650'412 Java Security

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650.412 Java Security
Week 13
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Tonights Agenda

• Standards Overview
• WSDL
• XML Encryption
• SAML
• XACML
• WS Security
• XKMS
• JWSDP

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Web Services Standards
4
Too much of a good thing?
http//roadmap.cbdiforum.com/reports/protocols/sum
mary.php
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Web Services Security Standards








Source http//www.nwfusion.com/buzz/2002/websec.h
tmlchart
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Web Services Description Language
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WSDL

• A way of describing a Web Service
• Expressed in XML (of course)
• WSDL Core Language 2.0 W3C Working Draft, Aug.
  2004
• Analogous to Java Reflection API
• Allows dynamic discovery
• For a given web service
• What methods are available?
• For each method --
• Arguments and their types
• Return type

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WSDL (Cont.)

• WSDL doesn't convey
• What the methods "do"
• Proper sequencing of calls
• See W3C choreography working group
• WSDL not a security standard per se
• However, WSDL describes legal calls
• Shows how to call a service "safely"
• This forms part of the WS integrity story
• However, WSDL documents not normally signed
• But neither are Schema / DTD documents

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WSDL Hello World
Consider the following RMI interface
public interface Hello extends Remote String
sayHello() throws RemoteException

• A common model for java developers
• Describe web service via a simple java interface
• Use tools provided to generate WSDL, stubs,
  ties
• Server-side often implemented as a servlet in J2EE

Source http//www.novell.com/documentation/lg/wor
kbench4/docs/jbroker-web/docs/tutorial
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Hello World WSDL Version
lt?xml version"1.0" encoding"UTF-8"?gt ltdefinition
s name"HelloService" targetNamespace"http//www.
helloWSDL" xmlns"http//schemas.xmlsoap.org/wsdl/
" xmlnssoap"http//schemas.xmlsoap.org/wsdl/soap
/" xmlnssoapenc"http//schemas.xmlsoap.org/soap/
encoding/" xmlnstns"http//www.helloWSDL"
xmlnsxsd"http//www.w3.org/2001/XMLSchema"gt lttyp
es/gt ltmessage name"sayHelloRequest"/gt ltmessage
name"sayHelloResponse"gt ltpart name"arg0"
type"xsdstring"/gt lt/messagegt ltportType
name"Hello"gt ltoperation name"sayHello"gt ltinput
message"tnssayHelloRequest"/gt ltoutput
message"tnssayHelloResponse"/gt lt/operationgt lt/po
rtTypegt ltbinding name"HelloBinding"
type"tnsHello"gt ltsoapbinding style"rpc"
transport"http//schemas.xmlsoap.org/soap/http"/gt
ltoperation name"sayHello"gt ltsoapoperation
soapAction"http//www.helloWSDL/sayHello"/gt ltinp
utgt ltsoapbody encodingStylehttp//schemas.xmlsoa
p.org/soap/encoding/ namespace"http//www.hello
WSDL" use"encoded"/gt lt/inputgt ltoutputgt
ltsoapbody encodingStylehttp//schemas.xmlsoap.or
g/soap/encoding/ namespace"http//www.helloWSDL
" use"encoded"/gt lt/outputgt lt/operationgt lt/bindi
nggt ltservice name"HelloService"gt ltport
binding"tnsHelloBinding" name"HelloPort"gt ltso
apaddress location"http//localhost9090/helloWS
DL"/gt lt/portgt lt/servicegt lt/definitionsgt
Not something you'd normally want to write by
hand
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XML Encryption
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XML Encryption

• Quick History
• Jan 2001 W3C formed XML Encryption WG
• Oct 2002 Spec published
• Dec 2002 Spec approved as a Recommendation
• What service does it provide?
• Confidentiality
• Why not just use SSL?
• SSL privacy of data "in transit" over network
  links
• SSL doesnt help with "data-at-rest" (DAR)
• XML Encryption is one answer
• FileSec is another ?

