Notes for March 2, 1998
- Greetings and felicitations!
- Reading: Pfleeger, pp. 377-426;
Garfinkel & Spafford, pp. 449-478, 669-700
- Chinese Wall
- Theme: market analyst must uphold confidentiality requirements
(no use of insider knowledge) but can advise different
- Data items: "objects" (axiomatic), "company
datasets" (CD; sets of objects belonging to a company),
"conflict of interest classes" (COI; sets of company
datasets for companies in competition)
- Simple Security Property: Access is only granted if the object
requested (a) is in the same CD as an object already accessed by
the subject, or (b) belongs to an entirely different COI.
- Can derive: if subject accesses object, only other objects in that
same CD can be accessed within the same COI. Also, subject has
access to at most one CD in each COI.
- Sanitization: if it's sanitized then the model does not impose
- *-Property: Write access is only granted if (a) access is
permitted by the simple security rule, and (b) no object can be
read which is in a different CD to the one for which write access
is requested and contains unsanitized information.
- Can derive: the flow of unsanitized information is confined to
its own CD, but sanitized information may flow freely throughout
- BLP: not satisfactory. Say user A accesses company dataset B.
But then A is sick, so management has user C do the access.
Not possible unless we know for certain C has not accessed
anything else in B's COI; BLP doesn't save this info. Also,
BLP fixes what datasets a subject can access; the Wall allows
- Clark-Wilson: can model it exactly.
- Network security
- Main point: just like a system
- Review of ISO model
- data link
- PEM, PGP
- Goals: confidentiality, authentication, integrity,
- Design goals: drop in (not change), works with any RFC 821-
conformant MTA and any UA, and exchange messages without prior
- Use of Data Exchange Key, Interchange Key
- Review of how to do confidentiality, authentication, integrity
with public key IKs
- Details: canonicalization, security services, printable
- Certificate-based key management
- PGP v. PEM
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