Grid Services Orchestration with OMII-BPEL - Grid Computing: Infrastructure, Service, and Applications - page 211

8.21
As a center point of communication in service orchestration, a BPEL engine
interacts with services scattered on networks, some of which may even be
beyond organization boundaries. With exceptions, traditional security
requirements of protecting private data and restricting access to logic still
need to be handled by applications in a service-oriented environment. We
will now explain the well-received security standard designed for the Web
service framework, in particular the Web Service Security (WSS).
Conventionally, the protection enforced at the transport layer, like the
secure socket layer (SSL), is no doubt a popular means of securing com-
munication channels along which conversations are maintained. WSS, on
the other hand, which protects the coni dentiality and integrity of SOAP
messages by digitally signing and encrypting XML elements in a message,
is of importance for achieving end-to-end security in the application layer,
which is vital to secure a message-centric interaction model that SOAP
depends on.
Over HTTPS channels, OMII has implemented its WSS framework.
A security header that contains the message signature and sender identity
is inserted in every outbound message. Verii cation is performed at the
intended recipient using the public key embedded in the X.509 certii cate
sent alongside. The certii cates are issued for every instance of OMII server
and client during the installation. WSS standardizes how this security
information should be attached to the SOAP messages. All OMII-hosted
services, which conform to the security policies, can be seamlessly
orchestrated by ActiveBPEL, which in turn has been integrated into the
framework. WSE in BPEL Designer, as the client-side program, can invoke
any of these services safely as we have mentioned earlier.

Security

8.22
The case study we have used is in the area of theoretical chemistry.
Chemists look for different crystal structures, or polymorphs, of given
organic molecules because the resulting characteristics that vary under
different physical conditions are essential to determine solid states of,
for example, pharmaceutical substances, industrial materials, and so on
(shown in Figure 8.6 ) . Among the available approaches, such as labora-
tory experiments, one has to computationally exhaust all theoretic possi-
bilities using established scientii c models, the results of which can then be
cross-checked against those produced by companion approaches for i nal
coni rmation that scientists can reply on for subsequent study.

A Polymorph-Search Case Study