Java Security

Secret Key Engines

In the JCE, there are new ways to generate keys. Since the existing key engines only operate on public and private keys, the JCE introduces two new engines that can operate on secret keys. Note also in Table 13.1 that the SunJCE security provider implements a new algorithm to generate key pairs for Diffie-Hellman key agreement; that algorithm uses the standard KeyPairGenerator class we explored in Chapter 10.

The KeyGenerator Class

The first engine we’ll look at is the KeyGenerator class (javax.crypto.Key-Generator); this class is used to generate secret keys. This class is very similar to the KeyPairGenerator class except that it generates instances of secret keys instead of pairs of public and private keys:

public class KeyGenerator

Generate instances of secret keys for use by a symmetric encryption algorithm.

The KeyGenerator class is an engine within the JCE. As such, it has all the hallmarks of a cryptographic engine. It has a complementary SPI and a set of public methods that are used to operate upon it, and its implementation must be registered with the security provider.

Using the KeyGenerator class

Like other engine classes, the KeyGenerator class does not have any public constructors. An instance of a KeyGenerator is obtained by calling one of these methods:

public static final KeyGenerator getInstance(String algorithm) , public static final KeyGenerator getInstance(String algorithm, String provider)

Return an object capable of generating secret keys that ...