IBM WebSphere V5.0 Security - CGISecurity

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Users are mapped directly to specifc security roles.
Groups are formed, users are defined as members of a group, and the groups
are defined to specific security roles.
A combination of user/group mapping to security roles is used to handle any
exceptions.
2.2.3 Public Key Infrastructure (PKI)
This section provides a brief overview of the Public Key Infrastructure (PKI). PKI
is a part of IT security and today‘s security needs bring it into focus.
PKI is closely related to cryptography. Although it seems complicated, it is not.
We do not need to use low-level mathematical algorithms, but we do need to
understand the background involved.
Secret key cryptography
The secret key algorithms were invented earlier than were the public key
algorithms. They use one key to encrypt and decrypt the data.
Plain text Encryption Cipher text Decryption Plain text
Figure 2-3 Symmetric key encryption
Figure 2-3 illustrates the concept of symmetric key cryptography. The algorithms
used provide a great advantage: they are faster than the public key cryptography
introduced later. They have a considerable disadvantage as well: the same key is
needed for encryption and decryption, and both parties must have the same
keys. In today‘s cryptography, the secret keys do not belong to persons but to
communication sessions. At the beginning of a session, one of the parties
creates a session key and delivers it to the other party; they can then
communicate securely. At the end of the session, both parties delete the key and,
if they want to communicate again, must create another key.
The following section will discuss how to secure the delivery of the session key.
Public key cryptography
The first imperative of public key cryptography is the ability to deliver the session
keys securely. It has many more benefits than secret key cryptography, as we will
see in the following section.
12 IBM WebSphere V5.0 Security Handbook