communication

[Dave]

Gang,

I am writing a web service and need to be able to authenticate
and pass an xml document to each client that uses the service. So far
I have the following steps that need to take place:

- we contact the client
- the client sends us their authentication information
- if valid, we send them an xml document containing data
- they create an MD5 hash based on the data they receive and send that
hash back
- we compare that hash against one we've created to make sure the data
is authentic

I have looked into using curl to do the communication back and forth,
but we needed a solution that will allow any clients the ability to
use whatever language (perl, php, asp, c, c++, java, etc) on whatever
platform (Linux,Mac,Windows). As a result, I started looking into
SOAP. Does anyone know if this is a valid option that can accomplish
the goals set forth above? Is there a better option that I've
overlooked?

Thanks,
Dave

[Dave]

bump for help