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Authors, Spec, Namespace

• The Spec
• Primary Authors IBM, Microsoft, XMLSec
• See http//www.w3.org/TR/xmlenc-core
• Version identified by namespace
• xmlnsxenc'http//www.w3.org/2001/04/xmlenc'
• NOTE for brevity in examples in this section,
  I'll often make the following shorthand
  substitution

c xmlnsxenc'http//www.w3.org/2001/04/xmlenc'
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XML Encryption

• Why is it needed?
• Could encrypt using existing approaches
• Rationale similar to XML Signature

ltMyDocumentgt lt/MyDocumentgt
Portion Encrypted by Ann
Portion Encrypted by Fred
Provides a standard XML-based approach
ltSomePlaintextgt lt/SomePlaintextgt
Portion Encrypted by Ann
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What can be encrypted?
Encrypt entirely
Original Document
ltMyDocgt ltE1gtval1lt/E1gt ltE2gtval2lt/E2gt lt/MyDocgt
ltMyDocgt ltE1gtval1lt/E1gt ltE2gtval2lt/E2gt lt/MyDocgt
Encrypt element
Encrypt element content
ltMyDocgt ltE1gtval1lt/E1gt ltE2gtval2lt/E2gt lt/MyDocgt
ltMyDocgt ltE1gtval1lt/E1gt ltE2gtval2lt/E2gt lt/MyDocgt

• Also, can encrypt non-XML data (e.g., external
  files)

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ltEncryptedDatagt
? zero or one occurences

• ltEncryptedDatagt
• Replaces element or element value that it
  encrypts
• Can be either the root of document or a child of
  another document

ltEncryptedData Id? Type? MimeType? Encoding?gt
ltEncryptionMethod/gt? ltdsKeyInfogt ltEncryptedKe
ygt? ltAgreementMethodgt? ltdsKeyNamegt? ltdsRet
rievalMethodgt? lt/dsKeyInfogt? ltCipherDatagt ltCi
pherValuegt? ltCipherReference URI?gt? lt/CipherDat
agt ltEncryptionPropertiesgt? lt/EncryptedDatagt
ltCipherDatagt is the only required element
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Example Encrypt an Element
ltExample1gt ltElementgt data lt/Elementgt lt/Example
1gt
Serialize to UTF-8
Encryption Algorithm
Base64 encode
ciphertext
Key
Package in XML
Compare to original
ltExample1gt ltEncryptedDatagt ltCipherDatagt ltCi
pherValuegt a6b28c4 lt/CipherValuegt lt/Ciph
erDatagt lt/EncryptedDatagt lt/Example1gt
ltEncryptedData gt ltCipherDatagt ltCipherValuegt a6
b28c4 lt/CipherValuegt lt/CipherDatagt lt/EncryptedDa
tagt
Replace Element with cipher text
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Example Encrypt Entire Document
lt?xml version"1.0"gt ltPaymentInfo
xmlns'http//example.org/paymentv2'gt ltNamegtJohn
Smithlt/Namegt ltCreditCard Limit'5,000'
Currency'USD'gt ltNumbergt4019 2445 0277
5567lt/Numbergt ltExpirationgt05/03lt/Expirationgt
lt/CreditCardgt lt/PaymentInfogt
lt?xml version"1.0"gt ltEncryptedData
xmlnsxenc'http//www.w3.org/2001/04/xmlenc'
MimeType"text/xml"gt ltCipherDatagt ltCipherValu
egtA23B45C56lt/CipherValuegt lt/CipherDatagt lt/Encryp
tedDatagt
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Example Encrypt Element Contents
original
element
element contents
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Referenced External Data

• Suppose we have an external file (say cc.jpg)
  that we reference from our XML document
• How to deal with this?
• Option 1 Don't use XML encryption
• Use an ordinary ltImagegt tag to refer to image
• Encrypt cc.jpg separately. Call result
  cc.jpg.enc.
• Rename to cc.jpg.enc in reference above
• Con encryption outside of XML encryption
  standard

ltPaymentInfo xmlns"http//example.org/paymentv2"'
gt ltNamegtJohn Smithlt/Namegt ltCreditCardImage
id"JohnSmithCreditCardImage"gt ltImage
type"front" ref"http//www.xyz.com/cc/images/
JohnSmithCreditCard/cc.jpg"/gt lt/CreditCardgt lt/Pay
mentInfogt
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External Data (cont.)

