INTERACTIVE WEB SERVICES WITH JAVA

SSL - Secure Sockets Layer

SSL - the Secure Sockets Layer can be inserted between the application layer (HTTP) and the transport layer (TCP).
using cryptography, it provides privacy and reliability of client-server communication and authentication of the server
first, a secure channel is set up using (slow) public-key encryption (e.g. RSA) to generate a shared secret
subsequently, communication is performed using (fast) symmetric encryption (e.g. DES)
for Web services, just use the https protocol in URLs (assuming that a trusted certificate is generated for the server)
J2SE 1.4 contains Java Secure Socket Extension (JSSE) providing full Java support for SSL (javax.net.ssl)