Cryptographic Security Architecture: Design and Verification phần 2 doc

1.4 The Object Model 15

Keyset

(database)

Keyset

(smart card)

Private key

object

Certificate

object

Pub.key

object

handles

Figure 1.12. Key container objects.

1.4.5 Security Attribute Containers

Security attribute containers (certificate objects), like keyset objects, are built on the

repository architectural model and contain a collection of attributes that are attached to a

public/private key or to other information. For example signed data often comes with

accompanying attributes such as the signing time and information concerning the signer of

the data and the conditions under which the signature was generated. The most common type

of security attribute container is the public-key certificate, which contains attribute

information for a public (and by extension private) key. Other attribute containers are

certificate chains (ordered sequences of certificates), certificate revocation lists (CRLs),

certification requests, and assorted other certificate-related objects.

1.4.6 The Overall Architectural and Object Model

A representation of some of the software architectural models discussed earlier mapped onto

cryptlib’s architecture is shown in Figure 1.13. At the upper levels of the layered model

(Section 1.2.4) are the envelopes, implementing the pipe-and-filter model (Section 1.2.1) and

communicating through the distributed process model (Section 1.2.6). Below the envelopes

16 1 The Software Architecture

are the action objects (one of them implemented through a smart card) that perform the

processing of the data in the envelopes.

Compress Sign Encrypt

Hash

Private key

Block cipher

Public key

Pipe￾and￾filter

Layered

Hardware

level

Object￾oriented

Distributed

process

Figure 1.13. Overall software architectural model.

Not shown in this diagram are some of the other architectural models used, which include

the event-based model (Section 1.2.3) used for general interobject communications, the

repository model (Section 1.2.5) used for the keyset that supplied the public key that is used

in the third envelope, and the forwarder-receiver model (Section 1.2.7) which is used to

manage communications between cryptlib and the outside world.