• Option 2 encrypt the element that references
  the image

ltPaymentInfo xmlns"http//example.org/paymentv2"gt
ltNamegtJohn Smithlt/Namegt ltCreditCardImage
id"JohnSmithCreditCardImage"gt ltEncryptedData
xmlns"c" Type"cElement"gt ltCipherDatagtltCipher
ValuegtA23B45C56lt/CipherValuegtlt/CipherDatagt lt/Enc
ryptedDatagt lt/CreditCardgt lt/PaymentInfogt
This example assumes the image is "safe" already
here we just encrypt the reference to the file.
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External Data (cont.)

• Option 3 use ltCipherReferencegt

ltPaymentInfo xmlns'http//example.org/paymentv2'gt
ltNamegtJohn Smithlt/Namegt ltCreditCardImage
id'JohnSmithCreditCardImage'gt ltEncryptedData
xmlns"c" Type"cElement" MimeType"image/jpeg"
ID"JohnSmithEncryptedCreditCardImagegt ltCiph
erDatagt ltCipherReferencegt URI"http//www.xyz.co
m/cc/images/JohnSmithCreditCard/cc.jpg" lt/Cipher
Referencegt lt/CipherDatagt lt/EncryptedDatagt lt/Cr
editCardgt lt/PaymentInfogt
CipherReference means data is encrypted elsewhere.
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Crypto Details Implicit vs. Explicit

• In examples thus far
• Encryption algorithm key have been implicit
• Sender/Receiver must agree in advance
• Specifying the encryption algorithm
• Use ltEncryptionMethodgt element
• Child of ltEncryptedDatagt
• Example
• What about the key information?
• Next slide

ltEncryptionMethod Algorithm"ctripledes-cbc"/gt
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ltdsKeyInfogt element

• Conveys information about keys used for
  encryption
• An optional child of ltEncryptedDatagt
• If we do public key encryption, could include the
  certificate in ltdsKeyInfogt
• Knowing this, the recipient would know which
  private key to use. Useful for decrypting a
  session key.
• Or, if not using a PKI, can use a shared
  key/password to encrypt the session key. Use
  ltEncryptedKeygt for this(next slide)

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ltEncryptedKeygt
ltEncryptedKey ID'EK' xmlns'c'gt ltEncryptionMeth
od Algorithm"crsa-1_5"/gt ltdsKeyInfo
xmlnsds'c'gt ltdsKeyNamegtPublishKey1lt/dsKeyNa
megt lt/dsKeyInfogt ltCipherDatagt ltCipherValuegtd1
za5clt/CipherValuegt lt/CipherDatagt ltReferenceListgt
ltDataReference URI'ED'/gt lt/ReferenceListgt lt/
EncryptedKeygt
How we refer to the key
The encrypted key
Identifies the data we encrypted with this key
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More on Encryption Algorithms

• XML Encryption does not define any new algorithms
• That would be foolish
• Implementations must support
• Triple DES, AES-128, and AES-256
• But can choose any supported algorithm
• e.g., RC4, IDEA, DES, Skipjack, AES-192

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XML Encryption and Java
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XML Encryption and Java

• JSR 106
• http//www.jcp.org/en/jsr/detail?id106
• Implementations
• VeriSign
• IBM
• Phaos
• IAIK
• Apache

Proprietary APIs
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Example VeriSign

• Trust Services Integration Kit
• http//www.verisign.com/products-services/security
  -services/pki/xml-trust-services/index.html
• I downloaded to C\java\tsik
• Version 1.1
• See http//www.verisign.com/developer/xml

