The buzz accompanying Web services today no longer vibrates around system
integration and XML interfaces, but around security — and the frantic, mish-mashed
efforts to create security standards.
Web services are built with standard interfaces based on the Simple Object
Access Protocol (SOAP) from the World Wide Web Consortium (W3C). But because SOAP is not secure
at this point, Web services cannot achieve their mission of enabling business-to-business
commerce and integration of business partners' disparate platforms, network
executives say.
Without security in the Web services framework/architecture, development
of other Web services standards for e-commerce also will suffer, including
those to support reliable and asynchronous messaging, business-process workflow
and transactional integrity.
"Security is a rollout inhibitor today, absolutely," says Mark Jones, vice
president of business development for the National Student Clearinghouse (NSC),
a nonprofit organization in Herndon, Va., that provides university enrollment
and degree verification services to lenders and businesses. NSC knows the
issues firsthand, as it is on the verge of deploying two Web services to streamline
the collection and dispersal of its data to potentially millions of partners.
Jones likens the challenge of establishing Web services for partner-to-partner
trading to using public-key infrastructure and electronic data
interchange. While standards-based partner-to-partner transactions
are great conceptually, they're difficult to implement. "Having
just been through that for 10 or 15 years with EDI, [I know] it
is a very tough problem to solve," he says. "No one has really
perfected a way to do partner-to-partner trading yet. So we question
the evolution of the standards and how well they will work."
Jones isn't alone. Recent surveys by Hurwitz Group and ZapThink
show that security is the No. 1 obstacle to adoption of corporate
Web services.
Of course, security can be added to SOAP via extensions, and
so a flurry of work to do so is in progress — spanning three standards
bodies that have produced complementary but sometimes overlapping
protocols (see graphic).
Extensions will standardize ways for systems to prove their identities, validate
user authorization and access credentials, guarantee confidential transactions,
and ensure integrity and nonrepudiation.
While waiting on standards ratification and vendor implementation of those
extensions, many network executives are limiting Web services to intranet
projects or improvising security when Web services traverse corporate boundaries.
Such improvisation includes homegrown security, fitting established Internet
standards or proprietary products onto projects, or contracting with third
parties to supply security services. NSC sidestepped the standards maze by
using software from Flamenco Networks to wrap authentication, authorization
and management capabilities around its Web services, says Doug Falk,
NSC CIO.
"We probably could have started with weaker encryption and relied on a model
using HTTP-S and authenticating based on a user ID and password. That would
have worked for a period of time until someone raised concerns over that model
being too weak," Falk says.
The rush is on
Meanwhile, XML standards bodies have been busy. The Internet Engineering
Task Force (IETF), the Organization for the Advancement of Structured Information
Standards (OASIS) and the W3C are working on or have completed no fewer than
13 security protocols usable with Web services. These include extensions for
encryption, digital signatures, nonrepudiation and long-accepted standards
such as Kerberos that are being folded into the Web services mold.
With so many cooks in the kitchen, the industry lacks a clear
view of how individual Web services security specifications will
be melded into an interoperable security framework.
To their credit, OASIS and W3C are comparing their efforts with the aim of
clarifying the security work. "If any of these security specifications are
going to work together, we have to work together," says Karl Best, director
of technical operations for OASIS.
The cooperation began with WS-Security, a specification proposed by IBM, Microsoft
and VeriSign in April and turned over to OASIS last month. WS-Security, which
lets Web services pass secure and signed SOAP messages, has at its core the
W3C's XML Encryption and XML Digital Signature and will add six other extensions
for functions such as expressing security policies, trust relationships, federation
and authorization. Then last month, OASIS and W3C sponsored a forum to compare
and contrast work being done by both groups.
In addition to XML Digital Signature and XML Encryption, W3C is developing
the XML Key Management Specification and a Web Service Architecture that includes
a security framework. Meanwhile, OASIS is developing the Security Assertion
Markup Language (SAML) for authentication and authorization,
the Extensible Access Control Markup Language, Service Provisioning Markup
Language and the XML Common Biometric Format.
The IETF's work centers on standards for transport-level security on which
OASIS and W3C are building application-level security protocols.
The groups need to develop a conceptual "security stack" model that illustrates
how various protocols will rely on each other, rather than compete,
says Ann Thomas Manes, a security expert who works with OASIS
and W3C and is CTO for Web service security vendor Systinet. "The
higher-level items take advantage of the lower levels of the stack.
So WS-Security depends on XML Digital Signature, XML Encryption,
SAML and SOAP," she says.
Corporations pushing ahead
Such a model is logical, but generates only passing interest from corporations
on the cutting edge that want to push their Web services over the firewall
now.
