Java in a Nutshell, 5th Edition

Name

Package java.security

Synopsis

The java.security package contains the classes and interfaces that implement the Java security architecture. These classes can be divided into two broad categories. First, there are classes that implement access control and prevent untrusted code from performing sensitive operations. Second, there are authentication classes that implement message digests and digital signatures and can authenticate Java classes and other objects.

The central access control class is AccessController; it uses the currently installed Policy object to decide whether a given class has Permission to access a given system resource. The Permissions and ProtectionDomain classes are also important pieces of the Java access control architecture.

The key classes for authentication are MessageDigest and Signature; they compute and verify cryptographic message digests and digital signatures. These classes use public-key cryptography techniques and rely on the PublicKey and PrivateKey interfaces. They also rely on an infrastructure of related classes, such as SecureRandom for producing cryptographic-strength pseudorandom numbers, KeyPairGenerator for generating pairs of public and private keys, and KeyStore for managing a collection of keys and certificates. (This package defines a Certificate interface, but it is deprecated; see the java.security.cert package for the preferred Certificate class.)

The CodeSource class unites the authentication classes with the access ...