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Let's Encrypt ltCreditCardgt Element
File "Order.xml"
ltOrdergt ltOrderIdgt04212003001lt/OrderIdgt ltCustomer
gtFred Smithlt/Customergt ltProductgt42" Flat Screen
TVlt/Productgt ltCreditCardgt ltNumbergt1234-4321-567
8-9876lt/Numbergt ltExpirationgtMay-2009lt/Expiration
gt lt/CreditCardgt lt/Ordergt
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Example Encryption - VeriSign
import com.verisign.xmlenc. import
com.verisign.xpath.XPath import
javax.xml.parsers. import org.apache.xml.seriali
ze. import org.w3c.dom. import
javax.crypto. import java.io.File class
XMLEncryptionDemo public static void
main(String args)throws Exception new
XMLEncryptionDemo().test() public void
test() throws Exception // Read XML document
from a file into a DOM document DocumentBuilderF
actory dbf DocumentBuilderFactory.newInstance()
dbf.setNamespaceAware(true) DocumentBuilder
db dbf.newDocumentBuilder() File file new
File("Order.xml") Document doc
db.parse(file) // In-memory DOM tree from file
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Example Encryption VeriSign (Cont.)
// Generate a triple DES key to use in
encrypting the XML document KeyGenerator
keyGenerator KeyGenerator.getInstance("DESede")
keyGenerator.init(168) SecretKey secretKey
keyGenerator.generateKey() // Create an
encryptor for this document then encrypt and
output Encryptor e new Encryptor(doc,
secretKey, AlgorithmType.TRIPLEDES) Document
encryptedDoc e.encrypt(new XPath("/Order/CreditC
ard")) output(encryptedDoc, "ENCRYPTED
VERSION") // Decrypt and output the document
using the same key String ns "xenc",
"http//www.w3.org/2001/04/xmlenc" XPath
xpath new XPath(".//xencEncryptedData", ns)
Decryptor d new Decryptor(encryptedDoc,
secretKey, xpath) output(d.decrypt(),
"DECRYPTED VERSION")
Find the ciphertext
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Example Encryption VeriSign (Cont.)
/ Output a document to standard output
/ private void output(Document d, String title)
throws Exception System.out.println("\n---"ti
tle"---") OutputFormat format new
OutputFormat(d) format.setIndent(3)
XMLSerializer output new XMLSerializer(System.
out, format) output.serialize(d)
Note Did not use ltEncryptedKeygt in this example,
so key must already be known to decryptor.
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Output
Decrypt of encryption
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SAML
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SAML

• Security Assertions Markup Language
• An OASIS standard
• http//www.oasis-open.org/committees/tc_home.php?w
  g_abbrevsecurity
• SAML is part of foundation of Liberty Alliance
• Federated network identity on the Internet
• Contrast with Microsoft's Passport

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http//www.projectliberty.org
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Meanwhile in Redmond
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The Problem and Its Implications

• The Problem
• No standard way to share security attributes
  (e.g., authentication authorization data)
  between organizations engaged in distributed
  interactions.
• The Frequent Result?
• Proprietary, tightly-coupled systems
• Multiple logins
• Higher costs
• Many see XML as a basis for a solution
• Thus, SAML

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Use Cases

• Major use cases motivating SAML
• Single Sign on (SSO)
• Backoffice
• Authorization service

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Single Sign On
Ideally, Employee logs in just once in spite of
multiple domains
Security Domain 1
1. Authenticate
Web Site 1
Employer
Employee
Security Domain 2
Web Site 2
2. Order parts
Parts Supplier
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Backoffice Transaction
Parts Supplier
Security Domain 1
Web Site 1
2. Order parts
Employee
Security Domain 2
Web Site 2

• Authenticate, Place order

Employer
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Authorization
Policy Enforcement Point
Access resource
Employee
OK?
Yes (or No)
Policy Decision Point
Security Domain
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Assertions

• The Assertion
• An optionally signed statement / declaration
  concerning some aspect of a subject
• A fundamental abstraction in SAML
• Types of "statements" appearing in assertions
• Authentication
• Attribute
• Authorization
• Can extend to create own assertion types

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Assertion Contents

• Timestamp
• Assertion ID
• Subject name security domain
• Validity conditions
• Validity period
• Audience and target restrictions
• Set of Assertion Statements

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Authentication Statement

• States that a subject was authenticated via a
  given means at a given date/time.
• SAML does not do the authentication
• Instead, one can use SAML to record that it
  happened in a standard way

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Attribute Statement

• An issuing authority asserts that
• subject S
• is associated with attributes X, Y, Z
• with values a, b, c(XML fragments)
• Typical source is LDAP
• john.doe in example.com
• is associated with attribute Department
• with value Human Resources

Source Netegrity
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Example Assertion (has 2 stmts)

• John Doe logged in at 9AM at example.com. He is
  a manager with spending limit of 10K.
• ltsamlassertion Issuerexample.comgt
  ltsamlConditions NotBefore NotAfter/gt
  ltsamlAuthenticationStatement
  AuthenticationMethod
  AuthenticationInstant gt ltsamlsubject
  gtJohn Doelt/samlsubjectgt lt/samlAuthenticatio
  nStatementgt
• ltsamlAttributeStatementgt ltsamlsubject
  gtJohn Doelt/samlsubjectgt ltsamlAttribute
  AttributeNameTitle gt
  ltsamlAttributeValuegtManagerlt/AttributeValuegt
  lt/samlAttributegt ltsamlAttribute
  AttributeNameSpendLimit gt
  ltsamlAttributeValuegt10,000lt/AttributeValuegt
  lt/samlAttributegt lt/samlAttributeStatementgt
  lt/samlAssertiongt

