S/MIME Packages 
Package Description
org.bouncycastle.mail.smime
High level classes for dealing with S/MIME objects (RFC 3851).
org.bouncycastle.mail.smime.handlers
S/MIME handlers for the JavaMail API.
org.bouncycastle.mail.smime.util
MIME-side helpers used by the S/MIME generators and parsers in org.bouncycastle.mail.smime: body-part output canonicalisation, file-backed data sources for large attachments, and CRLF normalisation.
org.bouncycastle.mail.smime.validator
Higher-level S/MIME signed-message validator that runs structural, signer, and certificate-path checks against a SignedMailValidator.ValidationResult and reports failures as localised messages through ErrorBundle.