Chapter 7 Security

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Message level security can be useful in XML document centric applications,

since different sections of the XML document may have different security require 

ments or be intended for different users.

7.1.2 Security Implications of the Operational Environment

The operational environment within which Web services interactions occur is an

important factor in your security design. Service interactions occurring entirely

within an enterprise have very different security requirements than service interac 

tions open to everyone on the Internet. Thus, the relationship among Web service

participants such as Internet, intranet, and extranet is an important consideration.

When participants are closely aligned, you have a greater ability to negotiate secu 

rity requirements. 

In essence, the more control you have over the environment in which the Web

service participants run, the easier it is to solve your security design. For example,

if the Web services limit communication to applications inside your enterprise,

then the network's physical security might shield the Web service. The operational

environment security might be sufficient to satisfy your security needs. Similarly,

Web services in environments that require communication via a Virtual Private

Network (VPN) might not need to worry about issues such as confidentiality,

since the communication channel is already secure.

When all participants are trusted, such as within one enterprise, it is an easier

matter to set up and exchange security keys. However, this is a difficult challenge

for untrusted participants with an open Internet Web service.

7.2

J2EE Platform Security Model

The J2EE platform container provides a set of security related system services to its

applications and clients. These built in container services simplify application

development because they remove the need for the application developer to write

the security portion of the application logic. 

Security on the J2EE platform is primarily declarative and is specified exter 

nally from the application code. 

Declarative security

 mechanisms used in an

application are expressed via a declarative syntax in a configuration document

called a deployment descriptor. The declarative security model has the advantage

of enabling you to easily change these declarative settings to match security

policy.