Source Netegrity
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Authorization Statement

• An issuing authority decides whether to grant the
  request
• by subject S
• to perform action A
• on resource R
• given evidence E (other assertions)
• The subject could be a human or a program
• The resource could be a web page or a web
  service, for example

Source Netegrity
50
Example Authorization Decision Assertion

• ltsamlAssertion gt ltsamlConditions
  /gt ltsamlAuthorizationDecisionStatement Decis
  ionPermit
• Resourcehttp//jonesco.com/rpt_12345.htmgt
• ltsamlActiongtREADlt/samlActiongt ltsamlEvidence
  gtlt/samlEvidencegt ltsamlSubjectgt ltsamlNameI
  dentifier SecurityDomainsmithco.com Nam
  ejoeuser /gt lt/samlSubjectgt lt/samlAuthoriza
  tionDecisionStatementgtlt/samlAssertiongt

Source Netegrity
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SAML and Java

• JSR-155 Java API standard and Reference
  Implementation
• http//www.jcp.org/en/jsr/detail?id155
• Mission
• To provide a set of APIs, exchange patterns
  implementation to securely (integrity and
  confidentiality) exchange assertions between web
  services based on OASIS SAML
• Originally submitted by CISCO
• Seems dead (10/2001 last activity)

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Other Sources of SAML java toolkits

• Open SAML
• http//www.opensaml.org
• java and C versions of SAML
• SourceId SAML 1.1 Java Toolkit
• 11-14-2005
• http//www.sourceid.org/projects/saml_1.1_toolkit

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Vendors Who are "SAML-Enabled"

• IBM ? Tivoli Access Manager
• Oblix ? NetPoint
• SunONE ? Identity Server
• Baltimore ? SelectAccess
• Entegrity ? Solutions AssureAccess
• Netegrity ? SiteMinder
• Sigaba ? Secure Messaging Solutions
• RSA Security ? ClearTrust
• VeriSign ? Trust Integration Toolkit
• Entrust ? GetAccess

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XACML
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XACML

• eXtensible Access Control Markup Language
• An XML-based language designed for creating
  policies and automating their use to control
  access.
• Started Summer 2001 to consolidate efforts from
  IBM, University of Milan, and others
• From OASIS
• Organization for the Advancement of Structured
  Information Standards
• www.oasis-open.org
• Compatible with OASIS' SAML
• Security Assertions Markup Language
• XACML can provide SAML Authorization Assertion

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XACML

• Both a policy language and access conrol Request
  / Response language in one
• The requester for a resource contacts a PEP to
  attempt access to some resource. PEP obtains
  decision from a PDP.

Policy Enforcement Point (PEP) Where policy is
actually enforced
request
response
Policy Decision Point (PDP) Where policy is
evaluated and a decision rendered
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(No Transcript)
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Simplified Overview
Decision Request (XML)
Policy Decision Point (PDP)
Policy Enforcement Point (PEP)
Subject
Response (XML)
Policy Info. Point (PIP)

• Response returns one of
• Permit
• Deny
• Indeterminate
• Not Applicable

Policy Admin. Point (PAP)
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Lots of "Points"

• Policy Decision Point (PDP)
• Where a decision is made
• Policy Enforcement Point( PEP)
• Where a decision is enforced
• Policy Information Point (PIP)
• Source of attribute values
• Policy Administration Point (PAP)
• Maintainer of policies, policy sets, rules

• Can co-locate points or distribute them
• Can have multipe of each

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XACML Some Details

• PolicySet Policies, PolicySets
• Policy Rules
• Rule Target Condition Effect
• Target where this rule applies
• Condition predicate to evaluate
• Effect effect to enforce if condition is true
  (permit/deny)
• Each rule results in a decision
• Use combining algorithms to combine decisions

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Available Combining Algorithms

• Policies, Policy Sets, or Rules
• Deny-Overrides
• Permit-Overrides
• First Applicable
• Policies Only
• Only-One-Applicable
• Only one policy should be applicable if gt1, then
  error.

