...
<field type="..." variable="...">
<spec>
...
<processor class="fully.qualified.ProcessorClassName" [backupVariable="..."]>
<configuration>
<whatever <whatever-param-name>MySecretKey...</whatever-param-name>
<another-param2-name>AES...</another-param2-name>name>
... </configuration>
</processor>
</spec>
<validator class="fully.qualified.ValidatorClassName" txt="..." id="..."/>
</field>
or in an alternative notation:
<field type="..." variable="...">
<spec>
...
<processor class="fully.qualified.ProcessorClassName" [backupVariable="..."]>
<configuration>
<param name="whatever-param-name" value="..."/>
<param name="another-param2-name" value="..."/>
... </configuration>
</processor>
</spec>
<validator class="fully.qualified.ValidatorClassName" txt="..." id="..."/>
</field>
...