


<ws:Security>






The RequestSecurityToken object is the core of this request…


<ws:Security>






... Which is asking for a SAML token…


<ws:Security>






... Which is asking for a SAML token in exchange for the provided X.509 token.


The STS sends back the token in the requested format

<soap:Body><wstrust:RequestSecurityTokenResponse><wstrust:TokenType>SAML</TokenType><wstrust:RequestedSecurityToken><saml:Assertion AssertionID="2se8e/vaskfsdif="Issuer="www.sts.com"IssueInstant="2002-06-19T16:58:33.173Z"><saml:Conditions NotBefore="2002-06-19T16:53:33.173Z"NotOnOrAfter="2002-06-19T17:08:33.173Z"/>

<saml:AuthenticationStatement AuthenticationMethod= "urn:oasis:names:tc:SAML:1.0:am:X.509"AuthenticationInstant="2002-06-19T16:57:30.000Z"><saml:Subject>

...converted client identifier...</saml:Subject>

</saml:AuthenticationStatement><ds:Signature><-- calculated by STS --></ds:Signature>

</saml:Assertion></wstrust:RequestedSecurityToken>

</wstrust:RequestSecurityTokenResponse></soap:Body>







The SAML assertion is returned







The new client identifier is used


The gateway formats and send the message for the service

<ws:Security><saml:AssertionAssertionID="2se8e/vaskfsdif=“ Issuer="www.sts.com"IssueInstant="2002-06-19T16:58:33.173Z"><saml:ConditionsNotBefore="2002-06-19T16:53:33.173Z"NotOnOrAfter="2002-06-19T17:08:33.173Z"/><saml:AuthenticationStatement AuthenticationMethod= "urn:oasis:names:tc:SAML:1.0:am:X.509"AuthenticationInstant="2002-06-19T16:57:30.000Z"><saml:Subject><saml:NameIdentifier>Client</saml:NameIdentifier><saml:SubjectConfirmation><saml:ConfirmationMethod>

urn:oasis:names:tc:SAML:1.0:cm:sender-vouches</saml:ConfirmationMethod>

</saml:SubjectConfirmation></saml:Subject>


</saml:Assertion></ws:Security>






The SAML Assertion is inserted






The ConfirmationMethod is sender-vouches

Conclusion WS-trust address the security token

needs of SOAP messages secured using WS-security. Format: A STS is used to exchange tokens

into formats understandable by recipients Trust: The STS issues signed tokens

forming the basis of trust for entities with which it has formed a trust relationship.

Namespace: The STS will return tokens in appropriate syntax for the recipient.

Credits WS-trust spec: http://www-106.ibm.com/developerworks/library/ws-trust/ XML.com WS-trust overviewhttp://webservices.xml.com/lpt/a/ws/2003/06/24/ws-trust.html

WS-Trust “From each,according to his ability;to each, according to his need. “ Karl marx Ahmet Emre Naza Selçuk Durna 2001100379 2001101675.

Documents

particular security

security tokenswstrust

security tokenstrust

security tokensx

wssecurity policy

wssecurity presents

wssecurity mechanisms

soap service