"At this point we are using a standard firewall system with Secure Sockets
Layer encryption, and we have built our own Web services gateway for authentication
and authorization," says Gereon Fredrickson, senior director of technology
products for Galileo International, a provider of data to the travel industry.
While Galileo waits for the interoperability that standards promise, a handful
of vendors offer a collection of middleware software and services to boost
Web services security, including BEA Systems, Cape Clear, Flamenco, Grand
Central Networks, IBM, Iona, Kenamea, Microsoft, Oracle, Sonic, Sun, Systinet
and Tibco.
Galileo, which went live with its first external Web service last month,
is waiting for the security standards landscape to flatten. "There is still
some shake-out that has to happen before we see where the actual standards
will settle. Then we'll see where we can use those," Fredrickson says.
Signs of a settling have begun in that the WS-Security specification is generally
regarded as a competent starting point. It specifies how communication among
Web services will be secured and describes how to put security protocols to
use within SOAP. WS-Security adds security information to the headers of SOAP
messages using XML Encryption, XML Digital Signatures and identity protocols
such as SAML or Kerberos, an IETF standard.
"In terms of pure Web services security, we are just starting out,"
says Bob Sutor, director of e-business standards strategy for IBM. "But WS-Security
starts to lay the foundation."
Settlement also is happening around workflow specifications that will aid
in deploying security at execution points when multiple Web services applications
are tied together across a number of organizations.
Last month, IBM and Microsoft combined their respective Web Services Flow
Language and XLANG to create the Business Process Execution Language for Web
Services. The language lets users specify a collection of Web services and
the order in which they need to be executed as part of a business process
such as filling an order. It joins similar efforts from Sun on Web Services
Choreography Interface and protocols included in OASIS's electronic business
XML specification.
With the stages of a business process defined in a workflow, security tenants
such as encryption, authentication and access control can be defined per stage
instead of blanketing the transaction as a whole. The workflow lets certain
forms of security be applied only where they are needed.
"If you manage the workflow of a transaction, you can trace each step and
make sure security is occurring," says Bernhard Borges, managing director
of the advanced technology group at PricewaterhouseCoopers Consulting. He
says workflow builds a foundation that finally lets multiple Web services
be aggregated into a business transaction.
"Once you get the bits and pieces of workflow, you can start to apply security,"
Borges says.
However, experts say it could take two to five years before the standards
are mature enough for corporate customers to make use of them.
"Without a security and trust infrastructure, Web services will be dead on
arrival," says Phillip Hallam-Baker, principal scientist for VeriSign. "But
people shouldn't be concerned that this is a problem that won't get solved,
because there is very large agreement on the basic approach on how to go about
this."
A
standards mishmash
The Organization for the Advancement of
Structured Information Standards (OASIS) and World Wide
Web Consortium (W3C) have pinpointed 13 specifications
likely to form the foundation of a Web services security
framework.
 |
| Standard
(proposed or final) |
Standards
body/Status |
Description
|
SAML
Security Assertion Markup Language |
OASIS/Final
vote |
Exchanges
user and machine authentication and authorization information. |
XACML
Extensible Access Control Markup Language |
OASIS/Committee
review |
Expresses
policies for information access. |
SPML
Service Provisioning Markup Language |
OASIS/In
committee |
Defines
how to exchange user, resource and service provisioning information. |
| WS-Security |
OASIS/Forming
technical committee |
Extends
Simple Object Access Protocol with XML security protocols. |
XrML
Extensible Rights Management Language |
OASIS/Gathering
requirements |
Manages
copyrights of digital content. |
XCBF
XML Common Biometric Format |
OASIS/Defining scope of work |
Defines
XML codings for Common Biometric Exchange File Format. |
| XML
Digital Signature |
W3C/Completed |
Provides
integrity, signature assurance and non-repudiation. |
| XML
Encryption |
W3C/Final
vote in committee |
Encrypts
and decrypts digital content. |
XKMS
XML Key Management Specification |
W3C/Working
draft |
Provides
a method for obtaining cryptographic keys. |
| Transport
Layer Security/ Secure Sockets Layer |
IETF/RFC 2246 |
Secures
Internet traffic between two points. |
SASL
Simple Authentication and Security Layer |
IETF/RFC
2222 |
Adds
authentication to connection-based protocols. |
| Kerberos |
IETF/RFC
1510 |
Provides
tickets for authenticating users. |
BEEP
Blocks Extensible Exchange Protocol |
IETF/RFC
3080 |
Helps
establish quality of service over the Internet. |
|
|