Security identifier can can take the following values:
1 - SignedSMIME
2 - EnvelopedSMIME
3 - SignedAndEnvelopedSMIME
4 - EnvelopedAndSignedSMIME
Anything else means that there is no security issues and pure email will be sent.
Use the static load method to load classes that implement tool
agents from jars encountered in CLASSPATH like properties or located in a
plugin directory.