In message-layer security, security information is contained within the SOAP message and/or SOAP message attachment, which allows security information to travel along with the message or attachment. For example, a portion of the message may be signed by a sender and encrypted for a particular receiver. When the message is sent from the initial sender, it may pass through intermediate nodes before reaching its intended receiver. In this scenario, the encrypted portions continue to be opaque to any intermediate nodes and can only be decrypted by the intended receiver. For this reason, message-layer security is also sometimes referred to as end-to-end security.
The advantages of message-layer security include the following:
Security stays with the message over all hops and after the message arrives at its destination.
Security can be selectively applied to different portions of a message (and to attachments if using XWSS).
Message security can be used with intermediaries over multiple hops.
Message security is independent of the application environment or transport protocol.
The disadvantage of using message-layer security is that it is relatively complex and adds some overhead to processing.
The Application Server supports message security. It uses Web Services Security (WSS) to secure messages. Because this message security is specific to the Application Server and not a part of the Java EE platform, this tutorial does not discuss using WSS to secure messages. See the Sun Java System Application Server 9.1 Administration Guide and Sun Java System Application Server 9.1 Developer’s Guide for more information.