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Basic Structure of a Request

• ltRequestgt
• ltSubjectgt
• ltAttribute AttributeID"" Datatype""gt
• ltAttributeValuegtlt/AttributeValuegt
• lt/Attributegt
• lt/Subjectgt
• ltResourcegt
• ltAttributegtlt/Attributegt
• lt/Resourcegt
• ltActiongt
• ltAttributegtlt/Attributegt
• lt/Actiongt
• lt/Requestgt

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Simplified UML
0..
PolicySet "standard means for combining
separate policies into a single combined policy."
PolicySet -policyCombiningAlgorithm -obligations
(optional)
1
0..
1
0..
Target -subject -resource -action -environment
Policy -ruleCombiningAlgorithm -obligations
(optional)
Basis of an authorization decision
0..1
0..
0..1
0..
Rule -condition (condition) -effect (permit/deny)
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Rule Target

• Defines set of resources, subjects, actions,
  environment to which rule is intended to apply
• Leave any of these blank, and rule applies to all
  entities in that category
• Blank rule target implies that XACML should use
  target of parent policy

65
Relationship to SAML

• SAML Security Associations Markup Language
• Also an OASIS XML-based standard
• Represents assertions
• An optionally signed statement / declaration
  concerning some aspect of a subject
• A fundamental abstraction in SAML
• Types of "statements" appearing in assertions
• Authentication
• Attribute
• Authorization

Could create and pass around the network a SAML
assertion based on an XACML decision
66
Preliminary XACML Impressions

• A maturing specification
• Version 2.0 approved Feb. 2005
• Some formal eval work recently done
• Polar Humenn's paper, 30 Oct. 2003
• The Formal Semantics of XACML
• http//lists.oasis-open.org/archives/xacml/200310/
  msg00094.html

67
Known Implementations

• Sun
• Implements XACML 1.x
• Up to version 1.2
• http//sunxacml.sourceforge.net
• Not a lot of activity (last update June 2006)
• Parthenon Computing
• Implements XACML 1.1 written in C
• http//www.parthenoncomputing.com
• Lagash Systems
• Implements XACML 1.0 written in C (.NET)
• http//mvpos.sourceforge.net
• Jericho Systems
• http//www.jerichosystems.com
• EnterSpace Security Suite XACML-like

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WS-Security
69
WS-Security

• What is it?
• Extensions to SOAP to add security
• Main Goal secure SOAP message exchanges
• Describes how to attach signature and encryption
  headers to SOAP messages. In addition, describes
  how to attach security tokens, including binary
  security tokens such as X.509 certificates and
  Kerberos tickets, to messages.
• Why is it needed?
• Major web services protocols have lacked security
• Use of transport level security (e.g., SSL)
  insufficient
• Want security services closer to the application
  layer
• Want to be transport-independent

70
Players and Standards

• Authors Microsoft, IBM, VeriSign
• Also key authors of
• SOAP request/response protocol for XML messages
• UDDI directory for web services
• WSDL describes web service programmatic
  interface
• OASIS is finally involved
• http//www.oasis-open.org/committees/tc_home.php?w
  g_abbrevwss

71
Bigger Picture Web Services Specs

• WS-Security the first of several security
  specifications
• Examples of future specs
• WS-Policy capabilities and constraints of the
  security policies on intermediaries and endpoints
  (e.g. required security tokens, supported crypto
  algorithms, privacy rules).
• WS-Trust framework for trust models that
  enables Web services to securely interoperate.
• WS-Privacy model for how Web services and
  requesters state privacy preferences and
  organizational privacy practice statements
• Web services security white paper
  http//msdn.microsoft.com/library/default.asp?url
  /library/en-us/dnwssecur/html/securitywhitepaper.a
  sp

?
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Web Services Security Specs
WS-Secure Conversation
WS-Authorization
WS-Federation
Future?
WS-Policy
WS-Trust
WS-Privacy
WS-Security
XML Signature
XML Encryption
WS-SOAP (3/2004 Soap Message Security 1.0)
73
WS-Security Overview

