Front cover - IBM Redbooks

6.3 Summary
280 Lotus Security Handbook
Receiving signed S/MIME messages
Upon receipt of signed e-mail, Notes will try to verify the validity of the signature.
If the user trusts the signing certificate, that is, if the user has a certificate of the
signer or an Internet cross-certificate to the sender, a message will be displayed
in the Notes client’s status bar indicating the validity of the signature, an example
of which is the following:
"Signed By: Bob, at 10:52 AM, According To: TestCertAuthority".
If the user doesn’t trust the signing certificate, the user will receive a prompt to
create an Internet cross-certificate on demand. The user can select the subject
name of the certificate in the message that the user wishes to trust.
Note: Signed S/MIME messages contain the certificate chain of sender and
signers. The resulting Internet cross-certificate is stored in the receiver's
Personal Address Book. By creating the cross-certificate, the user is asserting
that he or she trusts a certificate contained in the S/MIME signed message.
Signature verification can then proceed.
Finally, it is also possible for the user to manually store the sender's address and
X.509 certificates to his or her Personal Address Book. When viewing S/MIME
signed mail, the user should select the Actions → Tools → Add Sender to
Address Book menu options. It’s important to note here that this certificate is
not an Internet cross-certificate, meaning it is not used when sending or receiving
signed S/MIME e-mails, it is used to encrypt messages from the user to the
sender.
While the Internet permits individuals and organizations to communicate like
never before, at the same time, the single greatest problem with the Internet has
been, and still is, the problem of “who can be trusted?”
This chapter showed the role that public key infrastructures can play in
establishing this trust and ensuring its integrity. This is done through the use of
X.509 certificates in conjunction with established protocols (for example, SSL)
and in conjunction with established messaging standards (for example, S/MIME).
As well, this chapter showed how support for X.509 certificates is implemented in
Notes and Domino and how certificates are requested, approved, generated, and
installed in a Notes and Domino infrastructure.