1. Secure Systems

2. Distribution Lists
Remote exploder: Send to a distribution list maintainer; it sends to all
Local exploder: Get the list from the distribution list manager; send it to all yourself
Possibility of infinite loop
Comparison (page 503)

3. Security Services for E-Mail
Privacy
Authentication
Integrity
Non-repudiation
Proof of submission
Proof of delivery
Message flow confidentiality
Anonymity
Containment
Audit
Accounting
Self destruct (
Message sequence integrity

4. Establishing Keys Get other party’s Public keys
Establish secret keys through KDC like server

5. Privacy Forwarders (http://support.globat.com/sc/index.php/Forwarders)
End-to-end privacy: If there is only recipient, sender would encrypt using the recipient's public key.
If there are more than one recipients, the message needs to be encrypted using multiple public keys.
If there is a distribution exploder, the sender can encrypt the message using a one-time key, and send the encrypted message and key to the distributor. Exploder will re-encrypt S with its public key and send it along with the encrypted message.

6. Authentication of the Source and Message Integrity
Source authentication
Based on public key---digital signature
Based on secret keys---MAC and MIC
Message integrity---digest
Non-repudiation:
With Public key---digest
With secret keys---Using a trusted third party/notary

7. S/MIME

8. What is MIME? Multipurpose Internet Mail Extensions
It is the official proposed standard format for extended Internet electronic mail.
Internet messages consist of two parts, the header and the body.
The header forms a collection of field/value pairs structured to provide information essential for the transmission of the message. The body is normally unstructured unless the is in MIME format.
MIME defines how the body of an message is structured. The MIME format permits to include enhanced text, graphics, audio, and more in a standardized manner via MIME-compliant mail systems.
However, MIME itself does not provide any security services. The purpose of S/MIME is to define such services, following the syntax given in PKCS #7 for digital signatures and encryption. The MIME body section carries a PKCS #7 message, which itself is the result of cryptographic processing on other MIME body sections.

9. S/MIME (Secure / Multipurpose Internet Mail Extensions) is a protocol that adds digital signatures and encryption to Internet MIME.
S/MIME has been endorsed by a number of leading networking and messaging vendors, including ConnectSoft, Frontier, FTP Software, Qualcomm, Microsoft, Lotus, Wollongong, Banyan, NCD, SecureWare, VeriSign, Netscape, and Novell.