Every time a Reference is succesfully validated on signature verification, a message is logged at level "info". IMO this should be logged at debug, as the default logging level is often "info" in deployments and this is leading to unnecessary output. For example, this is the output for one signature verification in CXF on a WCF interop test (all one signature verification):

17-Apr-2009 18:15:00 org.apache.xml.security.signature.Reference verify
INFO: Verification successful for URI "#Id-4236415"
17-Apr-2009 18:15:00 org.apache.xml.security.signature.Reference verify
INFO: Verification successful for URI "#id-6"
17-Apr-2009 18:15:00 org.apache.xml.security.signature.Reference verify
INFO: Verification successful for URI "#id-7"
17-Apr-2009 18:15:00 org.apache.xml.security.signature.Reference verify
INFO: Verification successful for URI "#id-8"
17-Apr-2009 18:15:00 org.apache.xml.security.signature.Reference verify
INFO: Verification successful for URI "#id-9"
17-Apr-2009 18:15:00 org.apache.xml.security.signature.Reference verify
INFO: Verification successful for URI "#Timestamp-3"
17-Apr-2009 18:15:00 org.apache.xml.security.signature.Reference verify
INFO: Verification successful for URI "#SigConf-4"

XML-Security has very few logs at "info", and lots at "debug" so I think it's correct to change this. The change is:

org.apache.xml.security.signature.Reference

Replace 

764: log.info("Verification successful for URI \"" + this.getURI() + "\"");

with

764: log.debug("Verification successful for URI \"" + this.getURI() + "\"");