• Goal is to support a variety of security models
• PKI, Kerberos, SSL
• And to support multiple
• Security tokens, encryption technologies
• Trust domains, signature formats
• Non Goals
• Establish security or authentication mechanisms
  requiring multiple exchanges
• Key exchange and derived keys
• Manner is which trust is arrived at

74
WS-Security Details (Cont.)

• Spec depends on
• XML Signature
• XML Encryption
• A soap message consists of an envelope, which
  contains a
• Header (WS-Security elements go here)
• Body
• WS-Security has own namespace
• http//schemas.xmlsoap.org/ws/2002/04/secext

ltSEnvelopegt ltSHeadergtlt/SHeadergt ltSBodygtlt/SB
odygt lt/SEnvelopegt
75
Basic WS-Security Mechanisms

• Security Token Propagation
• Message integrity
• Confidentiality

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Security Token Propagation

• Can add any of 3 new elements to a SOAP header
• Username / password (see below)
• Binary security token, tag ltBinarySecurityTokengt.
  
• Useful for
• X.509 cert (ValueTypewssex509v3)
• Kerberos (ValueTypewsseKerberosv5TGT)
• EncodingType Base64Binary or HexBinary
• External token via a URI, tag ltSecurityTokenRefer
  encegt
• Username / password - XML

• Password types defined
• PasswordText (default)
• PasswordDigest
• Password tag is optional.

ltUsernameToken Idgt ltUsernamegtlt/usernamegt ltP
assword typegtlt/Passwordgt lt/UsernameTokengt
77
Message Integrity

• Accomplished by signing SOAP message
• e.g., add two tags to the envelope header
• ltBinarySecurityTokengt - just discussed
• ltdsSignaturegt - see XML Signature spec
• Signature refers back to the token
• Signature is over message envelope

78
Confidentiality

• Could just rely on SSL
• But that would not be end-to-end
• Plus might not be necessary to encrypt the entire
  envelope, just part of it
• New header added inside of ltwsseSecuritygtlt/wsseS
  ecuritygt
• ltxencReferenceListgt
• ltencDataReference URImyID1/gt
• lt/xencReferenceListgt
• Refers to the encrypted parts of the message
• Uses XML Encryption to create encrypted tags
• Can encrypt session key with public key of
  recipient do this with ltxencEncryptedKeygt tag
  in the header

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XML Key Management System(XKMS)
80
Background

• XML Encryption and XML Signature assume PKI
• We've side-stepped question of how key PKI was
  setup
• PKI setup is hard Why?
• PKI Complexity
• Enrollment multiple approaches
• No standard discovery approach CAs, Certs, Keys
• Cert standardization interpretation
• Trust management
• Chain-building logic
• Cross certification cert hierarchies
• Client handling of complex ASN.1 and PKCS data
  structures
• Revocation/Validation

Adapted from Microsoft
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Objectives of XKMS

• Make PKI-based security easier to use
• Address multi-vendor, cross-platform issues
• Support multiple Trust/PKI infrastructures
• Allow clients to offload complex, and difficult,
  trust assessment
• Integrate key validity checks
• Keep the interfaces simple
• Keep interactions simple

Adapted from Microsoft
82
XKMS

• http//www.w3.org/TR/xkms
• Specifies protocols for distributing and
  registering public keys, suitable for use in
  conjunction with for XML Signature and XML
  encryption.
• Two parts
• XML Key Information Service Spec. (X-KISS)
• XML Key Registration Service Spec. (X-KRSS)

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XKMS Operations

• Register your public key
• Locate other public keys (optional)
• Example find key so you can send encrypted data
  to others
• Check validity/trustworthiness of public keys
• Authentication, Signed documents,
• Possibly before sending encrypted data
• Manage your keys
• Revoke
• Update associated attributes
• Recover/roam your private key

Adapted from Microsoft
84
Overview
http//www.nwfusion.com/news/tech/2003/0908techupd
ate.html
85
Who has XKMS?

• VeriSign part of TrustCenter
• http//www.xmltrustcenter.org/xkms/index.htm
• Entrust has an old reference implementation
  may be defunct now.

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Java Web Services Developer Pack
87
Main Contents of JWSDP

• WSDL
• SOAP
• UDDI
• JAX-RPC
• Web Services Security (XWS-Security)
• SOAP Message Security (WS-Security)
• Apache XML-DSig
• Apache XML-Enc
• Not JSR 105/106 compliant