1) Securing an MTOM-enabled message with WS-Security
Let's look at the outbound case first. There is a new configuration option in WSS4J 2.2.0:
- expandXOPInclude: Whether to search for and expand xop:Include Elements for encryption and signature (on the outbound side). This means that the referenced bytes are encrypted/signed, and not just the references. The default is false on the outbound side in WSS4J.
The way this configuration option works is that it scans all children of all message elements to be signed/encrypted, and inlines any xop:Include bytes that it finds before signature/encryption. For the encryption case, if the "storeBytesInAttachment" configuration option is set to true (false in WSS4J, true by default in CXF if MTOM is enabled), the encrypted bytes are then stored in a message attachment. For signature, the original Element is retained and the inlined version is discarded and not included in the request, meaning that the signed bytes are not modified as a message attachment.
2) Validating an MTOM-enabled message with WS-Security
On the inbound side, the "expandXOPInclude" configuration option also applies:
- expandXOPInclude: Whether to search for and expand xop:Include Elements prior in signed elements to signature verification. The default is "true". Note that this replaces the previous "expandXOPIncludeForSignature" configuration option prior to WSS4J 2.2.0.