If after deploying a webapplication on a Weblogic server that takes advantage of the Java authentication API you're experiencing authentication failures and in the API trace log the following message appears:

AUTHp.c([BII)[B():? - decrypt error: IV missing.

Please verify that your WebLogic management server is using the same JRE version as the the managed node. This has been seen to produce the above debug log message and cause authentication failures.